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comparison libtommath/bn_mp_read_unsigned_bin.c @ 399:a707e6148060

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merge of '5fdf69ca60d1683cdd9f4c2595134bed26394834' and '6b61c50f4cf888bea302ac8fcf5dbb573b443251'
author Matt Johnston <matt@ucc.asn.au>
date Sat, 03 Feb 2007 08:20:34 +0000
parents 5ff8218bcee9
children 60fc6476e044
comparison
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394:17d097fc111c 399:a707e6148060
1 #include <tommath.h>
2 #ifdef BN_MP_READ_UNSIGNED_BIN_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.com
16 */
17
18 /* reads a unsigned char array, assumes the msb is stored first [big endian] */
19 int mp_read_unsigned_bin (mp_int * a, const unsigned char *b, int c)
20 {
21 int res;
22
23 /* make sure there are at least two digits */
24 if (a->alloc < 2) {
25 if ((res = mp_grow(a, 2)) != MP_OKAY) {
26 return res;
27 }
28 }
29
30 /* zero the int */
31 mp_zero (a);
32
33 /* read the bytes in */
34 while (c-- > 0) {
35 if ((res = mp_mul_2d (a, 8, a)) != MP_OKAY) {
36 return res;
37 }
38
39 #ifndef MP_8BIT
40 a->dp[0] |= *b++;
41 a->used += 1;
42 #else
43 a->dp[0] = (*b & MP_MASK);
44 a->dp[1] |= ((*b++ >> 7U) & 1);
45 a->used += 2;
46 #endif
47 }
48 mp_clamp (a);
49 return MP_OKAY;
50 }
51 #endif
52
53 /* $Source: /cvs/libtom/libtommath/bn_mp_read_unsigned_bin.c,v $ */
54 /* $Revision: 1.4 $ */
55 /* $Date: 2006/03/31 14:18:44 $ */