blob: 456a387a3f3b86fc1a1fcb1810ba447f5f832aa3 (
plain)
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
|
#include "tommath_private.h"
#ifdef BN_MP_READ_RADIX_C
/* LibTomMath, multiple-precision integer library -- Tom St Denis */
/* SPDX-License-Identifier: Unlicense */
#define MP_TOUPPER(c) ((((c) >= 'a') && ((c) <= 'z')) ? (((c) + 'A') - 'a') : (c))
/* read a string [ASCII] in a given radix */
mp_err mp_read_radix(mp_int *a, const char *str, int radix)
{
mp_err err;
int y;
mp_sign neg;
unsigned pos;
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 != '\0') {
/* 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 = (radix <= 36) ? (char)MP_TOUPPER((int)*str) : *str;
pos = (unsigned)(ch - '(');
if (MP_RMAP_REVERSE_SIZE < pos) {
break;
}
y = (int)s_mp_rmap_reverse[pos];
/* 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 == 0xff) || (y >= radix)) {
break;
}
if ((err = mp_mul_d(a, (mp_digit)radix, a)) != MP_OKAY) {
return err;
}
if ((err = mp_add_d(a, (mp_digit)y, a)) != MP_OKAY) {
return err;
}
++str;
}
/* if an illegal character was found, fail. */
if (!((*str == '\0') || (*str == '\r') || (*str == '\n'))) {
mp_zero(a);
return MP_VAL;
}
/* set the sign only if a != 0 */
if (!MP_IS_ZERO(a)) {
a->sign = neg;
}
return MP_OKAY;
}
#endif
|
