86 lines
2.0 KiB
C
86 lines
2.0 KiB
C
#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://libtom.org
|
|
*/
|
|
|
|
/* 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 ((int)*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
|
|
|
|
/* $Source$ */
|
|
/* $Revision$ */
|
|
/* $Date$ */
|