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author | William Joye <wjoye@cfa.harvard.edu> | 2016-10-18 17:31:11 (GMT) |
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committer | William Joye <wjoye@cfa.harvard.edu> | 2016-10-18 17:31:11 (GMT) |
commit | 066971b1e6e77991d9161bb0216a63ba94ea04f9 (patch) | |
tree | 6de02f79b7a4bb08a329581aa67b444fb9001bfd /tcl8.6/libtommath/bn_mp_radix_size.c | |
parent | ba065c2de121da1c1dfddd0aa587d10e7e150f05 (diff) | |
parent | 9966985d896629eede849a84f18e406d1164a16c (diff) | |
download | blt-066971b1e6e77991d9161bb0216a63ba94ea04f9.zip blt-066971b1e6e77991d9161bb0216a63ba94ea04f9.tar.gz blt-066971b1e6e77991d9161bb0216a63ba94ea04f9.tar.bz2 |
Merge commit '9966985d896629eede849a84f18e406d1164a16c' as 'tcl8.6'
Diffstat (limited to 'tcl8.6/libtommath/bn_mp_radix_size.c')
-rw-r--r-- | tcl8.6/libtommath/bn_mp_radix_size.c | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/tcl8.6/libtommath/bn_mp_radix_size.c b/tcl8.6/libtommath/bn_mp_radix_size.c new file mode 100644 index 0000000..40c4d04 --- /dev/null +++ b/tcl8.6/libtommath/bn_mp_radix_size.c @@ -0,0 +1,83 @@ +#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. + * mp_toradix_n requires a minimum of 3 bytes, so never report less than + * that. + */ + + if ( digs >= 2 ) { + *size = digs + 1; + } else { + *size = 3; + } + return MP_OKAY; +} + +#endif |