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1 /* Copyright (c) 2013 The Chromium OS Authors. All rights reserved.
2  * Use of this source code is governed by a BSD-style license that can be
3  * found in the LICENSE file.
4  *
5  * Utility functions that need to be built as part of the firmware.
6  */
7 
8 #include "sysincludes.h"
9 
10 #include "utility.h"
11 
SafeMemcmp(const void * s1,const void * s2,size_t n)12 int SafeMemcmp(const void *s1, const void *s2, size_t n) {
13 	const unsigned char *us1 = s1;
14 	const unsigned char *us2 = s2;
15 	int result = 0;
16 
17 	if (0 == n)
18 		return 0;
19 
20 	/*
21 	 * Code snippet without data-dependent branch due to Nate Lawson
22 	 * (nate@root.org) of Root Labs.
23 	 */
24 	while (n--)
25 		result |= *us1++ ^ *us2++;
26 
27 	return result != 0;
28 }
29