tommath/bn_mp_toradix.c

76 lines
1.7 KiB
C
Raw Normal View History

#include <tommath_private.h>
2004-10-29 18:07:18 -04:00
#ifdef BN_MP_TORADIX_C
2003-07-02 11:39:39 -04:00
/* LibTomMath, multiple-precision integer library -- Tom St Denis
*
2003-08-04 21:24:44 -04:00
* LibTomMath is a library that provides multiple-precision
2003-07-02 11:39:39 -04:00
* integer arithmetic as well as number theoretic functionality.
*
2003-08-04 21:24:44 -04:00
* The library was designed directly after the MPI library by
2003-07-02 11:39:39 -04:00
* 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, tstdenis82@gmail.com, http://libtom.org
2003-07-02 11:39:39 -04:00
*/
/* stores a bignum as a ASCII string in a given radix (2..64) */
2004-01-25 12:40:21 -05:00
int mp_toradix (mp_int * a, char *str, int radix)
2003-07-02 11:39:39 -04:00
{
int res, digs;
mp_int t;
mp_digit d;
char *_s = str;
2003-12-24 13:59:22 -05:00
/* check range of the radix */
if ((radix < 2) || (radix > 64)) {
2003-07-02 11:39:39 -04:00
return MP_VAL;
}
2003-12-24 13:59:22 -05:00
2003-07-02 11:39:39 -04:00
/* quick out if its zero */
2015-10-25 11:34:43 -04:00
if (mp_iszero(a) == MP_YES) {
2003-07-02 11:39:39 -04:00
*str++ = '0';
*str = '\0';
return MP_OKAY;
}
2003-12-24 13:59:22 -05:00
2003-07-02 11:39:39 -04:00
if ((res = mp_init_copy (&t, a)) != MP_OKAY) {
return res;
}
/* if it is negative output a - */
if (t.sign == MP_NEG) {
++_s;
*str++ = '-';
t.sign = MP_ZPOS;
}
digs = 0;
2015-10-25 11:34:43 -04:00
while (mp_iszero (&t) == MP_NO) {
2003-07-02 11:39:39 -04:00
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);
2003-12-24 13:59:22 -05:00
2003-07-02 11:39:39 -04:00
/* append a NULL so the string is properly terminated */
2003-12-24 13:59:22 -05:00
*str = '\0';
2003-07-02 11:39:39 -04:00
mp_clear (&t);
return MP_OKAY;
}
2004-10-29 18:07:18 -04:00
#endif
2005-08-01 12:37:28 -04:00
/* $Source$ */
/* $Revision$ */
/* $Date$ */