1#include <tommath.h>
2#ifdef BN_MP_RADIX_SIZE_C
3/* LibTomMath, multiple-precision integer library -- Tom St Denis
4 *
5 * LibTomMath is a library that provides multiple-precision
6 * integer arithmetic as well as number theoretic functionality.
7 *
8 * The library was designed directly after the MPI library by
9 * Michael Fromberger but has been written from scratch with
10 * additional optimizations in place.
11 *
12 * The library is free for all purposes without any express
13 * guarantee it works.
14 *
15 * Tom St Denis, tomstdenis@gmail.com, http://libtom.org
16 */
17
18/* returns size of ASCII reprensentation */
19int mp_radix_size (mp_int * a, int radix, int *size)
20{
21  int     res, digs;
22  mp_int  t;
23  mp_digit d;
24
25  *size = 0;
26
27  /* special case for binary */
28  if (radix == 2) {
29    *size = mp_count_bits (a) + (a->sign == MP_NEG ? 1 : 0) + 1;
30    return MP_OKAY;
31  }
32
33  /* make sure the radix is in range */
34  if (radix < 2 || radix > 64) {
35    return MP_VAL;
36  }
37
38  if (mp_iszero(a) == MP_YES) {
39    *size = 2;
40    return MP_OKAY;
41  }
42
43  /* digs is the digit count */
44  digs = 0;
45
46  /* if it's negative add one for the sign */
47  if (a->sign == MP_NEG) {
48    ++digs;
49  }
50
51  /* init a copy of the input */
52  if ((res = mp_init_copy (&t, a)) != MP_OKAY) {
53    return res;
54  }
55
56  /* force temp to positive */
57  t.sign = MP_ZPOS;
58
59  /* fetch out all of the digits */
60  while (mp_iszero (&t) == MP_NO) {
61    if ((res = mp_div_d (&t, (mp_digit) radix, &t, &d)) != MP_OKAY) {
62      mp_clear (&t);
63      return res;
64    }
65    ++digs;
66  }
67  mp_clear (&t);
68
69  /* return digs + 1, the 1 is for the NULL byte that would be required. */
70  *size = digs + 1;
71  return MP_OKAY;
72}
73
74#endif
75
76/* $Source$ */
77/* $Revision$ */
78/* $Date$ */
79