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      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