1 | #include <tommath.h> |
---|
2 | #ifdef BN_MP_GROW_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://math.libtomcrypt.com |
---|
16 | */ |
---|
17 | |
---|
18 | /* grow as required */ |
---|
19 | int mp_grow (mp_int * a, int size) |
---|
20 | { |
---|
21 | int i; |
---|
22 | mp_digit *tmp; |
---|
23 | |
---|
24 | /* if the alloc size is smaller alloc more ram */ |
---|
25 | if (a->alloc < size) { |
---|
26 | /* ensure there are always at least MP_PREC digits extra on top */ |
---|
27 | size += (MP_PREC * 2) - (size % MP_PREC); |
---|
28 | |
---|
29 | /* reallocate the array a->dp |
---|
30 | * |
---|
31 | * We store the return in a temporary variable |
---|
32 | * in case the operation failed we don't want |
---|
33 | * to overwrite the dp member of a. |
---|
34 | */ |
---|
35 | tmp = OPT_CAST(mp_digit) XREALLOC (a->dp, sizeof (mp_digit) * size); |
---|
36 | if (tmp == NULL) { |
---|
37 | /* reallocation failed but "a" is still valid [can be freed] */ |
---|
38 | return MP_MEM; |
---|
39 | } |
---|
40 | |
---|
41 | /* reallocation succeeded so set a->dp */ |
---|
42 | a->dp = tmp; |
---|
43 | |
---|
44 | /* zero excess digits */ |
---|
45 | i = a->alloc; |
---|
46 | a->alloc = size; |
---|
47 | for (; i < a->alloc; i++) { |
---|
48 | a->dp[i] = 0; |
---|
49 | } |
---|
50 | } |
---|
51 | return MP_OKAY; |
---|
52 | } |
---|
53 | #endif |
---|
54 | |
---|
55 | /* $Source: /cvsroot/tcl/libtommath/bn_mp_grow.c,v $ */ |
---|
56 | /* $Revision: 1.1.1.3 $ */ |
---|
57 | /* $Date: 2006/12/01 00:08:11 $ */ |
---|