1 /*	$NetBSD: bn_mp_grow.c,v 1.1.1.2 2014/04/24 12:45:31 pettai Exp $	*/
2 
3 #include <tommath.h>
4 #ifdef BN_MP_GROW_C
5 /* LibTomMath, multiple-precision integer library -- Tom St Denis
6  *
7  * LibTomMath is a library that provides multiple-precision
8  * integer arithmetic as well as number theoretic functionality.
9  *
10  * The library was designed directly after the MPI library by
11  * Michael Fromberger but has been written from scratch with
12  * additional optimizations in place.
13  *
14  * The library is free for all purposes without any express
15  * guarantee it works.
16  *
17  * Tom St Denis, tomstdenis@gmail.com, http://libtom.org
18  */
19 
20 /* grow as required */
mp_grow(mp_int * a,int size)21 int mp_grow (mp_int * a, int size)
22 {
23   int     i;
24   mp_digit *tmp;
25 
26   /* if the alloc size is smaller alloc more ram */
27   if (a->alloc < size) {
28     /* ensure there are always at least MP_PREC digits extra on top */
29     size += (MP_PREC * 2) - (size % MP_PREC);
30 
31     /* reallocate the array a->dp
32      *
33      * We store the return in a temporary variable
34      * in case the operation failed we don't want
35      * to overwrite the dp member of a.
36      */
37     tmp = OPT_CAST(mp_digit) XREALLOC (a->dp, sizeof (mp_digit) * size);
38     if (tmp == NULL) {
39       /* reallocation failed but "a" is still valid [can be freed] */
40       return MP_MEM;
41     }
42 
43     /* reallocation succeeded so set a->dp */
44     a->dp = tmp;
45 
46     /* zero excess digits */
47     i        = a->alloc;
48     a->alloc = size;
49     for (; i < a->alloc; i++) {
50       a->dp[i] = 0;
51     }
52   }
53   return MP_OKAY;
54 }
55 #endif
56 
57 /* Source: /cvs/libtom/libtommath/bn_mp_grow.c,v  */
58 /* Revision: 1.4  */
59 /* Date: 2006/12/28 01:25:13  */
60