/*      $NetBSD: crc.c,v 1.1.1.1 2008/12/22 00:18:12 haad Exp $ */

/*
* Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
* Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
*
* This file is part of LVM2.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU Lesser General Public License v.2.1.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#include "lib.h"

#include "crc.h"

/* Calculate an endian-independent CRC of supplied buffer */
uint32_t calc_crc(uint32_t initial, const void *buf, uint32_t size)
{
       static const uint32_t crctab[] = {
               0x00000000, 0x1db71064, 0x3b6e20c8, 0x26d930ac,
               0x76dc4190, 0x6b6b51f4, 0x4db26158, 0x5005713c,
               0xedb88320, 0xf00f9344, 0xd6d6a3e8, 0xcb61b38c,
               0x9b64c2b0, 0x86d3d2d4, 0xa00ae278, 0xbdbdf21c
       };
       uint32_t i, crc = initial;
       const uint8_t *data = (const uint8_t *) buf;

       for (i = 0; i < size; i++) {
               crc ^= *data++;
               crc = (crc >> 4) ^ crctab[crc & 0xf];
               crc = (crc >> 4) ^ crctab[crc & 0xf];
       }
       return crc;
}