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Diffstat (limited to 'png/pngrutil.c')
| -rw-r--r-- | png/pngrutil.c | 4469 |
1 files changed, 0 insertions, 4469 deletions
diff --git a/png/pngrutil.c b/png/pngrutil.c deleted file mode 100644 index cc52202..0000000 --- a/png/pngrutil.c +++ /dev/null @@ -1,4469 +0,0 @@ - -/* pngrutil.c - utilities to read a PNG file - * - * Last changed in libpng 1.6.11 [June 12, 2014] - * Copyright (c) 1998-2014 Glenn Randers-Pehrson - * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) - * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) - * - * This code is released under the libpng license. - * For conditions of distribution and use, see the disclaimer - * and license in png.h - * - * This file contains routines that are only called from within - * libpng itself during the course of reading an image. - */ - -#include "pngpriv.h" - -#ifdef PNG_READ_SUPPORTED - -png_uint_32 PNGAPI -png_get_uint_31(png_const_structrp 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_structrp 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_structrp png_ptr, png_inforp 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_structrp 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_structrp png_ptr, png_bytep buf, png_uint_32 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 an 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_structrp png_ptr, png_uint_32 skip) -{ - /* The size of the local buffer for inflate is a good guess as to a - * reasonable size to use for buffering reads from the application. - */ - while (skip > 0) - { - png_uint_32 len; - png_byte tmpbuf[PNG_INFLATE_BUF_SIZE]; - - len = (sizeof tmpbuf); - if (len > skip) - len = skip; - skip -= len; - - png_crc_read(png_ptr, tmpbuf, len); - } - - if (png_crc_error(png_ptr)) - { - if (PNG_CHUNK_ANCILLARY(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_error(png_ptr, "CRC error"); - - 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_structrp png_ptr) -{ - png_byte crc_bytes[4]; - png_uint_32 crc; - int need_crc = 1; - - if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name)) - { - if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) == - (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN)) - need_crc = 0; - } - - else /* critical */ - { - if (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE) - need_crc = 0; - } - -#ifdef PNG_IO_STATE_SUPPORTED - png_ptr->io_state = PNG_IO_READING | PNG_IO_CHUNK_CRC; -#endif - - /* The chunk CRC must be serialized in a single I/O call. */ - png_read_data(png_ptr, crc_bytes, 4); - - if (need_crc != 0) - { - crc = png_get_uint_32(crc_bytes); - return ((int)(crc != png_ptr->crc)); - } - - else - return (0); -} - -#if defined(PNG_READ_iCCP_SUPPORTED) || defined(PNG_READ_iTXt_SUPPORTED) ||\ - defined(PNG_READ_pCAL_SUPPORTED) || defined(PNG_READ_sCAL_SUPPORTED) ||\ - defined(PNG_READ_sPLT_SUPPORTED) || defined(PNG_READ_tEXt_SUPPORTED) ||\ - defined(PNG_READ_zTXt_SUPPORTED) || defined(PNG_SEQUENTIAL_READ_SUPPORTED) -/* Manage the read buffer; this simply reallocates the buffer if it is not small - * enough (or if it is not allocated). The routine returns a pointer to the - * buffer; if an error occurs and 'warn' is set the routine returns NULL, else - * it will call png_error (via png_malloc) on failure. (warn == 2 means - * 'silent'). - */ -static png_bytep -png_read_buffer(png_structrp png_ptr, png_alloc_size_t new_size, int warn) -{ - png_bytep buffer = png_ptr->read_buffer; - - if (buffer != NULL && new_size > png_ptr->read_buffer_size) - { - png_ptr->read_buffer = NULL; - png_ptr->read_buffer = NULL; - png_ptr->read_buffer_size = 0; - png_free(png_ptr, buffer); - buffer = NULL; - } - - if (buffer == NULL) - { - buffer = png_voidcast(png_bytep, png_malloc_base(png_ptr, new_size)); - - if (buffer != NULL) - { - png_ptr->read_buffer = buffer; - png_ptr->read_buffer_size = new_size; - } - - else if (warn < 2) /* else silent */ - { - if (warn != 0) - png_chunk_warning(png_ptr, "insufficient memory to read chunk"); - - else - png_chunk_error(png_ptr, "insufficient memory to read chunk"); - } - } - - return buffer; -} -#endif /* PNG_READ_iCCP|iTXt|pCAL|sCAL|sPLT|tEXt|zTXt|SEQUENTIAL_READ */ - -/* png_inflate_claim: claim the zstream for some nefarious purpose that involves - * decompression. Returns Z_OK on success, else a zlib error code. It checks - * the owner but, in final release builds, just issues a warning if some other - * chunk apparently owns the stream. Prior to release it does a png_error. - */ -static int -png_inflate_claim(png_structrp png_ptr, png_uint_32 owner) -{ - if (png_ptr->zowner != 0) - { - char msg[64]; - - PNG_STRING_FROM_CHUNK(msg, png_ptr->zowner); - /* So the message that results is "<chunk> using zstream"; this is an - * internal error, but is very useful for debugging. i18n requirements - * are minimal. - */ - (void)png_safecat(msg, (sizeof msg), 4, " using zstream"); -# if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC - png_chunk_warning(png_ptr, msg); - png_ptr->zowner = 0; -# else - png_chunk_error(png_ptr, msg); -# endif - } - - /* Implementation note: unlike 'png_deflate_claim' this internal function - * does not take the size of the data as an argument. Some efficiency could - * be gained by using this when it is known *if* the zlib stream itself does - * not record the number; however, this is an illusion: the original writer - * of the PNG may have selected a lower window size, and we really must - * follow that because, for systems with with limited capabilities, we - * would otherwise reject the application's attempts to use a smaller window - * size (zlib doesn't have an interface to say "this or lower"!). - * - * inflateReset2 was added to zlib 1.2.4; before this the window could not be - * reset, therefore it is necessary to always allocate the maximum window - * size with earlier zlibs just in case later compressed chunks need it. - */ - { - int ret; /* zlib return code */ -# if PNG_ZLIB_VERNUM >= 0x1240 - -# if defined(PNG_SET_OPTION_SUPPORTED) && \ - defined(PNG_MAXIMUM_INFLATE_WINDOW) - int window_bits; - - if (((png_ptr->options >> PNG_MAXIMUM_INFLATE_WINDOW) & 3) == - PNG_OPTION_ON) - window_bits = 15; - - else - window_bits = 0; -# else -# define window_bits 0 -# endif -# endif - - /* Set this for safety, just in case the previous owner left pointers to - * memory allocations. - */ - png_ptr->zstream.next_in = NULL; - png_ptr->zstream.avail_in = 0; - png_ptr->zstream.next_out = NULL; - png_ptr->zstream.avail_out = 0; - - if (png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) - { -# if PNG_ZLIB_VERNUM < 0x1240 - ret = inflateReset(&png_ptr->zstream); -# else - ret = inflateReset2(&png_ptr->zstream, window_bits); -# endif - } - - else - { -# if PNG_ZLIB_VERNUM < 0x1240 - ret = inflateInit(&png_ptr->zstream); -# else - ret = inflateInit2(&png_ptr->zstream, window_bits); -# endif - - if (ret == Z_OK) - png_ptr->flags |= PNG_FLAG_ZSTREAM_INITIALIZED; - } - - if (ret == Z_OK) - png_ptr->zowner = owner; - - else - png_zstream_error(png_ptr, ret); - - return ret; - } - -# ifdef window_bits -# undef window_bits -# endif -} - -#ifdef PNG_READ_COMPRESSED_TEXT_SUPPORTED -/* png_inflate now returns zlib error codes including Z_OK and Z_STREAM_END to - * allow the caller to do multiple calls if required. If the 'finish' flag is - * set Z_FINISH will be passed to the final inflate() call and Z_STREAM_END must - * be returned or there has been a problem, otherwise Z_SYNC_FLUSH is used and - * Z_OK or Z_STREAM_END will be returned on success. - * - * The input and output sizes are updated to the actual amounts of data consumed - * or written, not the amount available (as in a z_stream). The data pointers - * are not changed, so the next input is (data+input_size) and the next - * available output is (output+output_size). - */ -static int -png_inflate(png_structrp png_ptr, png_uint_32 owner, int finish, - /* INPUT: */ png_const_bytep input, png_uint_32p input_size_ptr, - /* OUTPUT: */ png_bytep output, png_alloc_size_t *output_size_ptr) -{ - if (png_ptr->zowner == owner) /* Else not claimed */ - { - int ret; - png_alloc_size_t avail_out = *output_size_ptr; - png_uint_32 avail_in = *input_size_ptr; - - /* 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 reduces the amount of data accessed - * at each step and that may give the OS more time to page it in. - */ - png_ptr->zstream.next_in = PNGZ_INPUT_CAST(input); - /* avail_in and avail_out are set below from 'size' */ - png_ptr->zstream.avail_in = 0; - png_ptr->zstream.avail_out = 0; - - /* Read directly into the output if it is available (this is set to - * a local buffer below if output is NULL). - */ - if (output != NULL) - png_ptr->zstream.next_out = output; - - do - { - uInt avail; - Byte local_buffer[PNG_INFLATE_BUF_SIZE]; - - /* zlib INPUT BUFFER */ - /* 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 of 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. - */ - avail_in += png_ptr->zstream.avail_in; /* not consumed last time */ - - avail = ZLIB_IO_MAX; - - if (avail_in < avail) - avail = (uInt)avail_in; /* safe: < than ZLIB_IO_MAX */ - - avail_in -= avail; - png_ptr->zstream.avail_in = avail; - - /* zlib OUTPUT BUFFER */ - avail_out += png_ptr->zstream.avail_out; /* not written last time */ - - avail = ZLIB_IO_MAX; /* maximum zlib can process */ - - if (output == NULL) - { - /* Reset the output buffer each time round if output is NULL and - * make available the full buffer, up to 'remaining_space' - */ - png_ptr->zstream.next_out = local_buffer; - if ((sizeof local_buffer) < avail) - avail = (sizeof local_buffer); - } - - if (avail_out < avail) - avail = (uInt)avail_out; /* safe: < ZLIB_IO_MAX */ - - png_ptr->zstream.avail_out = avail; - avail_out -= avail; - - /* zlib inflate call */ - /* In fact 'avail_out' may be 0 at this point, that happens at the end - * of the read when the final LZ end code was not passed at the end of - * the previous chunk of input data. Tell zlib if we have reached the - * end of the output buffer. - */ - ret = inflate(&png_ptr->zstream, avail_out > 0 ? Z_NO_FLUSH : - (finish ? Z_FINISH : Z_SYNC_FLUSH)); - } while (ret == Z_OK); - - /* For safety kill the local buffer pointer now */ - if (output == NULL) - png_ptr->zstream.next_out = NULL; - - /* Claw back the 'size' and 'remaining_space' byte counts. */ - avail_in += png_ptr->zstream.avail_in; - avail_out += png_ptr->zstream.avail_out; - - /* Update the input and output sizes; the updated values are the amount - * consumed or written, effectively the inverse of what zlib uses. - */ - if (avail_out > 0) - *output_size_ptr -= avail_out; - - if (avail_in > 0) - *input_size_ptr -= avail_in; - - /* Ensure png_ptr->zstream.msg is set (even in the success case!) */ - png_zstream_error(png_ptr, ret); - return ret; - } - - else - { - /* This is a bad internal error. The recovery assigns to the zstream msg - * pointer, which is not owned by the caller, but this is safe; it's only - * used on errors! - */ - png_ptr->zstream.msg = PNGZ_MSG_CAST("zstream unclaimed"); - return Z_STREAM_ERROR; - } -} - -/* - * Decompress trailing data in a chunk. The assumption is that read_buffer - * 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). - */ -static int -png_decompress_chunk(png_structrp png_ptr, - png_uint_32 chunklength, png_uint_32 prefix_size, - png_alloc_size_t *newlength /* must be initialized to the maximum! */, - int terminate /*add a '\0' to the end of the uncompressed data*/) -{ - /* TODO: implement different limits for different types of chunk. - * - * The caller supplies *newlength set to the maximum length of the - * uncompressed data, but this routine allocates space for the prefix and - * maybe a '\0' terminator too. We have to assume that 'prefix_size' is - * limited only by the maximum chunk size. - */ - png_alloc_size_t limit = PNG_SIZE_MAX; - -# ifdef PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED - if (png_ptr->user_chunk_malloc_max > 0 && - png_ptr->user_chunk_malloc_max < limit) - limit = png_ptr->user_chunk_malloc_max; -# elif PNG_USER_CHUNK_MALLOC_MAX > 0 - if (PNG_USER_CHUNK_MALLOC_MAX < limit) - limit = PNG_USER_CHUNK_MALLOC_MAX; -# endif - - if (limit >= prefix_size + (terminate != 0)) - { - int ret; - - limit -= prefix_size + (terminate != 0); - - if (limit < *newlength) - *newlength = limit; - - /* Now try to claim the stream. */ - ret = png_inflate_claim(png_ptr, png_ptr->chunk_name); - - if (ret == Z_OK) - { - png_uint_32 lzsize = chunklength - prefix_size; - - ret = png_inflate(png_ptr, png_ptr->chunk_name, 1/*finish*/, - /* input: */ png_ptr->read_buffer + prefix_size, &lzsize, - /* output: */ NULL, newlength); - - if (ret == Z_STREAM_END) - { - /* Use 'inflateReset' here, not 'inflateReset2' because this - * preserves the previously decided window size (otherwise it would - * be necessary to store the previous window size.) In practice - * this doesn't matter anyway, because png_inflate will call inflate - * with Z_FINISH in almost all cases, so the window will not be - * maintained. - */ - if (inflateReset(&png_ptr->zstream) == Z_OK) - { - /* Because of the limit checks above we know that the new, - * expanded, size will fit in a size_t (let alone an - * png_alloc_size_t). Use png_malloc_base here to avoid an - * extra OOM message. - */ - png_alloc_size_t new_size = *newlength; - png_alloc_size_t buffer_size = prefix_size + new_size + - (terminate != 0); - png_bytep text = png_voidcast(png_bytep, png_malloc_base(png_ptr, - buffer_size)); - - if (text != NULL) - { - ret = png_inflate(png_ptr, png_ptr->chunk_name, 1/*finish*/, - png_ptr->read_buffer + prefix_size, &lzsize, - text + prefix_size, newlength); - - if (ret == Z_STREAM_END) - { - if (new_size == *newlength) - { - if (terminate != 0) - text[prefix_size + *newlength] = 0; - - if (prefix_size > 0) - memcpy(text, png_ptr->read_buffer, prefix_size); - - { - png_bytep old_ptr = png_ptr->read_buffer; - - png_ptr->read_buffer = text; - png_ptr->read_buffer_size = buffer_size; - text = old_ptr; /* freed below */ - } - } - - else - { - /* The size changed on the second read, there can be no - * guarantee that anything is correct at this point. - * The 'msg' pointer has been set to "unexpected end of - * LZ stream", which is fine, but return an error code - * that the caller won't accept. - */ - ret = PNG_UNEXPECTED_ZLIB_RETURN; - } - } - - else if (ret == Z_OK) - ret = PNG_UNEXPECTED_ZLIB_RETURN; /* for safety */ - - /* Free the text pointer (this is the old read_buffer on - * success) - */ - png_free(png_ptr, text); - - /* This really is very benign, but it's still an error because - * the extra space may otherwise be used as a Trojan Horse. - */ - if (ret == Z_STREAM_END && - chunklength - prefix_size != lzsize) - png_chunk_benign_error(png_ptr, "extra compressed data"); - } - - else - { - /* Out of memory allocating the buffer */ - ret = Z_MEM_ERROR; - png_zstream_error(png_ptr, Z_MEM_ERROR); - } - } - - else - { - /* inflateReset failed, store the error message */ - png_zstream_error(png_ptr, ret); - - if (ret == Z_STREAM_END) - ret = PNG_UNEXPECTED_ZLIB_RETURN; - } - } - - else if (ret == Z_OK) - ret = PNG_UNEXPECTED_ZLIB_RETURN; - - /* Release the claimed stream */ - png_ptr->zowner = 0; - } - - else /* the claim failed */ if (ret == Z_STREAM_END) /* impossible! */ - ret = PNG_UNEXPECTED_ZLIB_RETURN; - - return ret; - } - - else - { - /* Application/configuration limits exceeded */ - png_zstream_error(png_ptr, Z_MEM_ERROR); - return Z_MEM_ERROR; - } -} -#endif /* PNG_READ_COMPRESSED_TEXT_SUPPORTED */ - -#ifdef PNG_READ_iCCP_SUPPORTED -/* Perform a partial read and decompress, producing 'avail_out' bytes and - * reading from the current chunk as required. - */ -static int -png_inflate_read(png_structrp png_ptr, png_bytep read_buffer, uInt read_size, - png_uint_32p chunk_bytes, png_bytep next_out, png_alloc_size_t *out_size, - int finish) -{ - if (png_ptr->zowner == png_ptr->chunk_name) - { - int ret; - - /* next_in and avail_in must have been initialized by the caller. */ - png_ptr->zstream.next_out = next_out; - png_ptr->zstream.avail_out = 0; /* set in the loop */ - - do - { - if (png_ptr->zstream.avail_in == 0) - { - if (read_size > *chunk_bytes) - read_size = (uInt)*chunk_bytes; - *chunk_bytes -= read_size; - - if (read_size > 0) - png_crc_read(png_ptr, read_buffer, read_size); - - png_ptr->zstream.next_in = read_buffer; - png_ptr->zstream.avail_in = read_size; - } - - if (png_ptr->zstream.avail_out == 0) - { - uInt avail = ZLIB_IO_MAX; - if (avail > *out_size) - avail = (uInt)*out_size; - *out_size -= avail; - - png_ptr->zstream.avail_out = avail; - } - - /* Use Z_SYNC_FLUSH when there is no more chunk data to ensure that all - * the available output is produced; this allows reading of truncated - * streams. - */ - ret = inflate(&png_ptr->zstream, - *chunk_bytes > 0 ? Z_NO_FLUSH : (finish ? Z_FINISH : Z_SYNC_FLUSH)); - } - while (ret == Z_OK && (*out_size > 0 || png_ptr->zstream.avail_out > 0)); - - *out_size += png_ptr->zstream.avail_out; - png_ptr->zstream.avail_out = 0; /* Should not be required, but is safe */ - - /* Ensure the error message pointer is always set: */ - png_zstream_error(png_ptr, ret); - return ret; - } - - else - { - png_ptr->zstream.msg = PNGZ_MSG_CAST("zstream unclaimed"); - return Z_STREAM_ERROR; - } -} -#endif - -/* Read and check the IDHR chunk */ -void /* PRIVATE */ -png_handle_IHDR(png_structrp png_ptr, png_inforp 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_chunk_error(png_ptr, "out of place"); - - /* Check the length */ - if (length != 13) - png_chunk_error(png_ptr, "invalid"); - - 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_structrp png_ptr, png_inforp 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_chunk_error(png_ptr, "missing IHDR"); - - /* Moved to before the 'after IDAT' check below because otherwise duplicate - * PLTE chunks are potentially ignored (the spec says there shall not be more - * than one PLTE, the error is not treated as benign, so this check trumps - * the requirement that PLTE appears before IDAT.) - */ - else if (png_ptr->mode & PNG_HAVE_PLTE) - png_chunk_error(png_ptr, "duplicate"); - - else if (png_ptr->mode & PNG_HAVE_IDAT) - { - /* This is benign because the non-benign error happened before, when an - * IDAT was encountered in a color-mapped image with no PLTE. - */ - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "out of place"); - return; - } - - png_ptr->mode |= PNG_HAVE_PLTE; - - if (!(png_ptr->color_type & PNG_COLOR_MASK_COLOR)) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "ignored in grayscale PNG"); - 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) - { - png_crc_finish(png_ptr, length); - - if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE) - png_chunk_benign_error(png_ptr, "invalid"); - - else - png_chunk_error(png_ptr, "invalid"); - - return; - } - - /* The cast is safe because 'length' is less than 3*PNG_MAX_PALETTE_LENGTH */ - 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). - * - * IMPLEMENTATION NOTE: this is only here because png_crc_finish uses the - * chunk type to determine whether to check the ancillary or the critical - * flags. - */ - if (!(png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_USE)) - { - if (png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN) - return; - - else - png_chunk_error(png_ptr, "CRC error"); - } - - /* 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 - - /* TODO: png_set_PLTE has the side effect of setting png_ptr->palette to its - * own copy of the palette. This has the side effect that when png_start_row - * is called (this happens after any call to png_read_update_info) the - * info_ptr palette gets changed. This is extremely unexpected and - * confusing. - * - * Fix this by not sharing the palette in this way. - */ - png_set_PLTE(png_ptr, info_ptr, palette, num); - - /* The three chunks, bKGD, hIST and tRNS *must* appear after PLTE and before - * IDAT. Prior to 1.6.0 this was not checked; instead the code merely - * checked the apparent validity of a tRNS chunk inserted before PLTE on a - * palette PNG. 1.6.0 attempts to rigorously follow the standard and - * therefore does a benign error if the erroneous condition is detected *and* - * cancels the tRNS if the benign error returns. The alternative is to - * amend the standard since it would be rather hypocritical of the standards - * maintainers to ignore it. - */ -#ifdef PNG_READ_tRNS_SUPPORTED - if (png_ptr->num_trans > 0 || - (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS) != 0)) - { - /* Cancel this because otherwise it would be used if the transforms - * require it. Don't cancel the 'valid' flag because this would prevent - * detection of duplicate chunks. - */ - png_ptr->num_trans = 0; - - if (info_ptr != NULL) - info_ptr->num_trans = 0; - - png_chunk_benign_error(png_ptr, "tRNS must be after"); - } -#endif - -#ifdef PNG_READ_hIST_SUPPORTED - if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST) != 0) - png_chunk_benign_error(png_ptr, "hIST must be after"); -#endif - -#ifdef PNG_READ_bKGD_SUPPORTED - if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD) != 0) - png_chunk_benign_error(png_ptr, "bKGD must be after"); -#endif -} - -void /* PRIVATE */ -png_handle_IEND(png_structrp png_ptr, png_inforp 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_chunk_error(png_ptr, "out of place"); - - png_ptr->mode |= (PNG_AFTER_IDAT | PNG_HAVE_IEND); - - png_crc_finish(png_ptr, length); - - if (length != 0) - png_chunk_benign_error(png_ptr, "invalid"); - - PNG_UNUSED(info_ptr) -} - -#ifdef PNG_READ_gAMA_SUPPORTED -void /* PRIVATE */ -png_handle_gAMA(png_structrp png_ptr, png_inforp 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_chunk_error(png_ptr, "missing IHDR"); - - else if (png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "out of place"); - return; - } - - if (length != 4) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "invalid"); - return; - } - - png_crc_read(png_ptr, buf, 4); - - if (png_crc_finish(png_ptr, 0)) - return; - - igamma = png_get_fixed_point(NULL, buf); - - png_colorspace_set_gamma(png_ptr, &png_ptr->colorspace, igamma); - png_colorspace_sync(png_ptr, info_ptr); -} -#endif - -#ifdef PNG_READ_sBIT_SUPPORTED -void /* PRIVATE */ -png_handle_sBIT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) -{ - unsigned int truelen, i; - png_byte sample_depth; - png_byte buf[4]; - - png_debug(1, "in png_handle_sBIT"); - - if (!(png_ptr->mode & PNG_HAVE_IHDR)) - png_chunk_error(png_ptr, "missing IHDR"); - - else if (png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "out of place"); - return; - } - - if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sBIT)) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "duplicate"); - return; - } - - if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) - { - truelen = 3; - sample_depth = 8; - } - - else - { - truelen = png_ptr->channels; - sample_depth = png_ptr->bit_depth; - } - - if (length != truelen || length > 4) - { - png_chunk_benign_error(png_ptr, "invalid"); - png_crc_finish(png_ptr, length); - return; - } - - buf[0] = buf[1] = buf[2] = buf[3] = sample_depth; - png_crc_read(png_ptr, buf, truelen); - - if (png_crc_finish(png_ptr, 0)) - return; - - for (i=0; i<truelen; ++i) - if (buf[i] == 0 || buf[i] > sample_depth) - { - png_chunk_benign_error(png_ptr, "invalid"); - 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_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) -{ - png_byte buf[32]; - png_xy xy; - - png_debug(1, "in png_handle_cHRM"); - - if (!(png_ptr->mode & PNG_HAVE_IHDR)) - png_chunk_error(png_ptr, "missing IHDR"); - - else if (png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "out of place"); - return; - } - - if (length != 32) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "invalid"); - return; - } - - png_crc_read(png_ptr, buf, 32); - - if (png_crc_finish(png_ptr, 0)) - return; - - xy.whitex = png_get_fixed_point(NULL, buf); - xy.whitey = png_get_fixed_point(NULL, buf + 4); - xy.redx = png_get_fixed_point(NULL, buf + 8); - xy.redy = png_get_fixed_point(NULL, buf + 12); - xy.greenx = png_get_fixed_point(NULL, buf + 16); - xy.greeny = png_get_fixed_point(NULL, buf + 20); - xy.bluex = png_get_fixed_point(NULL, buf + 24); - xy.bluey = png_get_fixed_point(NULL, buf + 28); - - if (xy.whitex == PNG_FIXED_ERROR || - xy.whitey == PNG_FIXED_ERROR || - xy.redx == PNG_FIXED_ERROR || - xy.redy == PNG_FIXED_ERROR || - xy.greenx == PNG_FIXED_ERROR || - xy.greeny == PNG_FIXED_ERROR || - xy.bluex == PNG_FIXED_ERROR || - xy.bluey == PNG_FIXED_ERROR) - { - png_chunk_benign_error(png_ptr, "invalid values"); - return; - } - - /* If a colorspace error has already been output skip this chunk */ - if (png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) - return; - - if (png_ptr->colorspace.flags & PNG_COLORSPACE_FROM_cHRM) - { - png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID; - png_colorspace_sync(png_ptr, info_ptr); - png_chunk_benign_error(png_ptr, "duplicate"); - return; - } - - png_ptr->colorspace.flags |= PNG_COLORSPACE_FROM_cHRM; - (void)png_colorspace_set_chromaticities(png_ptr, &png_ptr->colorspace, &xy, - 1/*prefer cHRM values*/); - png_colorspace_sync(png_ptr, info_ptr); -} -#endif - -#ifdef PNG_READ_sRGB_SUPPORTED -void /* PRIVATE */ -png_handle_sRGB(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) -{ - png_byte intent; - - png_debug(1, "in png_handle_sRGB"); - - if (!(png_ptr->mode & PNG_HAVE_IHDR)) - png_chunk_error(png_ptr, "missing IHDR"); - - else if (png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "out of place"); - return; - } - - if (length != 1) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "invalid"); - return; - } - - png_crc_read(png_ptr, &intent, 1); - - if (png_crc_finish(png_ptr, 0)) - return; - - /* If a colorspace error has already been output skip this chunk */ - if (png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) - return; - - /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect - * this. - */ - if (png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_INTENT) - { - png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID; - png_colorspace_sync(png_ptr, info_ptr); - png_chunk_benign_error(png_ptr, "too many profiles"); - return; - } - - (void)png_colorspace_set_sRGB(png_ptr, &png_ptr->colorspace, intent); - png_colorspace_sync(png_ptr, info_ptr); -} -#endif /* PNG_READ_sRGB_SUPPORTED */ - -#ifdef PNG_READ_iCCP_SUPPORTED -void /* PRIVATE */ -png_handle_iCCP(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) -/* Note: this does not properly handle profiles that are > 64K under DOS */ -{ - png_const_charp errmsg = NULL; /* error message output, or no error */ - int finished = 0; /* crc checked */ - - png_debug(1, "in png_handle_iCCP"); - - if (!(png_ptr->mode & PNG_HAVE_IHDR)) - png_chunk_error(png_ptr, "missing IHDR"); - - else if (png_ptr->mode & (PNG_HAVE_IDAT|PNG_HAVE_PLTE)) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "out of place"); - return; - } - - /* Consistent with all the above colorspace handling an obviously *invalid* - * chunk is just ignored, so does not invalidate the color space. An - * alternative is to set the 'invalid' flags at the start of this routine - * and only clear them in they were not set before and all the tests pass. - * The minimum 'deflate' stream is assumed to be just the 2 byte header and 4 - * byte checksum. The keyword must be one character and there is a - * terminator (0) byte and the compression method. - */ - if (length < 9) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "too short"); - return; - } - - /* If a colorspace error has already been output skip this chunk */ - if (png_ptr->colorspace.flags & PNG_COLORSPACE_INVALID) - { - png_crc_finish(png_ptr, length); - return; - } - - /* Only one sRGB or iCCP chunk is allowed, use the HAVE_INTENT flag to detect - * this. - */ - if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_INTENT) == 0) - { - uInt read_length, keyword_length; - char keyword[81]; - - /* Find the keyword; the keyword plus separator and compression method - * bytes can be at most 81 characters long. - */ - read_length = 81; /* maximum */ - if (read_length > length) - read_length = (uInt)length; - - png_crc_read(png_ptr, (png_bytep)keyword, read_length); - length -= read_length; - - keyword_length = 0; - while (keyword_length < 80 && keyword_length < read_length && - keyword[keyword_length] != 0) - ++keyword_length; - - /* TODO: make the keyword checking common */ - if (keyword_length >= 1 && keyword_length <= 79) - { - /* We only understand '0' compression - deflate - so if we get a - * different value we can't safely decode the chunk. - */ - if (keyword_length+1 < read_length && - keyword[keyword_length+1] == PNG_COMPRESSION_TYPE_BASE) - { - read_length -= keyword_length+2; - - if (png_inflate_claim(png_ptr, png_iCCP) == Z_OK) - { - Byte profile_header[132]; - Byte local_buffer[PNG_INFLATE_BUF_SIZE]; - png_alloc_size_t size = (sizeof profile_header); - - png_ptr->zstream.next_in = (Bytef*)keyword + (keyword_length+2); - png_ptr->zstream.avail_in = read_length; - (void)png_inflate_read(png_ptr, local_buffer, - (sizeof local_buffer), &length, profile_header, &size, - 0/*finish: don't, because the output is too small*/); - - if (size == 0) - { - /* We have the ICC profile header; do the basic header checks. - */ - const png_uint_32 profile_length = - png_get_uint_32(profile_header); - - if (png_icc_check_length(png_ptr, &png_ptr->colorspace, - keyword, profile_length)) - { - /* The length is apparently ok, so we can check the 132 - * byte header. - */ - if (png_icc_check_header(png_ptr, &png_ptr->colorspace, - keyword, profile_length, profile_header, - png_ptr->color_type)) - { - /* Now read the tag table; a variable size buffer is - * needed at this point, allocate one for the whole - * profile. The header check has already validated - * that none of these stuff will overflow. - */ - const png_uint_32 tag_count = png_get_uint_32( - profile_header+128); - png_bytep profile = png_read_buffer(png_ptr, - profile_length, 2/*silent*/); - - if (profile != NULL) - { - memcpy(profile, profile_header, - (sizeof profile_header)); - - size = 12 * tag_count; - - (void)png_inflate_read(png_ptr, local_buffer, - (sizeof local_buffer), &length, - profile + (sizeof profile_header), &size, 0); - - /* Still expect a buffer error because we expect - * there to be some tag data! - */ - if (size == 0) - { - if (png_icc_check_tag_table(png_ptr, - &png_ptr->colorspace, keyword, profile_length, - profile)) - { - /* The profile has been validated for basic - * security issues, so read the whole thing in. - */ - size = profile_length - (sizeof profile_header) - - 12 * tag_count; - - (void)png_inflate_read(png_ptr, local_buffer, - (sizeof local_buffer), &length, - profile + (sizeof profile_header) + - 12 * tag_count, &size, 1/*finish*/); - - if (length > 0 && !(png_ptr->flags & - PNG_FLAG_BENIGN_ERRORS_WARN)) - errmsg = "extra compressed data"; - - /* But otherwise allow extra data: */ - else if (size == 0) - { - if (length > 0) - { - /* This can be handled completely, so - * keep going. - */ - png_chunk_warning(png_ptr, - "extra compressed data"); - } - - png_crc_finish(png_ptr, length); - finished = 1; - -# ifdef PNG_sRGB_SUPPORTED - /* Check for a match against sRGB */ - png_icc_set_sRGB(png_ptr, - &png_ptr->colorspace, profile, - png_ptr->zstream.adler); -# endif - - /* Steal the profile for info_ptr. */ - if (info_ptr != NULL) - { - png_free_data(png_ptr, info_ptr, - PNG_FREE_ICCP, 0); - - info_ptr->iccp_name = png_voidcast(char*, - png_malloc_base(png_ptr, - keyword_length+1)); - if (info_ptr->iccp_name != NULL) - { - memcpy(info_ptr->iccp_name, keyword, - keyword_length+1); - info_ptr->iccp_proflen = - profile_length; - info_ptr->iccp_profile = profile; - png_ptr->read_buffer = NULL; /*steal*/ - info_ptr->free_me |= PNG_FREE_ICCP; - info_ptr->valid |= PNG_INFO_iCCP; - } - - else - { - png_ptr->colorspace.flags |= - PNG_COLORSPACE_INVALID; - errmsg = "out of memory"; - } - } - - /* else the profile remains in the read - * buffer which gets reused for subsequent - * chunks. - */ - - if (info_ptr != NULL) - png_colorspace_sync(png_ptr, info_ptr); - - if (errmsg == NULL) - { - png_ptr->zowner = 0; - return; - } - } - - else if (size > 0) - errmsg = "truncated"; - - else - errmsg = png_ptr->zstream.msg; - } - - /* else png_icc_check_tag_table output an error */ - } - - else /* profile truncated */ - errmsg = png_ptr->zstream.msg; - } - - else - errmsg = "out of memory"; - } - - /* else png_icc_check_header output an error */ - } - - /* else png_icc_check_length output an error */ - } - - else /* profile truncated */ - errmsg = png_ptr->zstream.msg; - - /* Release the stream */ - png_ptr->zowner = 0; - } - - else /* png_inflate_claim failed */ - errmsg = png_ptr->zstream.msg; - } - - else - errmsg = "bad compression method"; /* or missing */ - } - - else - errmsg = "bad keyword"; - } - - else - errmsg = "too many profiles"; - - /* Failure: the reason is in 'errmsg' */ - if (finished == 0) - png_crc_finish(png_ptr, length); - - png_ptr->colorspace.flags |= PNG_COLORSPACE_INVALID; - png_colorspace_sync(png_ptr, info_ptr); - if (errmsg != NULL) /* else already output */ - png_chunk_benign_error(png_ptr, errmsg); -} -#endif /* PNG_READ_iCCP_SUPPORTED */ - -#ifdef PNG_READ_sPLT_SUPPORTED -void /* PRIVATE */ -png_handle_sPLT(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) -/* Note: this does not properly handle chunks that are > 64K under DOS */ -{ - png_bytep entry_start, buffer; - png_sPLT_t new_palette; - png_sPLT_entryp pp; - png_uint_32 data_length; - int entry_size, i; - png_uint_32 skip = 0; - 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_chunk_error(png_ptr, "missing IHDR"); - - else if (png_ptr->mode & PNG_HAVE_IDAT) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "out of place"); - return; - } - -#ifdef PNG_MAX_MALLOC_64K - if (length > 65535U) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "too large to fit in memory"); - return; - } -#endif - - buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/); - if (buffer == NULL) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "out of memory"); - return; - } - - - /* 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. - */ - png_crc_read(png_ptr, buffer, length); - - if (png_crc_finish(png_ptr, skip)) - return; - - buffer[length] = 0; - - for (entry_start = buffer; *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 > buffer + length - 2) - { - 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. - */ - data_length = length - (png_uint_32)(entry_start - buffer); - - /* Integrity-check the data length */ - if (data_length % entry_size) - { - png_warning(png_ptr, "sPLT chunk has bad length"); - return; - } - - dl = (png_int_32)(data_length / entry_size); - max_dl = PNG_SIZE_MAX / (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 * (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_charp)buffer; - - png_set_sPLT(png_ptr, info_ptr, &new_palette, 1); - - png_free(png_ptr, new_palette.entries); -} -#endif /* PNG_READ_sPLT_SUPPORTED */ - -#ifdef PNG_READ_tRNS_SUPPORTED -void /* PRIVATE */ -png_handle_tRNS(png_structrp png_ptr, png_inforp 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_chunk_error(png_ptr, "missing IHDR"); - - else if (png_ptr->mode & PNG_HAVE_IDAT) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "out of place"); - return; - } - - else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS)) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "duplicate"); - return; - } - - if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY) - { - png_byte buf[2]; - - if (length != 2) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "invalid"); - 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_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "invalid"); - return; - } - - png_crc_read(png_ptr, buf, 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)) - { - /* TODO: is this actually an error in the ISO spec? */ - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "out of place"); - return; - } - - if (length > png_ptr->num_palette || length > PNG_MAX_PALETTE_LENGTH || - length == 0) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "invalid"); - return; - } - - png_crc_read(png_ptr, readbuf, length); - png_ptr->num_trans = (png_uint_16)length; - } - - else - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "invalid with alpha channel"); - return; - } - - if (png_crc_finish(png_ptr, 0)) - { - png_ptr->num_trans = 0; - return; - } - - /* TODO: this is a horrible side effect in the palette case because the - * png_struct ends up with a pointer to the tRNS buffer owned by the - * png_info. Fix this. - */ - 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_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) -{ - unsigned int truelen; - png_byte buf[6]; - png_color_16 background; - - png_debug(1, "in png_handle_bKGD"); - - if (!(png_ptr->mode & PNG_HAVE_IHDR)) - png_chunk_error(png_ptr, "missing IHDR"); - - else if ((png_ptr->mode & PNG_HAVE_IDAT) || - (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE && - !(png_ptr->mode & PNG_HAVE_PLTE))) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "out of place"); - return; - } - - else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD)) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "duplicate"); - 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_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "invalid"); - 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_chunk_benign_error(png_ptr, "invalid index"); - 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_structrp png_ptr, png_inforp 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_chunk_error(png_ptr, "missing IHDR"); - - else if ((png_ptr->mode & PNG_HAVE_IDAT) || !(png_ptr->mode & PNG_HAVE_PLTE)) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "out of place"); - return; - } - - else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST)) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "duplicate"); - return; - } - - num = length / 2 ; - - if (num != png_ptr->num_palette || num > PNG_MAX_PALETTE_LENGTH) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "invalid"); - return; - } - - for (i = 0; i < num; i++) - { - png_byte buf[2]; - - png_crc_read(png_ptr, buf, 2); - readbuf[i] = png_get_uint_16(buf); - } - - if (png_crc_finish(png_ptr, 0)) - return; - - png_set_hIST(png_ptr, info_ptr, readbuf); -} -#endif - -#ifdef PNG_READ_pHYs_SUPPORTED -void /* PRIVATE */ -png_handle_pHYs(png_structrp png_ptr, png_inforp 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_chunk_error(png_ptr, "missing IHDR"); - - else if (png_ptr->mode & PNG_HAVE_IDAT) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "out of place"); - return; - } - - else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs)) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "duplicate"); - return; - } - - if (length != 9) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "invalid"); - 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_structrp png_ptr, png_inforp 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_chunk_error(png_ptr, "missing IHDR"); - - else if (png_ptr->mode & PNG_HAVE_IDAT) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "out of place"); - return; - } - - else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs)) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "duplicate"); - return; - } - - if (length != 9) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "invalid"); - 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_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) -{ - png_int_32 X0, X1; - png_byte type, nparams; - png_bytep buffer, buf, units, endptr; - png_charpp params; - int i; - - png_debug(1, "in png_handle_pCAL"); - - if (!(png_ptr->mode & PNG_HAVE_IHDR)) - png_chunk_error(png_ptr, "missing IHDR"); - - else if (png_ptr->mode & PNG_HAVE_IDAT) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "out of place"); - return; - } - - else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pCAL)) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "duplicate"); - return; - } - - png_debug1(2, "Allocating and reading pCAL chunk data (%u bytes)", - length + 1); - - buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/); - - if (buffer == NULL) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "out of memory"); - return; - } - - png_crc_read(png_ptr, buffer, length); - - if (png_crc_finish(png_ptr, 0)) - return; - - buffer[length] = 0; /* Null terminate the last string */ - - png_debug(3, "Finding end of pCAL purpose string"); - for (buf = buffer; *buf; buf++) - /* Empty loop */ ; - - endptr = buffer + length; - - /* We need to have at least 12 bytes after the purpose string - * in order to get the parameter information. - */ - if (endptr <= buf + 12) - { - png_chunk_benign_error(png_ptr, "invalid"); - 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_chunk_benign_error(png_ptr, "invalid parameter count"); - return; - } - - else if (type >= PNG_EQUATION_LAST) - { - png_chunk_benign_error(png_ptr, "unrecognized equation type"); - } - - for (buf = units; *buf; buf++) - /* Empty loop to move past the units string. */ ; - - png_debug(3, "Allocating pCAL parameters array"); - - params = png_voidcast(png_charpp, png_malloc_warn(png_ptr, - nparams * (sizeof (png_charp)))); - - if (params == NULL) - { - png_chunk_benign_error(png_ptr, "out of memory"); - return; - } - - /* Get pointers to the start of each parameter string. */ - for (i = 0; i < nparams; i++) - { - buf++; /* Skip the null string terminator from previous parameter. */ - - png_debug1(3, "Reading pCAL parameter %d", i); - - for (params[i] = (png_charp)buf; buf <= endptr && *buf != 0; buf++) - /* Empty loop to move past each parameter string */ ; - - /* Make sure we haven't run out of data yet */ - if (buf > endptr) - { - png_free(png_ptr, params); - png_chunk_benign_error(png_ptr, "invalid data"); - return; - } - } - - png_set_pCAL(png_ptr, info_ptr, (png_charp)buffer, X0, X1, type, nparams, - (png_charp)units, params); - - png_free(png_ptr, params); -} -#endif - -#ifdef PNG_READ_sCAL_SUPPORTED -/* Read the sCAL chunk */ -void /* PRIVATE */ -png_handle_sCAL(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) -{ - png_bytep buffer; - png_size_t i; - int state; - - png_debug(1, "in png_handle_sCAL"); - - if (!(png_ptr->mode & PNG_HAVE_IHDR)) - png_chunk_error(png_ptr, "missing IHDR"); - - else if (png_ptr->mode & PNG_HAVE_IDAT) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "out of place"); - return; - } - - else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sCAL)) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "duplicate"); - return; - } - - /* Need unit type, width, \0, height: minimum 4 bytes */ - else if (length < 4) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "invalid"); - return; - } - - png_debug1(2, "Allocating and reading sCAL chunk data (%u bytes)", - length + 1); - - buffer = png_read_buffer(png_ptr, length+1, 2/*silent*/); - - if (buffer == NULL) - { - png_chunk_benign_error(png_ptr, "out of memory"); - png_crc_finish(png_ptr, length); - return; - } - - png_crc_read(png_ptr, buffer, length); - buffer[length] = 0; /* Null terminate the last string */ - - if (png_crc_finish(png_ptr, 0)) - return; - - /* Validate the unit. */ - if (buffer[0] != 1 && buffer[0] != 2) - { - png_chunk_benign_error(png_ptr, "invalid unit"); - 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_const_charp)buffer, length, &state, &i) || - i >= length || buffer[i++] != 0) - png_chunk_benign_error(png_ptr, "bad width format"); - - else if (!PNG_FP_IS_POSITIVE(state)) - png_chunk_benign_error(png_ptr, "non-positive width"); - - else - { - png_size_t heighti = i; - - state = 0; - if (!png_check_fp_number((png_const_charp)buffer, length, &state, &i) || - i != length) - png_chunk_benign_error(png_ptr, "bad height format"); - - else if (!PNG_FP_IS_POSITIVE(state)) - png_chunk_benign_error(png_ptr, "non-positive height"); - - else - /* This is the (only) success case. */ - png_set_sCAL_s(png_ptr, info_ptr, buffer[0], - (png_charp)buffer+1, (png_charp)buffer+heighti); - } -} -#endif - -#ifdef PNG_READ_tIME_SUPPORTED -void /* PRIVATE */ -png_handle_tIME(png_structrp png_ptr, png_inforp 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_chunk_error(png_ptr, "missing IHDR"); - - else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tIME)) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "duplicate"); - return; - } - - if (png_ptr->mode & PNG_HAVE_IDAT) - png_ptr->mode |= PNG_AFTER_IDAT; - - if (length != 7) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "invalid"); - 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_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) -{ - png_text text_info; - png_bytep buffer; - png_charp key; - png_charp text; - png_uint_32 skip = 0; - - 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_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "no space in chunk cache"); - return; - } - } -#endif - - if (!(png_ptr->mode & PNG_HAVE_IHDR)) - png_chunk_error(png_ptr, "missing IHDR"); - - if (png_ptr->mode & PNG_HAVE_IDAT) - png_ptr->mode |= PNG_AFTER_IDAT; - -#ifdef PNG_MAX_MALLOC_64K - if (length > 65535U) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "too large to fit in memory"); - return; - } -#endif - - buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/); - - if (buffer == NULL) - { - png_chunk_benign_error(png_ptr, "out of memory"); - return; - } - - png_crc_read(png_ptr, buffer, length); - - if (png_crc_finish(png_ptr, skip)) - return; - - key = (png_charp)buffer; - key[length] = 0; - - for (text = key; *text; text++) - /* Empty loop to find end of key */ ; - - if (text != key + length) - text++; - - text_info.compression = PNG_TEXT_COMPRESSION_NONE; - text_info.key = key; - text_info.lang = NULL; - text_info.lang_key = NULL; - text_info.itxt_length = 0; - text_info.text = text; - text_info.text_length = strlen(text); - - if (png_set_text_2(png_ptr, info_ptr, &text_info, 1)) - 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_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) -{ - png_const_charp errmsg = NULL; - png_bytep buffer; - png_uint_32 keyword_length; - - 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_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "no space in chunk cache"); - return; - } - } -#endif - - if (!(png_ptr->mode & PNG_HAVE_IHDR)) - png_chunk_error(png_ptr, "missing IHDR"); - - if (png_ptr->mode & PNG_HAVE_IDAT) - png_ptr->mode |= PNG_AFTER_IDAT; - - buffer = png_read_buffer(png_ptr, length, 2/*silent*/); - - if (buffer == NULL) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "out of memory"); - return; - } - - png_crc_read(png_ptr, buffer, length); - - if (png_crc_finish(png_ptr, 0)) - return; - - /* TODO: also check that the keyword contents match the spec! */ - for (keyword_length = 0; - keyword_length < length && buffer[keyword_length] != 0; - ++keyword_length) - /* Empty loop to find end of name */ ; - - if (keyword_length > 79 || keyword_length < 1) - errmsg = "bad keyword"; - - /* zTXt must have some LZ data after the keyword, although it may expand to - * zero bytes; we need a '\0' at the end of the keyword, the compression type - * then the LZ data: - */ - else if (keyword_length + 3 > length) - errmsg = "truncated"; - - else if (buffer[keyword_length+1] != PNG_COMPRESSION_TYPE_BASE) - errmsg = "unknown compression type"; - - else - { - png_alloc_size_t uncompressed_length = PNG_SIZE_MAX; - - /* TODO: at present png_decompress_chunk imposes a single application - * level memory limit, this should be split to different values for iCCP - * and text chunks. - */ - if (png_decompress_chunk(png_ptr, length, keyword_length+2, - &uncompressed_length, 1/*terminate*/) == Z_STREAM_END) - { - png_text text; - - /* It worked; png_ptr->read_buffer now looks like a tEXt chunk except - * for the extra compression type byte and the fact that it isn't - * necessarily '\0' terminated. - */ - buffer = png_ptr->read_buffer; - buffer[uncompressed_length+(keyword_length+2)] = 0; - - text.compression = PNG_TEXT_COMPRESSION_zTXt; - text.key = (png_charp)buffer; - text.text = (png_charp)(buffer + keyword_length+2); - text.text_length = uncompressed_length; - text.itxt_length = 0; - text.lang = NULL; - text.lang_key = NULL; - - if (png_set_text_2(png_ptr, info_ptr, &text, 1)) - errmsg = "insufficient memory"; - } - - else - errmsg = png_ptr->zstream.msg; - } - - if (errmsg != NULL) - png_chunk_benign_error(png_ptr, errmsg); -} -#endif - -#ifdef PNG_READ_iTXt_SUPPORTED -/* Note: this does not correctly handle chunks that are > 64K under DOS */ -void /* PRIVATE */ -png_handle_iTXt(png_structrp png_ptr, png_inforp info_ptr, png_uint_32 length) -{ - png_const_charp errmsg = NULL; - png_bytep buffer; - png_uint_32 prefix_length; - - 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_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "no space in chunk cache"); - return; - } - } -#endif - - if (!(png_ptr->mode & PNG_HAVE_IHDR)) - png_chunk_error(png_ptr, "missing IHDR"); - - if (png_ptr->mode & PNG_HAVE_IDAT) - png_ptr->mode |= PNG_AFTER_IDAT; - - buffer = png_read_buffer(png_ptr, length+1, 1/*warn*/); - - if (buffer == NULL) - { - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "out of memory"); - return; - } - - png_crc_read(png_ptr, buffer, length); - - if (png_crc_finish(png_ptr, 0)) - return; - - /* First the keyword. */ - for (prefix_length=0; - prefix_length < length && buffer[prefix_length] != 0; - ++prefix_length) - /* Empty loop */ ; - - /* Perform a basic check on the keyword length here. */ - if (prefix_length > 79 || prefix_length < 1) - errmsg = "bad keyword"; - - /* Expect keyword, compression flag, compression type, language, translated - * keyword (both may be empty but are 0 terminated) then the text, which may - * be empty. - */ - else if (prefix_length + 5 > length) - errmsg = "truncated"; - - else if (buffer[prefix_length+1] == 0 || - (buffer[prefix_length+1] == 1 && - buffer[prefix_length+2] == PNG_COMPRESSION_TYPE_BASE)) - { - int compressed = buffer[prefix_length+1] != 0; - png_uint_32 language_offset, translated_keyword_offset; - png_alloc_size_t uncompressed_length = 0; - - /* Now the language tag */ - prefix_length += 3; - language_offset = prefix_length; - - for (; prefix_length < length && buffer[prefix_length] != 0; - ++prefix_length) - /* Empty loop */ ; - - /* WARNING: the length may be invalid here, this is checked below. */ - translated_keyword_offset = ++prefix_length; - - for (; prefix_length < length && buffer[prefix_length] != 0; - ++prefix_length) - /* Empty loop */ ; - - /* prefix_length should now be at the trailing '\0' of the translated - * keyword, but it may already be over the end. None of this arithmetic - * can overflow because chunks are at most 2^31 bytes long, but on 16-bit - * systems the available allocaton may overflow. - */ - ++prefix_length; - - if (!compressed && prefix_length <= length) - uncompressed_length = length - prefix_length; - - else if (compressed && prefix_length < length) - { - uncompressed_length = PNG_SIZE_MAX; - - /* TODO: at present png_decompress_chunk imposes a single application - * level memory limit, this should be split to different values for - * iCCP and text chunks. - */ - if (png_decompress_chunk(png_ptr, length, prefix_length, - &uncompressed_length, 1/*terminate*/) == Z_STREAM_END) - buffer = png_ptr->read_buffer; - - else - errmsg = png_ptr->zstream.msg; - } - - else - errmsg = "truncated"; - - if (errmsg == NULL) - { - png_text text; - - buffer[uncompressed_length+prefix_length] = 0; - - if (compressed != 0) - text.compression = PNG_ITXT_COMPRESSION_NONE; - - else - text.compression = PNG_ITXT_COMPRESSION_zTXt; - - text.key = (png_charp)buffer; - text.lang = (png_charp)buffer + language_offset; - text.lang_key = (png_charp)buffer + translated_keyword_offset; - text.text = (png_charp)buffer + prefix_length; - text.text_length = 0; - text.itxt_length = uncompressed_length; - - if (png_set_text_2(png_ptr, info_ptr, &text, 1)) - errmsg = "insufficient memory"; - } - } - - else - errmsg = "bad compression info"; - - if (errmsg != NULL) - png_chunk_benign_error(png_ptr, errmsg); -} -#endif - -#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED -/* Utility function for png_handle_unknown; set up png_ptr::unknown_chunk */ -static int -png_cache_unknown_chunk(png_structrp png_ptr, png_uint_32 length) -{ - png_alloc_size_t limit = PNG_SIZE_MAX; - - if (png_ptr->unknown_chunk.data != NULL) - { - png_free(png_ptr, png_ptr->unknown_chunk.data); - png_ptr->unknown_chunk.data = NULL; - } - -# ifdef PNG_SET_CHUNK_MALLOC_LIMIT_SUPPORTED - if (png_ptr->user_chunk_malloc_max > 0 && - png_ptr->user_chunk_malloc_max < limit) - limit = png_ptr->user_chunk_malloc_max; - -# elif PNG_USER_CHUNK_MALLOC_MAX > 0 - if (PNG_USER_CHUNK_MALLOC_MAX < limit) - limit = PNG_USER_CHUNK_MALLOC_MAX; -# endif - - if (length <= limit) - { - PNG_CSTRING_FROM_CHUNK(png_ptr->unknown_chunk.name, png_ptr->chunk_name); - /* The following is safe because of the PNG_SIZE_MAX init above */ - png_ptr->unknown_chunk.size = (png_size_t)length/*SAFE*/; - /* 'mode' is a flag array, only the bottom four bits matter here */ - png_ptr->unknown_chunk.location = (png_byte)png_ptr->mode/*SAFE*/; - - if (length == 0) - png_ptr->unknown_chunk.data = NULL; - - else - { - /* Do a 'warn' here - it is handled below. */ - png_ptr->unknown_chunk.data = png_voidcast(png_bytep, - png_malloc_warn(png_ptr, length)); - } - } - - if (png_ptr->unknown_chunk.data == NULL && length > 0) - { - /* This is benign because we clean up correctly */ - png_crc_finish(png_ptr, length); - png_chunk_benign_error(png_ptr, "unknown chunk exceeds memory limits"); - return 0; - } - - else - { - if (length > 0) - png_crc_read(png_ptr, png_ptr->unknown_chunk.data, length); - png_crc_finish(png_ptr, 0); - return 1; - } -} -#endif /* PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */ - -/* Handle an unknown, or known but disabled, chunk */ -void /* PRIVATE */ -png_handle_unknown(png_structrp png_ptr, png_inforp info_ptr, - png_uint_32 length, int keep) -{ - int handled = 0; /* the chunk was handled */ - - png_debug(1, "in png_handle_unknown"); - -#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED - /* NOTE: this code is based on the code in libpng-1.4.12 except for fixing - * the bug which meant that setting a non-default behavior for a specific - * chunk would be ignored (the default was always used unless a user - * callback was installed). - * - * 'keep' is the value from the png_chunk_unknown_handling, the setting for - * this specific chunk_name, if PNG_HANDLE_AS_UNKNOWN_SUPPORTED, if not it - * will always be PNG_HANDLE_CHUNK_AS_DEFAULT and it needs to be set here. - * This is just an optimization to avoid multiple calls to the lookup - * function. - */ -# ifndef PNG_HANDLE_AS_UNKNOWN_SUPPORTED -# ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED - keep = png_chunk_unknown_handling(png_ptr, png_ptr->chunk_name); -# endif -# endif - - /* One of the following methods will read the chunk or skip it (at least one - * of these is always defined because this is the only way to switch on - * PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) - */ -# ifdef PNG_READ_USER_CHUNKS_SUPPORTED - /* The user callback takes precedence over the chunk keep value, but the - * keep value is still required to validate a save of a critical chunk. - */ - if (png_ptr->read_user_chunk_fn != NULL) - { - if (png_cache_unknown_chunk(png_ptr, length)) - { - /* Callback to user unknown chunk handler */ - int ret = (*(png_ptr->read_user_chunk_fn))(png_ptr, - &png_ptr->unknown_chunk); - - /* ret is: - * negative: An error occured, png_chunk_error will be called. - * zero: The chunk was not handled, the chunk will be discarded - * unless png_set_keep_unknown_chunks has been used to set - * a 'keep' behavior for this particular chunk, in which - * case that will be used. A critical chunk will cause an - * error at this point unless it is to be saved. - * positive: The chunk was handled, libpng will ignore/discard it. - */ - if (ret < 0) - png_chunk_error(png_ptr, "error in user chunk"); - - else if (ret == 0) - { - /* If the keep value is 'default' or 'never' override it, but - * still error out on critical chunks unless the keep value is - * 'always' While this is weird it is the behavior in 1.4.12. - * A possible improvement would be to obey the value set for the - * chunk, but this would be an API change that would probably - * damage some applications. - * - * The png_app_warning below catches the case that matters, where - * the application has not set specific save or ignore for this - * chunk or global save or ignore. - */ - if (keep < PNG_HANDLE_CHUNK_IF_SAFE) - { -# ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED - if (png_ptr->unknown_default < PNG_HANDLE_CHUNK_IF_SAFE) - { - png_chunk_warning(png_ptr, "Saving unknown chunk:"); - png_app_warning(png_ptr, - "forcing save of an unhandled chunk;" - " please call png_set_keep_unknown_chunks"); - /* with keep = PNG_HANDLE_CHUNK_IF_SAFE */ - } -# endif - keep = PNG_HANDLE_CHUNK_IF_SAFE; - } - } - - else /* chunk was handled */ - { - handled = 1; - /* Critical chunks can be safely discarded at this point. */ - keep = PNG_HANDLE_CHUNK_NEVER; - } - } - - else - keep = PNG_HANDLE_CHUNK_NEVER; /* insufficient memory */ - } - - else - /* Use the SAVE_UNKNOWN_CHUNKS code or skip the chunk */ -# endif /* PNG_READ_USER_CHUNKS_SUPPORTED */ - -# ifdef PNG_SAVE_UNKNOWN_CHUNKS_SUPPORTED - { - /* keep is currently just the per-chunk setting, if there was no - * setting change it to the global default now (not that this may - * still be AS_DEFAULT) then obtain the cache of the chunk if required, - * if not simply skip the chunk. - */ - if (keep == PNG_HANDLE_CHUNK_AS_DEFAULT) - keep = png_ptr->unknown_default; - - if (keep == PNG_HANDLE_CHUNK_ALWAYS || - (keep == PNG_HANDLE_CHUNK_IF_SAFE && - PNG_CHUNK_ANCILLARY(png_ptr->chunk_name))) - { - if (!png_cache_unknown_chunk(png_ptr, length)) - keep = PNG_HANDLE_CHUNK_NEVER; - } - - else - png_crc_finish(png_ptr, length); - } -# else -# ifndef PNG_READ_USER_CHUNKS_SUPPORTED -# error no method to support READ_UNKNOWN_CHUNKS -# endif - - { - /* If here there is no read callback pointer set and no support is - * compiled in to just save the unknown chunks, so simply skip this - * chunk. If 'keep' is something other than AS_DEFAULT or NEVER then - * the app has erroneously asked for unknown chunk saving when there - * is no support. - */ - if (keep > PNG_HANDLE_CHUNK_NEVER) - png_app_error(png_ptr, "no unknown chunk support available"); - - png_crc_finish(png_ptr, length); - } -# endif - -# ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED - /* Now store the chunk in the chunk list if appropriate, and if the limits - * permit it. - */ - if (keep == PNG_HANDLE_CHUNK_ALWAYS || - (keep == PNG_HANDLE_CHUNK_IF_SAFE && - PNG_CHUNK_ANCILLARY(png_ptr->chunk_name))) - { -# ifdef PNG_USER_LIMITS_SUPPORTED - switch (png_ptr->user_chunk_cache_max) - { - case 2: - png_ptr->user_chunk_cache_max = 1; - png_chunk_benign_error(png_ptr, "no space in chunk cache"); - /* FALL THROUGH */ - case 1: - /* NOTE: prior to 1.6.0 this case resulted in an unknown critical - * chunk being skipped, now there will be a hard error below. - */ - break; - - default: /* not at limit */ - --(png_ptr->user_chunk_cache_max); - /* FALL THROUGH */ - case 0: /* no limit */ -# endif /* PNG_USER_LIMITS_SUPPORTED */ - /* Here when the limit isn't reached or when limits are compiled - * out; store the chunk. - */ - png_set_unknown_chunks(png_ptr, info_ptr, - &png_ptr->unknown_chunk, 1); - handled = 1; -# ifdef PNG_USER_LIMITS_SUPPORTED - break; - } -# endif - } -# else /* no store support: the chunk must be handled by the user callback */ - PNG_UNUSED(info_ptr) -# endif - - /* Regardless of the error handling below the cached data (if any) can be - * freed now. Notice that the data is not freed if there is a png_error, but - * it will be freed by destroy_read_struct. - */ - if (png_ptr->unknown_chunk.data != NULL) - png_free(png_ptr, png_ptr->unknown_chunk.data); - png_ptr->unknown_chunk.data = NULL; - -#else /* !PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */ - /* There is no support to read an unknown chunk, so just skip it. */ - png_crc_finish(png_ptr, length); - PNG_UNUSED(info_ptr) - PNG_UNUSED(keep) -#endif /* !PNG_READ_UNKNOWN_CHUNKS_SUPPORTED */ - - /* Check for unhandled critical chunks */ - if (!handled && PNG_CHUNK_CRITICAL(png_ptr->chunk_name)) - png_chunk_error(png_ptr, "unhandled critical chunk"); -} - -/* 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_structrp 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_const_structrp 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 memcpy(). A memcpy() - * will also happen if interlacing isn't supported or if the application - * does not call png_set_interlace_handling(). In the latter cases the - * caller just gets a sequence of the unexpanded rows from each interlace - * pass. - */ -#ifdef PNG_READ_INTERLACING_SUPPORTED - if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE) && - pass < 6 && (display == 0 || - /* The following copies everything for 'display' on passes 0, 2 and 4. */ - (display == 1 && (pass & 1) != 0))) - { - /* Narrow images may have no bits in a pass; the caller should handle - * this, but this test is cheap: - */ - if (row_width <= PNG_PASS_START_COL(pass)) - return; - - if (pixel_depth < 8) - { - /* For pixel depths up to 4 bpp the 8-pixel mask can be expanded to fit - * into 32 bits, then a single loop over the bytes using the four byte - * values in the 32-bit mask can be used. For the 'display' option the - * expanded mask may also not require any masking within a byte. To - * make this work the PACKSWAP option must be taken into account - it - * simply requires the pixels to be reversed in each byte. - * - * The 'regular' case requires a mask for each of the first 6 passes, - * the 'display' case does a copy for the even passes in the range - * 0..6. This has already been handled in the test above. - * - * The masks are arranged as four bytes with the first byte to use in - * the lowest bits (little-endian) regardless of the order (PACKSWAP or - * not) of the pixels in each byte. - * - * NOTE: the whole of this logic depends on the caller of this function - * only calling it on rows appropriate to the pass. This function only - * understands the 'x' logic; the 'y' logic is handled by the caller. - * - * The following defines allow generation of compile time constant bit - * masks for each pixel depth and each possibility of swapped or not - * swapped bytes. Pass 'p' is in the range 0..6; 'x', a pixel index, - * is in the range 0..7; and the result is 1 if the pixel is to be - * copied in the pass, 0 if not. 'S' is for the sparkle method, 'B' - * for the block method. - * - * With some compilers a compile time expression of the general form: - * - * (shift >= 32) ? (a >> (shift-32)) : (b >> shift) - * - * Produces warnings with values of 'shift' in the range 33 to 63 - * because the right hand side of the ?: expression is evaluated by - * the compiler even though it isn't used. Microsoft Visual C (various - * versions) and the Intel C compiler are known to do this. To avoid - * this the following macros are used in 1.5.6. This is a temporary - * solution to avoid destabilizing the code during the release process. - */ -# if PNG_USE_COMPILE_TIME_MASKS -# define PNG_LSR(x,s) ((x)>>((s) & 0x1f)) -# define PNG_LSL(x,s) ((x)<<((s) & 0x1f)) -# else -# define PNG_LSR(x,s) ((x)>>(s)) -# define PNG_LSL(x,s) ((x)<<(s)) -# endif -# define S_COPY(p,x) (((p)<4 ? PNG_LSR(0x80088822,(3-(p))*8+(7-(x))) :\ - PNG_LSR(0xaa55ff00,(7-(p))*8+(7-(x)))) & 1) -# define B_COPY(p,x) (((p)<4 ? PNG_LSR(0xff0fff33,(3-(p))*8+(7-(x))) :\ - PNG_LSR(0xff55ff00,(7-(p))*8+(7-(x)))) & 1) - - /* Return a mask for pass 'p' pixel 'x' at depth 'd'. The mask is - * little endian - the first pixel is at bit 0 - however the extra - * parameter 's' can be set to cause the mask position to be swapped - * within each byte, to match the PNG format. This is done by XOR of - * the shift with 7, 6 or 4 for bit depths 1, 2 and 4. - */ -# define PIXEL_MASK(p,x,d,s) \ - (PNG_LSL(((PNG_LSL(1U,(d)))-1),(((x)*(d))^((s)?8-(d):0)))) - - /* Hence generate the appropriate 'block' or 'sparkle' pixel copy mask. - */ -# define S_MASKx(p,x,d,s) (S_COPY(p,x)?PIXEL_MASK(p,x,d,s):0) -# define B_MASKx(p,x,d,s) (B_COPY(p,x)?PIXEL_MASK(p,x,d,s):0) - - /* Combine 8 of these to get the full mask. For the 1-bpp and 2-bpp - * cases the result needs replicating, for the 4-bpp case the above - * generates a full 32 bits. - */ -# define MASK_EXPAND(m,d) ((m)*((d)==1?0x01010101:((d)==2?0x00010001:1))) - -# define S_MASK(p,d,s) MASK_EXPAND(S_MASKx(p,0,d,s) + S_MASKx(p,1,d,s) +\ - S_MASKx(p,2,d,s) + S_MASKx(p,3,d,s) + S_MASKx(p,4,d,s) +\ - S_MASKx(p,5,d,s) + S_MASKx(p,6,d,s) + S_MASKx(p,7,d,s), d) - -# define B_MASK(p,d,s) MASK_EXPAND(B_MASKx(p,0,d,s) + B_MASKx(p,1,d,s) +\ - B_MASKx(p,2,d,s) + B_MASKx(p,3,d,s) + B_MASKx(p,4,d,s) +\ - B_MASKx(p,5,d,s) + B_MASKx(p,6,d,s) + B_MASKx(p,7,d,s), d) - -#if PNG_USE_COMPILE_TIME_MASKS - /* Utility macros to construct all the masks for a depth/swap - * combination. The 's' parameter says whether the format is PNG - * (big endian bytes) or not. Only the three odd-numbered passes are - * required for the display/block algorithm. - */ -# define S_MASKS(d,s) { S_MASK(0,d,s), S_MASK(1,d,s), S_MASK(2,d,s),\ - S_MASK(3,d,s), S_MASK(4,d,s), S_MASK(5,d,s) } - -# define B_MASKS(d,s) { B_MASK(1,d,s), B_MASK(3,d,s), B_MASK(5,d,s) } - -# define DEPTH_INDEX(d) ((d)==1?0:((d)==2?1:2)) - - /* Hence the pre-compiled masks indexed by PACKSWAP (or not), depth and - * then pass: - */ - static PNG_CONST png_uint_32 row_mask[2/*PACKSWAP*/][3/*depth*/][6] = - { - /* Little-endian byte masks for PACKSWAP */ - { S_MASKS(1,0), S_MASKS(2,0), S_MASKS(4,0) }, - /* Normal (big-endian byte) masks - PNG format */ - { S_MASKS(1,1), S_MASKS(2,1), S_MASKS(4,1) } - }; - - /* display_mask has only three entries for the odd passes, so index by - * pass>>1. - */ - static PNG_CONST png_uint_32 display_mask[2][3][3] = - { - /* Little-endian byte masks for PACKSWAP */ - { B_MASKS(1,0), B_MASKS(2,0), B_MASKS(4,0) }, - /* Normal (big-endian byte) masks - PNG format */ - { B_MASKS(1,1), B_MASKS(2,1), B_MASKS(4,1) } - }; - -# define MASK(pass,depth,display,png)\ - ((display)?display_mask[png][DEPTH_INDEX(depth)][pass>>1]:\ - row_mask[png][DEPTH_INDEX(depth)][pass]) - -#else /* !PNG_USE_COMPILE_TIME_MASKS */ - /* This is the runtime alternative: it seems unlikely that this will - * ever be either smaller or faster than the compile time approach. - */ -# define MASK(pass,depth,display,png)\ - ((display)?B_MASK(pass,depth,png):S_MASK(pass,depth,png)) -#endif /* !PNG_USE_COMPILE_TIME_MASKS */ - - /* Use the appropriate mask to copy the required bits. In some cases - * the byte mask will be 0 or 0xff; optimize these cases. row_width is - * the number of pixels, but the code copies bytes, so it is necessary - * to special case the end. - */ - png_uint_32 pixels_per_byte = 8 / pixel_depth; - png_uint_32 mask; - -# ifdef PNG_READ_PACKSWAP_SUPPORTED - if (png_ptr->transformations & PNG_PACKSWAP) - mask = MASK(pass, pixel_depth, display, 0); - - else -# endif - mask = MASK(pass, pixel_depth, display, 1); - - for (;;) - { - png_uint_32 m; - - /* It doesn't matter in the following if png_uint_32 has more than - * 32 bits because the high bits always match those in m<<24; it is, - * however, essential to use OR here, not +, because of this. - */ - m = mask; - mask = (m >> 8) | (m << 24); /* rotate right to good compilers */ - m &= 0xff; - - if (m != 0) /* something to copy */ - { - if (m != 0xff) - *dp = (png_byte)((*dp & ~m) | (*sp & m)); - else - *dp = *sp; - } - - /* NOTE: this may overwrite the last byte with garbage if the image - * is not an exact number of bytes wide; libpng has always done - * this. - */ - if (row_width <= pixels_per_byte) - break; /* May need to restore part of the last byte */ - - row_width -= pixels_per_byte; - ++dp; - ++sp; - } - } - - else /* pixel_depth >= 8 */ - { - unsigned int bytes_to_copy, bytes_to_jump; - - /* Validate the depth - it must be a multiple of 8 */ - if (pixel_depth & 7) - png_error(png_ptr, "invalid user transform pixel depth"); - - pixel_depth >>= 3; /* now in bytes */ - row_width *= pixel_depth; - - /* Regardless of pass number the Adam 7 interlace always results in a - * fixed number of pixels to copy then to skip. There may be a - * different number of pixels to skip at the start though. - */ - { - unsigned int offset = PNG_PASS_START_COL(pass) * pixel_depth; - - row_width -= offset; - dp += offset; - sp += offset; - } - - /* Work out the bytes to copy. */ - if (display != 0) - { - /* When doing the 'block' algorithm the pixel in the pass gets - * replicated to adjacent pixels. This is why the even (0,2,4,6) - * passes are skipped above - the entire expanded row is copied. - */ - bytes_to_copy = (1<<((6-pass)>>1)) * pixel_depth; - - /* But don't allow this number to exceed the actual row width. */ - if (bytes_to_copy > row_width) - bytes_to_copy = 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 memcpy there. - */ - if (bytes_to_copy < 16 /*else use 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_aligncast(png_uint_32p,dp); - png_const_uint_32p sp32 = png_aligncastconst( - png_const_uint_32p, sp); - size_t skip = (bytes_to_jump-bytes_to_copy) / - (sizeof (png_uint_32)); - - do - { - size_t c = bytes_to_copy; - do - { - *dp32++ = *sp32++; - c -= (sizeof (png_uint_32)); - } - while (c > 0); - - if (row_width <= bytes_to_jump) - return; - - dp32 += skip; - sp32 += skip; - row_width -= bytes_to_jump; - } - while (bytes_to_copy <= row_width); - - /* Get to here when the row_width truncates the final copy. - * There will be 1-3 bytes left to copy, so don't try the - * 16-bit loop below. - */ - dp = (png_bytep)dp32; - sp = (png_const_bytep)sp32; - do - *dp++ = *sp++; - while (--row_width > 0); - return; - } - - /* Else do it in 16-bit quantities, but only if the size is - * not too large. - */ - else - { - png_uint_16p dp16 = png_aligncast(png_uint_16p, dp); - png_const_uint_16p sp16 = png_aligncastconst( - png_const_uint_16p, sp); - size_t skip = (bytes_to_jump-bytes_to_copy) / - (sizeof (png_uint_16)); - - do - { - size_t c = bytes_to_copy; - do - { - *dp16++ = *sp16++; - c -= (sizeof (png_uint_16)); - } - while (c > 0); - - if (row_width <= bytes_to_jump) - return; - - dp16 += skip; - sp16 += skip; - row_width -= bytes_to_jump; - } - while (bytes_to_copy <= row_width); - - /* End of row - 1 byte left, bytes_to_copy > row_width: */ - dp = (png_bytep)dp16; - sp = (png_const_bytep)sp16; - do - *dp++ = *sp++; - while (--row_width > 0); - return; - } - } -#endif /* PNG_ALIGN_ code */ - - /* The true default - use a memcpy: */ - for (;;) - { - 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 /* PNG_READ_INTERLACING_SUPPORTED */ - - /* If here then the switch above wasn't used so just 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.) - */ - 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++) - { - unsigned int tmp = *dp & (0x7f7f >> (7 - dshift)); - tmp |= v << dshift; - *dp = (png_byte)(tmp & 0xff); - - 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++) - { - unsigned int tmp = *dp & (0x3f3f >> (6 - dshift)); - tmp |= v << dshift; - *dp = (png_byte)(tmp & 0xff); - - 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++) - { - unsigned int tmp = *dp & (0xf0f >> (4 - dshift)); - tmp |= v << dshift; - *dp = (png_byte)(tmp & 0xff); - - if (dshift == s_end) - { - dshift = s_start; - dp--; - } - - else - dshift += s_inc; - } - - if (sshift == s_end) - { - sshift = s_start; - sp--; - } - - else - sshift += s_inc; - } - break; - } - - default: - { - png_size_t pixel_bytes = (row_info->pixel_depth >> 3); - - png_bytep sp = row + (png_size_t)(row_info->width - 1) - * pixel_bytes; - - png_bytep dp = row + (png_size_t)(final_width - 1) * pixel_bytes; - - int jstop = png_pass_inc[pass]; - png_uint_32 i; - - for (i = 0; i < row_info->width; i++) - { - png_byte v[8]; /* SAFE; pixel_depth does not exceed 64 */ - int j; - - memcpy(v, sp, pixel_bytes); - - for (j = 0; j < jstop; j++) - { - 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; - - a += *row; - *row++ = (png_byte)a; - } -} - -static void -png_init_filter_functions(png_structrp pp) - /* This function is called once for every PNG image (except for PNG images - * that only use PNG_FILTER_VALUE_NONE for all rows) to set the - * implementations required to reverse the filtering of PNG rows. Reversing - * the filter is the first transformation performed on the row data. It is - * performed in place, therefore an implementation can be selected based on - * the image pixel format. If the implementation depends on image width then - * take care to ensure that it works correctly if the image is interlaced - - * interlacing causes the actual row width to vary. - */ -{ - unsigned int bpp = (pp->pixel_depth + 7) >> 3; - - pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub; - pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up; - pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg; - if (bpp == 1) - pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = - png_read_filter_row_paeth_1byte_pixel; - else - pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = - png_read_filter_row_paeth_multibyte_pixel; - -#ifdef PNG_FILTER_OPTIMIZATIONS - /* To use this define PNG_FILTER_OPTIMIZATIONS as the name of a function to - * call to install hardware optimizations for the above functions; simply - * replace whatever elements of the pp->read_filter[] array with a hardware - * specific (or, for that matter, generic) optimization. - * - * To see an example of this examine what configure.ac does when - * --enable-arm-neon is specified on the command line. - */ - PNG_FILTER_OPTIMIZATIONS(pp, bpp); -#endif -} - -void /* PRIVATE */ -png_read_filter_row(png_structrp pp, png_row_infop row_info, png_bytep row, - png_const_bytep prev_row, int filter) -{ - /* OPTIMIZATION: DO NOT MODIFY THIS FUNCTION, instead #define - * PNG_FILTER_OPTIMIZATIONS to a function that overrides the generic - * implementations. See png_init_filter_functions above. - */ - if (filter > PNG_FILTER_VALUE_NONE && filter < PNG_FILTER_VALUE_LAST) - { - if (pp->read_filter[0] == NULL) - png_init_filter_functions(pp); - - pp->read_filter[filter-1](row_info, row, prev_row); - } -} - -#ifdef PNG_SEQUENTIAL_READ_SUPPORTED -void /* PRIVATE */ -png_read_IDAT_data(png_structrp png_ptr, png_bytep output, - png_alloc_size_t avail_out) -{ - /* Loop reading IDATs and decompressing the result into output[avail_out] */ - png_ptr->zstream.next_out = output; - png_ptr->zstream.avail_out = 0; /* safety: set below */ - - if (output == NULL) - avail_out = 0; - - do - { - int ret; - png_byte tmpbuf[PNG_INFLATE_BUF_SIZE]; - - if (png_ptr->zstream.avail_in == 0) - { - uInt avail_in; - png_bytep buffer; - - while (png_ptr->idat_size == 0) - { - png_crc_finish(png_ptr, 0); - - png_ptr->idat_size = png_read_chunk_header(png_ptr); - /* This is an error even in the 'check' case because the code just - * consumed a non-IDAT header. - */ - if (png_ptr->chunk_name != png_IDAT) - png_error(png_ptr, "Not enough image data"); - } - - avail_in = png_ptr->IDAT_read_size; - - if (avail_in > png_ptr->idat_size) - avail_in = (uInt)png_ptr->idat_size; - - /* A PNG with a gradually increasing IDAT size will defeat this attempt - * to minimize memory usage by causing lots of re-allocs, but - * realistically doing IDAT_read_size re-allocs is not likely to be a - * big problem. - */ - buffer = png_read_buffer(png_ptr, avail_in, 0/*error*/); - - png_crc_read(png_ptr, buffer, avail_in); - png_ptr->idat_size -= avail_in; - - png_ptr->zstream.next_in = buffer; - png_ptr->zstream.avail_in = avail_in; - } - - /* And set up the output side. */ - if (output != NULL) /* standard read */ - { - uInt out = ZLIB_IO_MAX; - - if (out > avail_out) - out = (uInt)avail_out; - - avail_out -= out; - png_ptr->zstream.avail_out = out; - } - - else /* after last row, checking for end */ - { - png_ptr->zstream.next_out = tmpbuf; - png_ptr->zstream.avail_out = (sizeof tmpbuf); - } - - /* Use NO_FLUSH; this gives zlib the maximum opportunity to optimize the - * process. If the LZ stream is truncated the sequential reader will - * terminally damage the stream, above, by reading the chunk header of the - * following chunk (it then exits with png_error). - * - * TODO: deal more elegantly with truncated IDAT lists. - */ - ret = inflate(&png_ptr->zstream, Z_NO_FLUSH); - - /* Take the unconsumed output back. */ - if (output != NULL) - avail_out += png_ptr->zstream.avail_out; - - else /* avail_out counts the extra bytes */ - avail_out += (sizeof tmpbuf) - png_ptr->zstream.avail_out; - - png_ptr->zstream.avail_out = 0; - - if (ret == Z_STREAM_END) - { - /* Do this for safety; we won't read any more into this row. */ - png_ptr->zstream.next_out = NULL; - - png_ptr->mode |= PNG_AFTER_IDAT; - png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED; - - if (png_ptr->zstream.avail_in > 0 || png_ptr->idat_size > 0) - png_chunk_benign_error(png_ptr, "Extra compressed data"); - break; - } - - if (ret != Z_OK) - { - png_zstream_error(png_ptr, ret); - - if (output != NULL) - png_chunk_error(png_ptr, png_ptr->zstream.msg); - - else /* checking */ - { - png_chunk_benign_error(png_ptr, png_ptr->zstream.msg); - return; - } - } - } while (avail_out > 0); - - if (avail_out > 0) - { - /* The stream ended before the image; this is the same as too few IDATs so - * should be handled the same way. - */ - if (output != NULL) - png_error(png_ptr, "Not enough image data"); - - else /* the deflate stream contained extra data */ - png_chunk_benign_error(png_ptr, "Too much image data"); - } -} - -void /* PRIVATE */ -png_read_finish_IDAT(png_structrp png_ptr) -{ - /* We don't need any more data and the stream should have ended, however the - * LZ end code may actually not have been processed. In this case we must - * read it otherwise stray unread IDAT data or, more likely, an IDAT chunk - * may still remain to be consumed. - */ - if (!(png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED)) - { - /* The NULL causes png_read_IDAT_data to swallow any remaining bytes in - * the compressed stream, but the stream may be damaged too, so even after - * this call we may need to terminate the zstream ownership. - */ - png_read_IDAT_data(png_ptr, NULL, 0); - png_ptr->zstream.next_out = NULL; /* safety */ - - /* Now clear everything out for safety; the following may not have been - * done. - */ - if (!(png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED)) - { - png_ptr->mode |= PNG_AFTER_IDAT; - png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED; - } - } - - /* If the zstream has not been released do it now *and* terminate the reading - * of the final IDAT chunk. - */ - if (png_ptr->zowner == png_IDAT) - { - /* Always do this; the pointers otherwise point into the read buffer. */ - png_ptr->zstream.next_in = NULL; - png_ptr->zstream.avail_in = 0; - - /* Now we no longer own the zstream. */ - png_ptr->zowner = 0; - - /* The slightly weird semantics of the sequential IDAT reading is that we - * are always in or at the end of an IDAT chunk, so we always need to do a - * crc_finish here. If idat_size is non-zero we also need to read the - * spurious bytes at the end of the chunk now. - */ - (void)png_crc_finish(png_ptr, png_ptr->idat_size); - } -} - -void /* PRIVATE */ -png_read_finish_row(png_structrp png_ptr) -{ - /* 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}; - - png_debug(1, "in png_read_finish_row"); - png_ptr->row_number++; - if (png_ptr->row_number < png_ptr->num_rows) - return; - - 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. - */ - 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; - } - - /* Here after at the end of the last row of the last pass. */ - png_read_finish_IDAT(png_ptr); -} -#endif /* PNG_SEQUENTIAL_READ_SUPPORTED */ - -void /* PRIVATE */ -png_read_start_row(png_structrp png_ptr) -{ - /* 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}; - - int max_pixel_depth; - png_size_t row_bytes; - - png_debug(1, "in png_read_start_row"); - -#ifdef PNG_READ_TRANSFORMS_SUPPORTED - png_init_read_transformations(png_ptr); -#endif - 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 - { - 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"); - - 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); - - /* The sequential reader needs a buffer for IDAT, but the progressive reader - * does not, so free the read buffer now regardless; the sequential reader - * reallocates it on demand. - */ - if (png_ptr->read_buffer) - { - png_bytep buffer = png_ptr->read_buffer; - - png_ptr->read_buffer_size = 0; - png_ptr->read_buffer = NULL; - png_free(png_ptr, buffer); - } - - /* Finally claim the zstream for the inflate of the IDAT data, use the bits - * value from the stream (note that this will result in a fatal error if the - * IDAT stream has a bogus deflate header window_bits value, but this should - * not be happening any longer!) - */ - if (png_inflate_claim(png_ptr, png_IDAT) != Z_OK) - png_error(png_ptr, png_ptr->zstream.msg); - - png_ptr->flags |= PNG_FLAG_ROW_INIT; -} -#endif /* PNG_READ_SUPPORTED */ |