80 lines
1.9 KiB
C
80 lines
1.9 KiB
C
#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_s_rmap_reverse_sz < pos) {
|
|
break;
|
|
}
|
|
y = (int)mp_s_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
|