blob: af94be8676ab6e16f0c1c7edd0aa2e5995f654bb (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
|
#include <tommath.h>
#ifdef BN_MP_RADIX_SIZE_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
*/
/* returns size of ASCII reprensentation */
int mp_radix_size (mp_int * a, int radix, int *size)
{
int res, digs;
mp_int t;
mp_digit d;
*size = 0;
/* special case for binary */
if (radix == 2) {
*size = mp_count_bits (a) + (a->sign == MP_NEG ? 1 : 0) + 1;
return MP_OKAY;
}
/* make sure the radix is in range */
if (radix < 2 || radix > 64) {
return MP_VAL;
}
if (mp_iszero(a) == MP_YES) {
*size = 2;
return MP_OKAY;
}
/* digs is the digit count */
digs = 0;
/* if it's negative add one for the sign */
if (a->sign == MP_NEG) {
++digs;
}
/* init a copy of the input */
if ((res = mp_init_copy (&t, a)) != MP_OKAY) {
return res;
}
/* force temp to positive */
t.sign = MP_ZPOS;
/* fetch out all of the digits */
while (mp_iszero (&t) == MP_NO) {
if ((res = mp_div_d (&t, (mp_digit) radix, &t, &d)) != MP_OKAY) {
mp_clear (&t);
return res;
}
++digs;
}
mp_clear (&t);
/* return digs + 1, the 1 is for the NULL byte that would be required. */
*size = digs + 1;
return MP_OKAY;
}
#endif
/* $Source: /cvs/libtom/libtommath/bn_mp_radix_size.c,v $ */
/* $Revision: 1.5 $ */
/* $Date: 2006/12/28 01:25:13 $ */
|
