ltm-0.41

lib/hcrypto/libtommath/bn_mp_count_bits.c

@@ -0,0 +1,45 @@
+#include <tommath.h>
+#ifdef BN_MP_COUNT_BITS_C
+/* LibTomMath, multiple-precision integer library -- Tom St Denis
+ *
+ * LibTomMath is a library that provides multiple-precision
+ * integer arithmetic as well as number theoretic functionality.
+ *
+ * The library was designed directly after the MPI library by
+ * Michael Fromberger but has been written from scratch with
+ * additional optimizations in place.
+ *
+ * The library is free for all purposes without any express
+ * guarantee it works.
+ *
+ * Tom St Denis, tomstdenis@gmail.com, http://libtom.org
+ */
+
+/* returns the number of bits in an int */
+int
+mp_count_bits (mp_int * a)
+{
+  int     r;
+  mp_digit q;
+
+  /* shortcut */
+  if (a->used == 0) {
+    return 0;
+  }
+
+  /* get number of digits and add that */
+  r = (a->used - 1) * DIGIT_BIT;
+  
+  /* take the last digit and count the bits in it */
+  q = a->dp[a->used - 1];
+  while (q > ((mp_digit) 0)) {
+    ++r;
+    q >>= ((mp_digit) 1);
+  }
+  return r;
+}
+#endif
+
+/* $Source: /cvs/libtom/libtommath/bn_mp_count_bits.c,v $ */
+/* $Revision: 1.4 $ */
+/* $Date: 2006/12/28 01:25:13 $ */