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comparison libtommath/bn_mp_fread.c @ 284:eed26cff980b

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propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583) to branch 'au.asn.ucc.matt.dropbear' (head fff0894a0399405a9410ea1c6d118f342cf2aa64)
author Matt Johnston <matt@ucc.asn.au>
date Wed, 08 Mar 2006 13:23:49 +0000
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children 5ff8218bcee9
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283:bd240aa12ba7 284:eed26cff980b
1 #include <tommath.h>
2 #ifdef BN_MP_FREAD_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, [email protected], http://math.libtomcrypt.org
16 */
17
18 /* read a bigint from a file stream in ASCII */
19 int mp_fread(mp_int *a, int radix, FILE *stream)
20 {
21 int err, ch, neg, y;
22
23 /* clear a */
24 mp_zero(a);
25
26 /* if first digit is - then set negative */
27 ch = fgetc(stream);
28 if (ch == '-') {
29 neg = MP_NEG;
30 ch = fgetc(stream);
31 } else {
32 neg = MP_ZPOS;
33 }
34
35 for (;;) {
36 /* find y in the radix map */
37 for (y = 0; y < radix; y++) {
38 if (mp_s_rmap[y] == ch) {
39 break;
40 }
41 }
42 if (y == radix) {
43 break;
44 }
45
46 /* shift up and add */
47 if ((err = mp_mul_d(a, radix, a)) != MP_OKAY) {
48 return err;
49 }
50 if ((err = mp_add_d(a, y, a)) != MP_OKAY) {
51 return err;
52 }
53
54 ch = fgetc(stream);
55 }
56 if (mp_cmp_d(a, 0) != MP_EQ) {
57 a->sign = neg;
58 }
59
60 return MP_OKAY;
61 }
62
63 #endif