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 */
23uint32_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