X-Git-Url: https://pd.if.org/git/?a=blobdiff_plain;f=libtomcrypt%2Fsrc%2Fencauth%2Focb%2Focb_ntz.c;fp=libtomcrypt%2Fsrc%2Fencauth%2Focb%2Focb_ntz.c;h=cfdc667024e82786769440d5da28d252d99ad4b8;hb=66bc25938679f1d6a1d1200f329093d82a5e99b4;hp=0000000000000000000000000000000000000000;hpb=a52ee0733f420ca20224049260d6fc5cf7d8f621;p=zpackage

diff --git a/libtomcrypt/src/encauth/ocb/ocb_ntz.c b/libtomcrypt/src/encauth/ocb/ocb_ntz.c
new file mode 100644
index 0000000..cfdc667
--- /dev/null
+++ b/libtomcrypt/src/encauth/ocb/ocb_ntz.c
@@ -0,0 +1,40 @@
+/* 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.
+ */
+
+/**
+   @file ocb_ntz.c
+   OCB implementation, internal function, by Tom St Denis
+*/
+
+#include "tomcrypt.h"
+
+#ifdef LTC_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
+
+/* ref:         $Format:%D$ */
+/* git commit:  $Format:%H$ */
+/* commit time: $Format:%ai$ */