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comparison libtommath/bn_mp_copy.c @ 284:eed26cff980b

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propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583) to branch 'au.asn.ucc.matt.dropbear' (head fff0894a0399405a9410ea1c6d118f342cf2aa64)
author Matt Johnston <matt@ucc.asn.au>
date Wed, 08 Mar 2006 13:23:49 +0000
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children 5ff8218bcee9
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283:bd240aa12ba7 284:eed26cff980b
1 #include <tommath.h>
2 #ifdef BN_MP_COPY_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 /* copy, b = a */
19 int
20 mp_copy (mp_int * a, mp_int * b)
21 {
22 int res, n;
23
24 /* if dst == src do nothing */
25 if (a == b) {
26 return MP_OKAY;
27 }
28
29 /* grow dest */
30 if (b->alloc < a->used) {
31 if ((res = mp_grow (b, a->used)) != MP_OKAY) {
32 return res;
33 }
34 }
35
36 /* zero b and copy the parameters over */
37 {
38 register mp_digit *tmpa, *tmpb;
39
40 /* pointer aliases */
41
42 /* source */
43 tmpa = a->dp;
44
45 /* destination */
46 tmpb = b->dp;
47
48 /* copy all the digits */
49 for (n = 0; n < a->used; n++) {
50 *tmpb++ = *tmpa++;
51 }
52
53 /* clear high digits */
54 for (; n < b->used; n++) {
55 *tmpb++ = 0;
56 }
57 }
58
59 /* copy used count and sign */
60 b->used = a->used;
61 b->sign = a->sign;
62 return MP_OKAY;
63 }
64 #endif