tomsfastmath/fp_toradix.c
2010-07-22 10:06:21 +02:00

56 lines
1.1 KiB
C

/* TomsFastMath, a fast ISO C bignum library.
*
* This project is meant to fill in where LibTomMath
* falls short. That is speed ;-)
*
* This project is public domain and free for all purposes.
*
* Tom St Denis, tomstdenis@iahu.ca
*/
#include <tfm.h>
int fp_toradix(fp_int *a, char *str, int radix)
{
int digs;
fp_int t;
fp_digit d;
char *_s = str;
/* check range of the radix */
if (radix < 2 || radix > 64) {
return FP_VAL;
}
/* quick out if its zero */
if (fp_iszero(a) == 1) {
*str++ = '0';
*str = '\0';
return FP_OKAY;
}
fp_init_copy(&t, a);
/* if it is negative output a - */
if (t.sign == FP_NEG) {
++_s;
*str++ = '-';
t.sign = FP_ZPOS;
}
digs = 0;
while (fp_iszero (&t) == FP_NO) {
fp_div_d (&t, (fp_digit) radix, &t, &d);
*str++ = fp_s_rmap[d];
++digs;
}
/* reverse the digits of the string. In this case _s points
* to the first digit [exluding the sign] of the number]
*/
bn_reverse ((unsigned char *)_s, digs);
/* append a NULL so the string is properly terminated */
*str = '\0';
return FP_OKAY;
}