6663b6c9
 adorian
projet complet av...
|
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
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
|
#include <tommath.h>
#ifdef BN_MP_READ_RADIX_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
*/
/* read a string [ASCII] in a given radix */
int mp_read_radix (mp_int * a, const char *str, int radix)
{
int y, res, neg;
char ch;
/* zero the digit bignum */
mp_zero(a);
/* make sure the radix is ok */
if (radix < 2 || radix > 64) {
return MP_VAL;
}
/* if the leading digit is a
* minus set the sign to negative.
*/
if (*str == '-') {
++str;
neg = MP_NEG;
} else {
neg = MP_ZPOS;
}
/* set the integer to the default of zero */
mp_zero (a);
/* process each digit of the string */
while (*str) {
/* if the radix < 36 the conversion is case insensitive
* this allows numbers like 1AB and 1ab to represent the same value
* [e.g. in hex]
*/
ch = (char) ((radix < 36) ? toupper (*str) : *str);
for (y = 0; y < 64; y++) {
if (ch == mp_s_rmap[y]) {
break;
}
}
/* if the char was found in the map
* and is less than the given radix add it
* to the number, otherwise exit the loop.
*/
if (y < radix) {
if ((res = mp_mul_d (a, (mp_digit) radix, a)) != MP_OKAY) {
return res;
}
if ((res = mp_add_d (a, (mp_digit) y, a)) != MP_OKAY) {
return res;
}
} else {
break;
}
++str;
}
/* set the sign only if a != 0 */
if (mp_iszero(a) != 1) {
a->sign = neg;
}
return MP_OKAY;
}
#endif
/* $Source: /cvs/libtom/libtommath/bn_mp_read_radix.c,v $ */
/* $Revision: 1.4 $ */
/* $Date: 2006/03/31 14:18:44 $ */
|