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#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
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