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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 /libtommath/bn_mp_count_bits.c
parent056b92bd4c8a42ce1843493310d382159166edb8 (diff)
parentc5fd7dd5548f28e32d846e39d17e5c4de4e769af (diff)
merge of '5fdf69ca60d1683cdd9f4c2595134bed26394834'
and '6b61c50f4cf888bea302ac8fcf5dbb573b443251' --HG-- extra : convert_revision : b1dd3b94e60a07a176dba2b035ac79968595990a
Diffstat (limited to 'libtommath/bn_mp_count_bits.c')
-rw-r--r--libtommath/bn_mp_count_bits.c45
1 files changed, 45 insertions, 0 deletions
diff --git a/libtommath/bn_mp_count_bits.c b/libtommath/bn_mp_count_bits.c
new file mode 100644
index 0000000..ff4db22
--- /dev/null
+++ b/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://math.libtomcrypt.com
+ */
+
+/* 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: 1.3 $ */
+/* $Date: 2006/03/31 14:18:44 $ */