view libtommath/bn_mp_prime_is_divisible.c @ 412:47bcc3536bd5

merge of '691c56da3db2685f58ea53540a73c1b79e7df9cd' and 'e0efd546c3cdb2828971e41af2afe43e850c641d'
author Matt Johnston <matt@ucc.asn.au>
date Sun, 04 Feb 2007 10:44:12 +0000
parents 5ff8218bcee9
children 60fc6476e044
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#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, [email protected], http://math.libtomcrypt.com
 */

/* 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: /cvs/libtom/libtommath/bn_mp_prime_is_divisible.c,v $ */
/* $Revision: 1.3 $ */
/* $Date: 2006/03/31 14:18:44 $ */