1 /*	$NetBSD: bn_mp_toradix.c,v 1.1.1.1 2011/04/13 18:14:55 elric Exp $	*/
2 
3 #include <tommath.h>
4 #ifdef BN_MP_TORADIX_C
5 /* LibTomMath, multiple-precision integer library -- Tom St Denis
6  *
7  * LibTomMath is a library that provides multiple-precision
8  * integer arithmetic as well as number theoretic functionality.
9  *
10  * The library was designed directly after the MPI library by
11  * Michael Fromberger but has been written from scratch with
12  * additional optimizations in place.
13  *
14  * The library is free for all purposes without any express
15  * guarantee it works.
16  *
17  * Tom St Denis, tomstdenis@gmail.com, http://libtom.org
18  */
19 
20 /* stores a bignum as a ASCII string in a given radix (2..64) */
21 int mp_toradix (mp_int * a, char *str, int radix)
22 {
23   int     res, digs;
24   mp_int  t;
25   mp_digit d;
26   char   *_s = str;
27 
28   /* check range of the radix */
29   if (radix < 2 || radix > 64) {
30     return MP_VAL;
31   }
32 
33   /* quick out if its zero */
34   if (mp_iszero(a) == 1) {
35      *str++ = '0';
36      *str = '\0';
37      return MP_OKAY;
38   }
39 
40   if ((res = mp_init_copy (&t, a)) != MP_OKAY) {
41     return res;
42   }
43 
44   /* if it is negative output a - */
45   if (t.sign == MP_NEG) {
46     ++_s;
47     *str++ = '-';
48     t.sign = MP_ZPOS;
49   }
50 
51   digs = 0;
52   while (mp_iszero (&t) == 0) {
53     if ((res = mp_div_d (&t, (mp_digit) radix, &t, &d)) != MP_OKAY) {
54       mp_clear (&t);
55       return res;
56     }
57     *str++ = mp_s_rmap[d];
58     ++digs;
59   }
60 
61   /* reverse the digits of the string.  In this case _s points
62    * to the first digit [exluding the sign] of the number]
63    */
64   bn_reverse ((unsigned char *)_s, digs);
65 
66   /* append a NULL so the string is properly terminated */
67   *str = '\0';
68 
69   mp_clear (&t);
70   return MP_OKAY;
71 }
72 
73 #endif
74 
75 /* Source: /cvs/libtom/libtommath/bn_mp_toradix.c,v */
76 /* Revision: 1.4 */
77 /* Date: 2006/12/28 01:25:13 */
78