1 /* $NetBSD: crc.c,v 1.1.1.1 2008/12/22 00:18:12 haad Exp $ */ 2 3 /* 4 * Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved. 5 * Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved. 6 * 7 * This file is part of LVM2. 8 * 9 * This copyrighted material is made available to anyone wishing to use, 10 * modify, copy, or redistribute it subject to the terms and conditions 11 * of the GNU Lesser General Public License v.2.1. 12 * 13 * You should have received a copy of the GNU Lesser General Public License 14 * along with this program; if not, write to the Free Software Foundation, 15 * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 16 */ 17 18 #include "lib.h" 19 20 #include "crc.h" 21 22 /* Calculate an endian-independent CRC of supplied buffer */ 23 uint32_t calc_crc(uint32_t initial, const void *buf, uint32_t size) 24 { 25 static const uint32_t crctab[] = { 26 0x00000000, 0x1db71064, 0x3b6e20c8, 0x26d930ac, 27 0x76dc4190, 0x6b6b51f4, 0x4db26158, 0x5005713c, 28 0xedb88320, 0xf00f9344, 0xd6d6a3e8, 0xcb61b38c, 29 0x9b64c2b0, 0x86d3d2d4, 0xa00ae278, 0xbdbdf21c 30 }; 31 uint32_t i, crc = initial; 32 const uint8_t *data = (const uint8_t *) buf; 33 34 for (i = 0; i < size; i++) { 35 crc ^= *data++; 36 crc = (crc >> 4) ^ crctab[crc & 0xf]; 37 crc = (crc >> 4) ^ crctab[crc & 0xf]; 38 } 39 return crc; 40 } 41