1/*	$NetBSD: bn_mp_toradix_n.c,v 1.1.1.1 2011/04/13 18:14:55 elric Exp $	*/
2
3#include <tommath.h>
4#ifdef BN_MP_TORADIX_N_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 *
22 * Stores upto maxlen-1 chars and always a NULL byte
23 */
24int mp_toradix_n(mp_int * a, char *str, int radix, int maxlen)
25{
26  int     res, digs;
27  mp_int  t;
28  mp_digit d;
29  char   *_s = str;
30
31  /* check range of the maxlen, radix */
32  if (maxlen < 2 || radix < 2 || radix > 64) {
33    return MP_VAL;
34  }
35
36  /* quick out if its zero */
37  if (mp_iszero(a) == MP_YES) {
38     *str++ = '0';
39     *str = '\0';
40     return MP_OKAY;
41  }
42
43  if ((res = mp_init_copy (&t, a)) != MP_OKAY) {
44    return res;
45  }
46
47  /* if it is negative output a - */
48  if (t.sign == MP_NEG) {
49    /* we have to reverse our digits later... but not the - sign!! */
50    ++_s;
51
52    /* store the flag and mark the number as positive */
53    *str++ = '-';
54    t.sign = MP_ZPOS;
55
56    /* subtract a char */
57    --maxlen;
58  }
59
60  digs = 0;
61  while (mp_iszero (&t) == 0) {
62    if (--maxlen < 1) {
63       /* no more room */
64       break;
65    }
66    if ((res = mp_div_d (&t, (mp_digit) radix, &t, &d)) != MP_OKAY) {
67      mp_clear (&t);
68      return res;
69    }
70    *str++ = mp_s_rmap[d];
71    ++digs;
72  }
73
74  /* reverse the digits of the string.  In this case _s points
75   * to the first digit [exluding the sign] of the number
76   */
77  bn_reverse ((unsigned char *)_s, digs);
78
79  /* append a NULL so the string is properly terminated */
80  *str = '\0';
81
82  mp_clear (&t);
83  return MP_OKAY;
84}
85
86#endif
87
88/* Source: /cvs/libtom/libtommath/bn_mp_toradix_n.c,v */
89/* Revision: 1.5 */
90/* Date: 2006/12/28 01:25:13 */
91