1/* 2 * Copyright (c) 2001-2007 Apple Inc. All Rights Reserved. 3 * 4 * @APPLE_LICENSE_HEADER_START@ 5 * 6 * This file contains Original Code and/or Modifications of Original Code 7 * as defined in and that are subject to the Apple Public Source License 8 * Version 2.0 (the 'License'). You may not use this file except in 9 * compliance with the License. Please obtain a copy of the License at 10 * http://www.opensource.apple.com/apsl/ and read it before using this 11 * file. 12 * 13 * The Original Code and all software distributed under the License are 14 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 15 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 16 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 17 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 18 * Please see the License for the specific language governing rights and 19 * limitations under the License. 20 * 21 * @APPLE_LICENSE_HEADER_END@ 22 */ 23/* 24 * BLBlockChecksum.c 25 * bless 26 * 27 * Created by Shantonu Sen <ssen@apple.com> on Wed Feb 28 2002. 28 * Copyright (c) 2002-2007 Apple Inc. All Rights Reserved. 29 * 30 * $Id: BLBlockChecksum.c,v 1.8 2006/02/20 22:49:56 ssen Exp $ 31 * 32 */ 33 34#include <sys/types.h> 35 36#include "bless_private.h" 37 38/* 39 * Taken from MediaKit. Used to checksum secondary loader 40 * presently 41 */ 42 43uint32_t BLBlockChecksum(const void *buf,uint32_t length) 44{ 45 uint32_t sum = 0; 46 uint32_t *s = (uint32_t *) buf; 47 uint32_t *t = s + length/4; 48 49 while (s < t) { 50 // rotate 1 bit left and add bytes 51 sum = ((sum >> 31) | (sum << 1)) + *s++; 52 } 53 return sum; 54} 55 56