1 /* $NetBSD: bn_mp_fread.c,v 1.2 2017/01/28 21:31:47 christos 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 */
mp_fread(mp_int * a,int radix,FILE * stream)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