Mercurial > dropbear
diff libtomcrypt/src/encauth/ocb/ocb_ntz.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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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/libtomcrypt/src/encauth/ocb/ocb_ntz.c Wed Mar 08 13:23:58 2006 +0000 @@ -0,0 +1,42 @@ +/* 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 + */ + +/** + @file ocb_ntz.c + OCB implementation, internal function, by Tom St Denis +*/ + +#include "tomcrypt.h" + +#ifdef OCB_MODE + +/** + Returns the number of leading zero bits [from lsb up] + @param x The 32-bit value to observe + @return The number of bits [from the lsb up] that are zero +*/ +int ocb_ntz(unsigned long x) +{ + int c; + x &= 0xFFFFFFFFUL; + c = 0; + while ((x & 1) == 0) { + ++c; + x >>= 1; + } + return c; +} + +#endif + +/* $Source: /cvs/libtom/libtomcrypt/src/encauth/ocb/ocb_ntz.c,v $ */ +/* $Revision: 1.3 $ */ +/* $Date: 2005/05/05 14:35:58 $ */