1#include <tommath.h>
2#ifdef BN_MP_RAND_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://libtom.org
16 */
17
18/* makes a pseudo-random int of a given size */
19int
20mp_rand (mp_int * a, int digits)
21{
22  int     res;
23  mp_digit d;
24
25  mp_zero (a);
26  if (digits <= 0) {
27    return MP_OKAY;
28  }
29
30  /* first place a random non-zero digit */
31  do {
32    d = ((mp_digit) abs (rand ())) & MP_MASK;
33  } while (d == 0);
34
35  if ((res = mp_add_d (a, d, a)) != MP_OKAY) {
36    return res;
37  }
38
39  while (--digits > 0) {
40    if ((res = mp_lshd (a, 1)) != MP_OKAY) {
41      return res;
42    }
43
44    if ((res = mp_add_d (a, ((mp_digit) abs (rand ())), a)) != MP_OKAY) {
45      return res;
46    }
47  }
48
49  return MP_OKAY;
50}
51#endif
52
53/* $Source: /cvs/libtom/libtommath/bn_mp_rand.c,v $ */
54/* $Revision: 1.4 $ */
55/* $Date: 2006/12/28 01:25:13 $ */
56