89 lines
2.0 KiB
C
89 lines
2.0 KiB
C
#include <tommath.h>
|
|
#ifdef BN_MP_TORADIX_N_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
|
|
*/
|
|
|
|
/* stores a bignum as a ASCII string in a given radix (2..64)
|
|
*
|
|
* Stores upto maxlen-1 chars and always a NULL byte
|
|
*/
|
|
int mp_toradix_n(mp_int * a, char *str, int radix, int maxlen)
|
|
{
|
|
int res, digs;
|
|
mp_int t;
|
|
mp_digit d;
|
|
char *_s = str;
|
|
|
|
/* check range of the maxlen, radix */
|
|
if (maxlen < 2 || radix < 2 || radix > 64) {
|
|
return MP_VAL;
|
|
}
|
|
|
|
/* quick out if its zero */
|
|
if (mp_iszero(a) == MP_YES) {
|
|
*str++ = '0';
|
|
*str = '\0';
|
|
return MP_OKAY;
|
|
}
|
|
|
|
if ((res = mp_init_copy (&t, a)) != MP_OKAY) {
|
|
return res;
|
|
}
|
|
|
|
/* if it is negative output a - */
|
|
if (t.sign == MP_NEG) {
|
|
/* we have to reverse our digits later... but not the - sign!! */
|
|
++_s;
|
|
|
|
/* store the flag and mark the number as positive */
|
|
*str++ = '-';
|
|
t.sign = MP_ZPOS;
|
|
|
|
/* subtract a char */
|
|
--maxlen;
|
|
}
|
|
|
|
digs = 0;
|
|
while (mp_iszero (&t) == 0) {
|
|
if (--maxlen < 1) {
|
|
/* no more room */
|
|
break;
|
|
}
|
|
if ((res = mp_div_d (&t, (mp_digit) radix, &t, &d)) != MP_OKAY) {
|
|
mp_clear (&t);
|
|
return res;
|
|
}
|
|
*str++ = mp_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';
|
|
|
|
mp_clear (&t);
|
|
return MP_OKAY;
|
|
}
|
|
|
|
#endif
|
|
|
|
/* $Source$ */
|
|
/* $Revision$ */
|
|
/* $Date$ */
|