crc.h (2602B)
1 /* libFLAC - Free Lossless Audio Codec library 2 * Copyright (C) 2000-2009 Josh Coalson 3 * Copyright (C) 2011-2018 Xiph.Org Foundation 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 9 * - Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 12 * - Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * - Neither the name of the Xiph.org Foundation nor the names of its 17 * contributors may be used to endorse or promote products derived from 18 * this software without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 23 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR 24 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 25 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 26 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 27 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 28 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 29 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 30 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 31 */ 32 33 #ifndef FLAC__PRIVATE__CRC_H 34 #define FLAC__PRIVATE__CRC_H 35 36 #include "../FLAC/ordinals.h" 37 38 /* 8 bit CRC generator, MSB shifted first 39 ** polynomial = x^8 + x^2 + x^1 + x^0 40 ** init = 0 41 */ 42 FLAC__uint8 FLAC__crc8(const FLAC__byte *data, uint32_t len); 43 44 /* 16 bit CRC generator, MSB shifted first 45 ** polynomial = x^16 + x^15 + x^2 + x^0 46 ** init = 0 47 */ 48 extern FLAC__uint16 const FLAC__crc16_table[8][256]; 49 50 #define FLAC__CRC16_UPDATE(data, crc) ((((crc)<<8) & 0xffff) ^ FLAC__crc16_table[0][((crc)>>8) ^ (data)]) 51 /* this alternate may be faster on some systems/compilers */ 52 #if 0 53 #define FLAC__CRC16_UPDATE(data, crc) ((((crc)<<8) ^ FLAC__crc16_table[0][((crc)>>8) ^ (data)]) & 0xffff) 54 #endif 55 56 FLAC__uint16 FLAC__crc16(const FLAC__byte *data, uint32_t len); 57 FLAC__uint16 FLAC__crc16_update_words32(const FLAC__uint32 *words, uint32_t len, FLAC__uint16 crc); 58 FLAC__uint16 FLAC__crc16_update_words64(const FLAC__uint64 *words, uint32_t len, FLAC__uint16 crc); 59 60 #endif