chromium/third_party/flac/src/libFLAC/crc.c

/* libFLAC - Free Lossless Audio Codec library
 * Copyright (C) 2000-2009  Josh Coalson
 * Copyright (C) 2011-2022  Xiph.Org Foundation
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 *
 * - Neither the name of the Xiph.org Foundation nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifdef HAVE_CONFIG_H
#  include <config.h>
#endif

#include "private/crc.h"

/* CRC-8, poly = x^8 + x^2 + x^1 + x^0, init = 0 */

FLAC__uint8 const FLAC__crc8_table[256] = …;

/* CRC-16, poly = x^16 + x^15 + x^2 + x^0, init = 0 */

FLAC__uint16 const FLAC__crc16_table[8][256] = …;

#if 0
void FLAC__crc16_init_table(void)
{
	int i, j;
	FLAC__uint16 polynomial, crc;
	polynomial = 0x8005;

	for(i = 0; i <= 0xFF; i++){
		crc = i << 8;

		for(j = 0; j < 8; j++)
			crc = (crc << 1) ^ (crc & (1 << 15) ? polynomial : 0);

		FLAC__crc16_table[0][i] = crc;
	}

	for(i = 0; i <= 0xFF; i++)
		for(j = 1; j < 8; j++)
			FLAC__crc16_table[j][i] = FLAC__crc16_table[0][FLAC__crc16_table[j - 1][i] >> 8] ^ (FLAC__crc16_table[j - 1][i] << 8);
}
#endif

FLAC__uint8 FLAC__crc8(const FLAC__byte *data, uint32_t len)
{ … }

FLAC__uint16 FLAC__crc16(const FLAC__byte *data, uint32_t len)
{ … }

FLAC__uint16 FLAC__crc16_update_words32(const FLAC__uint32 *words, uint32_t len, FLAC__uint16 crc)
{ … }

FLAC__uint16 FLAC__crc16_update_words64(const FLAC__uint64 *words, uint32_t len, FLAC__uint16 crc)
{ … }