bn_mp_to_unsigned_bin.c
1.23 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
#include <tommath.h>
#ifdef BN_MP_TO_UNSIGNED_BIN_C
/* LibTomMath, multiple-precision integer library -- Tom St Denis
*
* LibTomMath is a library that provides multiple-precision
* integer arithmetic as well as number theoretic functionality.
*
* The library was designed directly after the MPI library by
* Michael Fromberger but has been written from scratch with
* additional optimizations in place.
*
* The library is free for all purposes without any express
* guarantee it works.
*
* Tom St Denis, tomstdenis@gmail.com, http://math.libtomcrypt.com
*/
/* store in unsigned [big endian] format */
int mp_to_unsigned_bin (mp_int * a, unsigned char *b)
{
int x, res;
mp_int t;
if ((res = mp_init_copy (&t, a)) != MP_OKAY) {
return res;
}
x = 0;
while (mp_iszero (&t) == 0) {
#ifndef MP_8BIT
b[x++] = (unsigned char) (t.dp[0] & 255);
#else
b[x++] = (unsigned char) (t.dp[0] | ((t.dp[1] & 0x01) << 7));
#endif
if ((res = mp_div_2d (&t, 8, &t, NULL)) != MP_OKAY) {
mp_clear (&t);
return res;
}
}
bn_reverse (b, x);
mp_clear (&t);
return MP_OKAY;
}
#endif
/* $Source: /cvs/libtom/libtommath/bn_mp_to_unsigned_bin.c,v $ */
/* $Revision: 1.3 $ */
/* $Date: 2006/03/31 14:18:44 $ */