1 /* $NetBSD: bn_mp_read_unsigned_bin.c,v 1.1.1.2 2014/04/24 12:45:31 pettai Exp $ */
2
3 #include <tommath.h>
4 #ifdef BN_MP_READ_UNSIGNED_BIN_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 /* reads a unsigned char array, assumes the msb is stored first [big endian] */
mp_read_unsigned_bin(mp_int * a,const unsigned char * b,int c)21 int mp_read_unsigned_bin (mp_int * a, const unsigned char *b, int c)
22 {
23 int res;
24
25 /* make sure there are at least two digits */
26 if (a->alloc < 2) {
27 if ((res = mp_grow(a, 2)) != MP_OKAY) {
28 return res;
29 }
30 }
31
32 /* zero the int */
33 mp_zero (a);
34
35 /* read the bytes in */
36 while (c-- > 0) {
37 if ((res = mp_mul_2d (a, 8, a)) != MP_OKAY) {
38 return res;
39 }
40
41 #ifndef MP_8BIT
42 a->dp[0] |= *b++;
43 a->used += 1;
44 #else
45 a->dp[0] = (*b & MP_MASK);
46 a->dp[1] |= ((*b++ >> 7U) & 1);
47 a->used += 2;
48 #endif
49 }
50 mp_clamp (a);
51 return MP_OKAY;
52 }
53 #endif
54
55 /* Source: /cvs/libtom/libtommath/bn_mp_read_unsigned_bin.c,v */
56 /* Revision: 1.5 */
57 /* Date: 2006/12/28 01:25:13 */
58