/**
 * expmodtest.c
 *   A simple test of the expmod function in SamR's simple math library.
 *
 *   Copyright (c) 2022 Samuel A. Rebelsky.  All rights reserved.
 *
 *   This file is part of SRMath, SamR's simple math library.
 *
 *   SRMath is free software: you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation, either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   SRMath is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with SRMath.  If not, see <http://www.gnu.org/licenses/>.
 */


// +-------+-----------------------------------------------------------
// | Notes |
// +-------+


// +---------+---------------------------------------------------------
// | Headers |
// +---------+

#include "srmath.h"
#include "srtest.h"
#include <limits.h>
#include <stdlib.h>


// +--------+----------------------------------------------------------
// | Macros |
// +--------+


// +---------+-------------------------------------------------------
// | Helpers |
// +---------+

long
dumbmod (long x, long n, long m)
{
  long result = 1;
  for (long i = 0; i < n; i++) 
    {
      result = (result * x) % m;
    }
  return result;
} // dumbmod

void
random_test ()
{
  long x = random () % INT_MAX;
  long n = random () % 100;
  long m = random ();
  SR_CHECK_LONG (stderr, expmod (x, n, m), dumbmod (x, n, m));
}



// +------+------------------------------------------------------------
// | Main |
// +------+

int
main (int argc, char *argv[])
{
  sr_reset();

  // Easy ones that we can write by hand
  SR_CHECK_LONG (stderr, expmod (2, 3, 4), 0);
  SR_CHECK_LONG (stderr, expmod (5, 6, 7), 1);
  SR_CHECK_LONG (stderr, expmod (3, 3, 2), 1);
  SR_CHECK_LONG (stderr, expmod (3, 2, 1), 0);
  SR_CHECK_LONG (stderr, expmod (5, 3, 10), 5);

  // Harder ones
  SR_CHECK_LONG (stderr, expmod (17, 93, 1033), dumbmod (17, 93, 1033));

  // Random ones
  random_test ();
  random_test ();
  random_test ();
  random_test ();
  random_test ();

  if (sr_get_errors() != 0)
    {
      sr_report (stderr);
      return 1;
    } // if (sr_errors != 0)

  // And we're done
  return 0;
} // main