/* 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@iahu.ca, http://math.libtomcrypt.org
*/
#include <tommath.h>
/* returns size of ASCII reprensentation */
int
mp_radix_size (mp_int * a, int radix)
{
int res, digs;
mp_int t;
mp_digit d;
/* special case for binary */
if (radix == 2) {
return mp_count_bits (a) + (a->sign == MP_NEG ? 1 : 0) + 1;
}
/* make sure the radix is in range */
if (radix < 2 || radix > 64) {
return 0;
}
/* init a copy of the input */
if ((res = mp_init_copy (&t, a)) != MP_OKAY) {
return 0;
}
/* digs is the digit count */
digs = 0;
/* if it's negative add one for the sign */
if (t.sign == MP_NEG) {
++digs;
t.sign = MP_ZPOS;
}
/* fetch out all of the digits */
while (mp_iszero (&t) == 0) {
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. */
return digs + 1;
}
