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 $ */