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/*
* Copyright (c) 2001-2007, Tom St Denis
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/* LibTomCrypt, modular cryptographic library -- Tom St Denis
*
* LibTomCrypt is a library that provides various cryptographic
* algorithms in a highly modular and flexible manner.
*
* The library is free for all purposes without any express
* guarantee it works.
*
* Tom St Denis, tomstdenis@gmail.com, http://libtom.org
*/
#include "tomcrypt.h"
/**
@file mem_neq.c
Compare two blocks of memory for inequality.
Steffen Jaeckel
*/
/**
Compare two blocks of memory for inequality.
The usage is similar to that of standard memcmp(), but you can only test
if the memory is equal or not - you can not determine by how much the
first different byte differs.
@param a The first memory region
@param b The second memory region
@param len The length of the area to compare (octets)
@return 0 when a and b are equal for len bytes, else they are not equal.
*/
int mem_neq(const void *a, const void *b, size_t len)
{
unsigned char ret = 0;
const unsigned char* pa;
const unsigned char* pb;
LTC_ARGCHK(a != NULL);
LTC_ARGCHK(b != NULL);
pa = a;
pb = b;
while (len-- > 0) {
ret |= *pa ^ *pb;
++pa;
++pb;
}
ret |= ret >> 4;
ret |= ret >> 2;
ret |= ret >> 1;
ret &= 1;
return ret;
}
/* $Source$ */
/* $Revision$ */
/* $Date$ */
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