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comparison bn_mp_fread.c @ 2:86e0b50a9b58 libtommath-orig ltm-0.30-orig

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ltm 0.30 orig import
author Matt Johnston <matt@ucc.asn.au>
date Mon, 31 May 2004 18:25:22 +0000
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children d29b64170cf0
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-1:000000000000 2:86e0b50a9b58
1 /* LibTomMath, multiple-precision integer library -- Tom St Denis
2 *
3 * LibTomMath is a library that provides multiple-precision
4 * integer arithmetic as well as number theoretic functionality.
5 *
6 * The library was designed directly after the MPI library by
7 * Michael Fromberger but has been written from scratch with
8 * additional optimizations in place.
9 *
10 * The library is free for all purposes without any express
11 * guarantee it works.
12 *
13 * Tom St Denis, [email protected], http://math.libtomcrypt.org
14 */
15 #include <tommath.h>
16
17 /* read a bigint from a file stream in ASCII */
18 int mp_fread(mp_int *a, int radix, FILE *stream)
19 {
20 int err, ch, neg, y;
21
22 /* clear a */
23 mp_zero(a);
24
25 /* if first digit is - then set negative */
26 ch = fgetc(stream);
27 if (ch == '-') {
28 neg = MP_NEG;
29 ch = fgetc(stream);
30 } else {
31 neg = MP_ZPOS;
32 }
33
34 for (;;) {
35 /* find y in the radix map */
36 for (y = 0; y < radix; y++) {
37 if (mp_s_rmap[y] == ch) {
38 break;
39 }
40 }
41 if (y == radix) {
42 break;
43 }
44
45 /* shift up and add */
46 if ((err = mp_mul_d(a, radix, a)) != MP_OKAY) {
47 return err;
48 }
49 if ((err = mp_add_d(a, y, a)) != MP_OKAY) {
50 return err;
51 }
52
53 ch = fgetc(stream);
54 }
55 if (mp_cmp_d(a, 0) != MP_EQ) {
56 a->sign = neg;
57 }
58
59 return MP_OKAY;
60 }
61