79 lines
1.7 KiB
C
79 lines
1.7 KiB
C
#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://libtom.org
|
|
*/
|
|
|
|
/* 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
|
|
|
|
/* $Source$ */
|
|
/* $Revision$ */
|
|
/* $Date$ */
|