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authorMatt Johnston <matt@ucc.asn.au>2007-02-03 08:20:34 +0000
committerMatt Johnston <matt@ucc.asn.au>2007-02-03 08:20:34 +0000
commitd9aeb2773e236e662c8b493f4bcee978f9908d7c (patch)
treebac48e388bf3ac739ae14cdf98da0eb4bb9d17bf /libtomcrypt/src/encauth/ocb/ocb_ntz.c
parent056b92bd4c8a42ce1843493310d382159166edb8 (diff)
parentc5fd7dd5548f28e32d846e39d17e5c4de4e769af (diff)
merge of '5fdf69ca60d1683cdd9f4c2595134bed26394834'
and '6b61c50f4cf888bea302ac8fcf5dbb573b443251' --HG-- extra : convert_revision : b1dd3b94e60a07a176dba2b035ac79968595990a
Diffstat (limited to 'libtomcrypt/src/encauth/ocb/ocb_ntz.c')
-rw-r--r--libtomcrypt/src/encauth/ocb/ocb_ntz.c42
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..8100ec0
--- /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.com
+ */
+
+/**
+ @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: 1.4 $ */
+/* $Date: 2006/03/31 14:15:35 $ */