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Diffstat (limited to 'libtomcrypt/src/encauth/ocb/ocb_ntz.c')
| -rw-r--r-- | libtomcrypt/src/encauth/ocb/ocb_ntz.c | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/libtomcrypt/src/encauth/ocb/ocb_ntz.c b/libtomcrypt/src/encauth/ocb/ocb_ntz.c new file mode 100644 index 0000000..9b83c53 --- /dev/null +++ b/libtomcrypt/src/encauth/ocb/ocb_ntz.c @@ -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, tomstdenis@gmail.com, 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 $ */ |