libtommath/bn_mp_prime_is_divisible.c
2010-07-15 17:25:56 +02:00

51 lines
1.2 KiB
C

#include <tommath.h>
#ifdef BN_MP_PRIME_IS_DIVISIBLE_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@iahu.ca, http://math.libtomcrypt.org
*/
/* determines if an integers is divisible by one
* of the first PRIME_SIZE primes or not
*
* sets result to 0 if not, 1 if yes
*/
int mp_prime_is_divisible (mp_int * a, int *result)
{
int err, ix;
mp_digit res;
/* default to not */
*result = MP_NO;
for (ix = 0; ix < 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 == 0) {
*result = MP_YES;
return MP_OKAY;
}
}
return MP_OKAY;
}
#endif
/* $Source$ */
/* $Revision$ */
/* $Date$ */