67 lines
1.3 KiB
C
67 lines
1.3 KiB
C
#include "tommath_private.h"
|
|
#ifdef MP_FREAD_C
|
|
/* LibTomMath, multiple-precision integer library -- Tom St Denis */
|
|
/* SPDX-License-Identifier: Unlicense */
|
|
|
|
#ifndef MP_NO_FILE
|
|
/* read a bigint from a file stream in ASCII */
|
|
mp_err mp_fread(mp_int *a, int radix, FILE *stream)
|
|
{
|
|
mp_err err;
|
|
mp_sign sign = MP_ZPOS;
|
|
int ch;
|
|
|
|
/* make sure the radix is ok */
|
|
if ((radix < 2) || (radix > 64)) {
|
|
return MP_VAL;
|
|
}
|
|
|
|
/* if first digit is - then set negative */
|
|
ch = fgetc(stream);
|
|
if (ch == (int)'-') {
|
|
sign = MP_NEG;
|
|
ch = fgetc(stream);
|
|
}
|
|
|
|
/* no digits, return error */
|
|
if (ch == EOF) {
|
|
return MP_ERR;
|
|
}
|
|
|
|
/* clear a */
|
|
mp_zero(a);
|
|
|
|
do {
|
|
uint8_t y;
|
|
unsigned pos;
|
|
ch = (radix <= 36) ? MP_TOUPPER(ch) : ch;
|
|
pos = (unsigned)(ch - (int)'+');
|
|
if (MP_RADIX_MAP_REVERSE_SIZE <= pos) {
|
|
break;
|
|
}
|
|
|
|
y = s_mp_radix_map_reverse[pos];
|
|
|
|
if (y >= radix) {
|
|
break;
|
|
}
|
|
|
|
/* shift up and add */
|
|
if ((err = mp_mul_d(a, (mp_digit)radix, a)) != MP_OKAY) {
|
|
return err;
|
|
}
|
|
if ((err = mp_add_d(a, y, a)) != MP_OKAY) {
|
|
return err;
|
|
}
|
|
} while ((ch = fgetc(stream)) != EOF);
|
|
|
|
if (!mp_iszero(a)) {
|
|
a->sign = sign;
|
|
}
|
|
|
|
return MP_OKAY;
|
|
}
|
|
#endif
|
|
|
|
#endif
|