src/libFLAC/crc.c

/* libFLAC - Free Lossless Audio Codec library
 * Copyright (C) 2000,2001  Josh Coalson
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA  02111-1307, USA.
 */

#include "private/crc.h"

byte FLAC__crc8(const byte *data, const unsigned len)
{
	static byte const crc8_table_[256] = {
		0x00, 0x07, 0x0E, 0x09, 0x1C, 0x1B, 0x12, 0x15,
		0x38, 0x3F, 0x36, 0x31, 0x24, 0x23, 0x2A, 0x2D,
		0x70, 0x77, 0x7E, 0x79, 0x6C, 0x6B, 0x62, 0x65,
		0x48, 0x4F, 0x46, 0x41, 0x54, 0x53, 0x5A, 0x5D,
		0xE0, 0xE7, 0xEE, 0xE9, 0xFC, 0xFB, 0xF2, 0xF5,
		0xD8, 0xDF, 0xD6, 0xD1, 0xC4, 0xC3, 0xCA, 0xCD,
		0x90, 0x97, 0x9E, 0x99, 0x8C, 0x8B, 0x82, 0x85,
		0xA8, 0xAF, 0xA6, 0xA1, 0xB4, 0xB3, 0xBA, 0xBD,
		0xC7, 0xC0, 0xC9, 0xCE, 0xDB, 0xDC, 0xD5, 0xD2,
		0xFF, 0xF8, 0xF1, 0xF6, 0xE3, 0xE4, 0xED, 0xEA,
		0xB7, 0xB0, 0xB9, 0xBE, 0xAB, 0xAC, 0xA5, 0xA2,
		0x8F, 0x88, 0x81, 0x86, 0x93, 0x94, 0x9D, 0x9A,
		0x27, 0x20, 0x29, 0x2E, 0x3B, 0x3C, 0x35, 0x32,
		0x1F, 0x18, 0x11, 0x16, 0x03, 0x04, 0x0D, 0x0A,
		0x57, 0x50, 0x59, 0x5E, 0x4B, 0x4C, 0x45, 0x42,
		0x6F, 0x68, 0x61, 0x66, 0x73, 0x74, 0x7D, 0x7A,
		0x89, 0x8E, 0x87, 0x80, 0x95, 0x92, 0x9B, 0x9C,
		0xB1, 0xB6, 0xBF, 0xB8, 0xAD, 0xAA, 0xA3, 0xA4,
		0xF9, 0xFE, 0xF7, 0xF0, 0xE5, 0xE2, 0xEB, 0xEC,
		0xC1, 0xC6, 0xCF, 0xC8, 0xDD, 0xDA, 0xD3, 0xD4,
		0x69, 0x6E, 0x67, 0x60, 0x75, 0x72, 0x7B, 0x7C,
		0x51, 0x56, 0x5F, 0x58, 0x4D, 0x4A, 0x43, 0x44,
		0x19, 0x1E, 0x17, 0x10, 0x05, 0x02, 0x0B, 0x0C,
		0x21, 0x26, 0x2F, 0x28, 0x3D, 0x3A, 0x33, 0x34,
		0x4E, 0x49, 0x40, 0x47, 0x52, 0x55, 0x5C, 0x5B,
		0x76, 0x71, 0x78, 0x7F, 0x6A, 0x6D, 0x64, 0x63,
		0x3E, 0x39, 0x30, 0x37, 0x22, 0x25, 0x2C, 0x2B,
		0x06, 0x01, 0x08, 0x0F, 0x1A, 0x1D, 0x14, 0x13,
		0xAE, 0xA9, 0xA0, 0xA7, 0xB2, 0xB5, 0xBC, 0xBB,
		0x96, 0x91, 0x98, 0x9F, 0x8A, 0x8D, 0x84, 0x83,
		0xDE, 0xD9, 0xD0, 0xD7, 0xC2, 0xC5, 0xCC, 0xCB,
		0xE6, 0xE1, 0xE8, 0xEF, 0xFA, 0xFD, 0xF4, 0xF3
	};
	unsigned i;
	byte crc = 0;

	for(i = 0; i < len; i++)
		crc = crc8_table_[crc ^ *data++];

	return crc;
}