Mercurial > dropbear
view libtomcrypt/src/pk/asn1/der/short_integer/der_decode_short_integer.c @ 285:1b9e69c058d2
propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3)
to branch 'au.asn.ucc.matt.dropbear' (head fdf4a7a3b97ae5046139915de7e40399cceb2c01)
author | Matt Johnston <matt@ucc.asn.au> |
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date | Wed, 08 Mar 2006 13:23:58 +0000 |
parents | |
children | 0cbe8f6dbf9e |
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/* 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, [email protected], http://libtomcrypt.org */ #include "tomcrypt.h" /** @file der_decode_short_integer.c ASN.1 DER, decode an integer, Tom St Denis */ #ifdef LTC_DER /** Read a mp_int 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: 1.4 $ */ /* $Date: 2005/05/23 01:04:13 $ */