1 /*	$NetBSD: bn_mp_fread.c,v 1.1.1.1 2011/04/13 18:14:54 elric Exp $	*/
2 
3 #include <tommath.h>
4 #ifdef BN_MP_FREAD_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 /* read a bigint from a file stream in ASCII */
21 int mp_fread(mp_int *a, int radix, FILE *stream)
22 {
23    int err, ch, neg, y;
24 
25    /* clear a */
26    mp_zero(a);
27 
28    /* if first digit is - then set negative */
29    ch = fgetc(stream);
30    if (ch == '-') {
31       neg = MP_NEG;
32       ch = fgetc(stream);
33    } else {
34       neg = MP_ZPOS;
35    }
36 
37    for (;;) {
38       /* find y in the radix map */
39       for (y = 0; y < radix; y++) {
40           if (mp_s_rmap[y] == ch) {
41              break;
42           }
43       }
44       if (y == radix) {
45          break;
46       }
47 
48       /* shift up and add */
49       if ((err = mp_mul_d(a, radix, a)) != MP_OKAY) {
50          return err;
51       }
52       if ((err = mp_add_d(a, y, a)) != MP_OKAY) {
53          return err;
54       }
55 
56       ch = fgetc(stream);
57    }
58    if (mp_cmp_d(a, 0) != MP_EQ) {
59       a->sign = neg;
60    }
61 
62    return MP_OKAY;
63 }
64 
65 #endif
66 
67 /* Source: /cvs/libtom/libtommath/bn_mp_fread.c,v */
68 /* Revision: 1.4 */
69 /* Date: 2006/12/28 01:25:13 */
70