denyhosts/clamscan/libclamav/tomsfastmath/bin/fp_toradix_n.c

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2022-10-22 18:41:00 +08:00
/* TomsFastMath, a fast ISO C bignum library.
* That project is public domain and free for all purposes.
* fp_toradix_n included in TomsFastMath specification (tfm.h), but unimplemented until now.
* It is based on conversion of mp_toradix_n from libtommath
* Will send the body of this function back to the LibTom projects, if they want it
*/
#include "bignum_fast.h"
int fp_toradix_n(fp_int *a, char *str, int radix, int maxlen)
{
int digs;
fp_int t;
fp_digit d;
char *_s = str;
/* check range of the maxlen, radix */
if (maxlen < 2 || 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;
--maxlen;
}
digs = 0;
while (fp_iszero (&t) == FP_NO) {
if (--maxlen < 1) {
/* no more room */
break;
}
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]
*/
fp_reverse ((unsigned char *)_s, digs);
/* append a NULL so the string is properly terminated */
*str = '\0';
return FP_OKAY;
}