diff options
author | Matt Johnston <matt@ucc.asn.au> | 2007-01-11 04:29:08 +0000 |
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committer | Matt Johnston <matt@ucc.asn.au> | 2007-01-11 04:29:08 +0000 |
commit | 943636c3e13f50bc0e29c5f69974541a296a3be2 (patch) | |
tree | 02a55d7bff75c51e641a556ad331460a1d1270b6 /libtommath/bn_mp_count_bits.c | |
parent | 0a60ef26bd13e6007c4fdd0f09b5a8d4785113c0 (diff) | |
parent | 9d5ed350a749368c84254c11e7616ce3c891193a (diff) |
propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head c1db4398d56c56c6d06ae1e20c1e0d04dbb598ed)
to branch 'au.asn.ucc.matt.dropbear' (head d26d5eb2837f46b56a33fb0e7573aa0201abd4d5)
--HG--
extra : convert_revision : 7a0ae6de81402591a789486070007238169fafca
Diffstat (limited to 'libtommath/bn_mp_count_bits.c')
-rw-r--r-- | libtommath/bn_mp_count_bits.c | 45 |
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 $ */ |