1/*
2 * cc_cmp_safe.c
3 * corecrypto
4 *
5 * Created on 04/22/2014
6 *
7 * Copyright (c) 2014,2015 Apple Inc. All rights reserved.
8 *
9 *
10 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
11 *
12 * This file contains Original Code and/or Modifications of Original Code
13 * as defined in and that are subject to the Apple Public Source License
14 * Version 2.0 (the 'License'). You may not use this file except in
15 * compliance with the License. The rights granted to you under the License
16 * may not be used to create, or enable the creation or redistribution of,
17 * unlawful or unlicensed copies of an Apple operating system, or to
18 * circumvent, violate, or enable the circumvention or violation of, any
19 * terms of an Apple operating system software license agreement.
20 *
21 * Please obtain a copy of the License at
22 * http://www.opensource.apple.com/apsl/ and read it before using this file.
23 *
24 * The Original Code and all software distributed under the License are
25 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
26 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
27 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
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29 * Please see the License for the specific language governing rights and
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31 *
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33 */
34
35#include <corecrypto/cc_priv.h>
36
37int cc_cmp_safe (size_t num, const void * ptr1, const void * ptr2)
38{
39 size_t i;
40 const uint8_t *s=(const uint8_t *)ptr1;
41 const uint8_t *t=(const uint8_t *)ptr2;
42 uint8_t flag=((num<=0)?1:0); // If 0 return an error
43 for (i=0;i<num;i++)
44 {
45 flag|=(s[i]^t[i]);
46 }
47 HEAVISIDE_STEP_UINT8(flag,flag); // flag=(flag==0)?0:1;
48 return flag; // 0 iff all bytes were equal, 1 if there is any difference
49}
50