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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 der_decode_short_integer.c
ASN.1 DER, decode an integer, Tom St Denis
*/
#ifdef LTC_DER
/**
Read a short integer
@param in The DER encoded data
@param inlen Size of data
@param num [out] The integer to decode
@return CRYPT_OK if successful
*/
int der_decode_short_integer(const unsigned char *in, unsigned long inlen, unsigned long *num)
{
unsigned long len, x, y;
LTC_ARGCHK(num != NULL);
LTC_ARGCHK(in != NULL);
/* check length */
if (inlen < 2) {
return CRYPT_INVALID_PACKET;
}
/* check header */
x = 0;
if ((in[x++] & 0x1F) != 0x02) {
return CRYPT_INVALID_PACKET;
}
/* get the packet len */
len = in[x++];
if (x + len > inlen) {
return CRYPT_INVALID_PACKET;
}
/* read number */
y = 0;
while (len--) {
y = (y<<8) | (unsigned long)in[x++];
}
*num = y;
return CRYPT_OK;
}
#endif
/* $Source: /cvs/libtom/libtomcrypt/src/pk/asn1/der/short_integer/der_decode_short_integer.c,v $ */
/* $Revision: 1.7 $ */
/* $Date: 2006/12/28 01:27:24 $ */
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