diff options
author | Matt Johnston <matt@ucc.asn.au> | 2007-01-11 03:14:55 +0000 |
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committer | Matt Johnston <matt@ucc.asn.au> | 2007-01-11 03:14:55 +0000 |
commit | 9d5ed350a749368c84254c11e7616ce3c891193a (patch) | |
tree | 6dacbff2e9f5c60a1568382db55c72dd6d2ce925 /libtommath/bn_mp_radix_size.c | |
parent | ca52f070aecf91e75f6ae6c87d4ae1a2189ccb14 (diff) | |
parent | 5ea605d8de5b4438deb4fa86c5231710dd09f934 (diff) |
propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 2af95f00ebd5bb7a28b3817db1218442c935388e)
to branch 'au.asn.ucc.matt.dropbear' (head ecd779509ef23a8cdf64888904fc9b31d78aa933)
--HG--
extra : convert_revision : d26d5eb2837f46b56a33fb0e7573aa0201abd4d5
Diffstat (limited to 'libtommath/bn_mp_radix_size.c')
-rw-r--r-- | libtommath/bn_mp_radix_size.c | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/libtommath/bn_mp_radix_size.c b/libtommath/bn_mp_radix_size.c new file mode 100644 index 0000000..c9e8822 --- /dev/null +++ b/libtommath/bn_mp_radix_size.c @@ -0,0 +1,78 @@ +#include <tommath.h> +#ifdef BN_MP_RADIX_SIZE_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 size of ASCII reprensentation */ +int mp_radix_size (mp_int * a, int radix, int *size) +{ + int res, digs; + mp_int t; + mp_digit d; + + *size = 0; + + /* special case for binary */ + if (radix == 2) { + *size = mp_count_bits (a) + (a->sign == MP_NEG ? 1 : 0) + 1; + return MP_OKAY; + } + + /* make sure the radix is in range */ + if (radix < 2 || radix > 64) { + return MP_VAL; + } + + if (mp_iszero(a) == MP_YES) { + *size = 2; + return MP_OKAY; + } + + /* digs is the digit count */ + digs = 0; + + /* if it's negative add one for the sign */ + if (a->sign == MP_NEG) { + ++digs; + } + + /* init a copy of the input */ + if ((res = mp_init_copy (&t, a)) != MP_OKAY) { + return res; + } + + /* force temp to positive */ + t.sign = MP_ZPOS; + + /* fetch out all of the digits */ + while (mp_iszero (&t) == MP_NO) { + if ((res = mp_div_d (&t, (mp_digit) radix, &t, &d)) != MP_OKAY) { + mp_clear (&t); + return res; + } + ++digs; + } + mp_clear (&t); + + /* return digs + 1, the 1 is for the NULL byte that would be required. */ + *size = digs + 1; + return MP_OKAY; +} + +#endif + +/* $Source: /cvs/libtom/libtommath/bn_mp_radix_size.c,v $ */ +/* $Revision: 1.4 $ */ +/* $Date: 2006/03/31 14:18:44 $ */ |