libtommath/bn_mp_prime_is_divisible.c
2019-05-07 09:49:26 +02:00

35 lines
789 B
C

#include "tommath_private.h"
#ifdef BN_MP_PRIME_IS_DIVISIBLE_C
/* LibTomMath, multiple-precision integer library -- Tom St Denis */
/* SPDX-License-Identifier: Unlicense */
/* determines if an integers is divisible by one
* of the first MP_PRIME_SIZE primes or not
*
* sets result to 0 if not, 1 if yes
*/
int mp_prime_is_divisible(const mp_int *a, int *result)
{
int err, ix;
mp_digit res;
/* default to not */
*result = MP_NO;
for (ix = 0; ix < MP_PRIME_SIZE; ix++) {
/* what is a mod LBL_prime_tab[ix] */
if ((err = mp_mod_d(a, ltm_prime_tab[ix], &res)) != MP_OKAY) {
return err;
}
/* is the residue zero? */
if (res == 0u) {
*result = MP_YES;
return MP_OKAY;
}
}
return MP_OKAY;
}
#endif