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comparison bn_mp_copy.c @ 2:86e0b50a9b58 libtommath-orig ltm-0.30-orig

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ltm 0.30 orig import
author Matt Johnston <matt@ucc.asn.au>
date Mon, 31 May 2004 18:25:22 +0000
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children d29b64170cf0
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-1:000000000000 2:86e0b50a9b58
1 /* LibTomMath, multiple-precision integer library -- Tom St Denis
2 *
3 * LibTomMath is a library that provides multiple-precision
4 * integer arithmetic as well as number theoretic functionality.
5 *
6 * The library was designed directly after the MPI library by
7 * Michael Fromberger but has been written from scratch with
8 * additional optimizations in place.
9 *
10 * The library is free for all purposes without any express
11 * guarantee it works.
12 *
13 * Tom St Denis, [email protected], http://math.libtomcrypt.org
14 */
15 #include <tommath.h>
16
17 /* copy, b = a */
18 int
19 mp_copy (mp_int * a, mp_int * b)
20 {
21 int res, n;
22
23 /* if dst == src do nothing */
24 if (a == b) {
25 return MP_OKAY;
26 }
27
28 /* grow dest */
29 if (b->alloc < a->used) {
30 if ((res = mp_grow (b, a->used)) != MP_OKAY) {
31 return res;
32 }
33 }
34
35 /* zero b and copy the parameters over */
36 {
37 register mp_digit *tmpa, *tmpb;
38
39 /* pointer aliases */
40
41 /* source */
42 tmpa = a->dp;
43
44 /* destination */
45 tmpb = b->dp;
46
47 /* copy all the digits */
48 for (n = 0; n < a->used; n++) {
49 *tmpb++ = *tmpa++;
50 }
51
52 /* clear high digits */
53 for (; n < b->used; n++) {
54 *tmpb++ = 0;
55 }
56 }
57
58 /* copy used count and sign */
59 b->used = a->used;
60 b->sign = a->sign;
61 return MP_OKAY;
62 }