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comparison bn_mp_toradix.c @ 282:91fbc376f010 libtommath-orig libtommath-0.35

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Import of libtommath 0.35 From ltm-0.35.tar.bz2 SHA1 of 3f193dbae9351e92d02530994fa18236f7fde01c
author Matt Johnston <matt@ucc.asn.au>
date Wed, 08 Mar 2006 13:16:18 +0000
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children 97db060d0ef5
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-1:000000000000 282:91fbc376f010
1 #include <tommath.h>
2 #ifdef BN_MP_TORADIX_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, [email protected], http://math.libtomcrypt.org
16 */
17
18 /* stores a bignum as a ASCII string in a given radix (2..64) */
19 int mp_toradix (mp_int * a, char *str, int radix)
20 {
21 int res, digs;
22 mp_int t;
23 mp_digit d;
24 char *_s = str;
25
26 /* check range of the radix */
27 if (radix < 2 || radix > 64) {
28 return MP_VAL;
29 }
30
31 /* quick out if its zero */
32 if (mp_iszero(a) == 1) {
33 *str++ = '0';
34 *str = '\0';
35 return MP_OKAY;
36 }
37
38 if ((res = mp_init_copy (&t, a)) != MP_OKAY) {
39 return res;
40 }
41
42 /* if it is negative output a - */
43 if (t.sign == MP_NEG) {
44 ++_s;
45 *str++ = '-';
46 t.sign = MP_ZPOS;
47 }
48
49 digs = 0;
50 while (mp_iszero (&t) == 0) {
51 if ((res = mp_div_d (&t, (mp_digit) radix, &t, &d)) != MP_OKAY) {
52 mp_clear (&t);
53 return res;
54 }
55 *str++ = mp_s_rmap[d];
56 ++digs;
57 }
58
59 /* reverse the digits of the string. In this case _s points
60 * to the first digit [exluding the sign] of the number]
61 */
62 bn_reverse ((unsigned char *)_s, digs);
63
64 /* append a NULL so the string is properly terminated */
65 *str = '\0';
66
67 mp_clear (&t);
68 return MP_OKAY;
69 }
70
71 #endif