/* Test mpz_powm_ui, mpz_mul, mpz_mod.

Copyright 1991, 1993, 1994, 1996, 1997, 2000-2002, 2013 Free Software

Foundation, Inc.

This file is part of the GNU MP Library test suite.

The GNU MP Library test suite 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.

The GNU MP Library test suite 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

the GNU MP Library test suite.  If not, see https://www.gnu.org/licenses/.  */

#include <stdio.h>

#include <stdlib.h>

#include "gmp.h"

#include "gmp-impl.h"

#include "tests.h"

int

main (int argc, char **argv)

{

  mpz_t base, exp, mod;

  mpz_t r1, r2, base2;

  mp_size_t base_size, exp_size, mod_size;

  unsigned long int exp2;

  int i;

  int reps = 100;

  gmp_randstate_ptr rands;

  mpz_t bs;

  unsigned long bsi, size_range;

  tests_start ();

  rands = RANDS;

  TESTS_REPS (reps, argv, argc);

  mpz_inits (bs, base, exp, mod, r1, r2, base2, NULL);

  for (i = 0; i < reps; i++)

    {

      mpz_urandomb (bs, rands, 32);

      size_range = mpz_get_ui (bs) % 18 + 2;

      do  /* Loop until mathematically well-defined.  */

	{

	  mpz_urandomb (bs, rands, size_range);

	  base_size = mpz_get_ui (bs);

	  mpz_rrandomb (base, rands, base_size);

	  mpz_urandomb (bs, rands, 6L);

	  exp_size = mpz_get_ui (bs);

	  mpz_rrandomb (exp, rands, exp_size);

	  exp2 = mpz_getlimbn (exp, (mp_size_t) 0);

	}

      while (mpz_cmp_ui (base, 0) == 0 && exp2 == 0);

      do

        {

	  mpz_urandomb (bs, rands, size_range);

	  mod_size = mpz_get_ui (bs);

	  mpz_rrandomb (mod, rands, mod_size);

	}

      while (mpz_cmp_ui (mod, 0) == 0);

      mpz_urandomb (bs, rands, 2);

      bsi = mpz_get_ui (bs);

      if ((bsi & 1) != 0)

	mpz_neg (base, base);

      /* printf ("%ld %ld\n", SIZ (base), SIZ (mod)); */

#if 0

      putc ('\n', stderr);

      gmp_fprintf (stderr, "B = 0x%Zx\n", base);

      gmp_fprintf (stderr, "M = 0x%Zx\n", mod);

#endif

      exp2 = mpz_getlimbn (exp, (mp_size_t) 0);

      mpz_set_ui (r2, 1);

      mpz_set (base2, base);

      mpz_mod (r2, r2, mod);	/* needed when exp==0 and mod==1 */

      while (exp2 != 0)

	{

	  if (exp2 % 2 != 0)

	    {

	      mpz_mul (r2, r2, base2);

	      mpz_mod (r2, r2, mod);

	    }

	  mpz_mul (base2, base2, base2);

	  mpz_mod (base2, base2, mod);

	  exp2 = exp2 / 2;

	}

      exp2 = mpz_getlimbn (exp, (mp_size_t) 0);

      mpz_powm_ui (r1, base, exp2, mod);

      MPZ_CHECK_FORMAT (r1);

#if 0

      gmp_fprintf (stderr, "R   = 0x%Zx\n", r1);

      gmp_fprintf (stderr, "REF = 0x%Zx\n", r2);

#endif

      if (mpz_cmp (r1, r2) != 0)

	{

	  fprintf (stderr, "\ntest %d: Incorrect results for operands:\n", i);

	  gmp_fprintf (stderr, "B = 0x%Zx\n", base);

	  gmp_fprintf (stderr, "E = 0x%Zx\n", exp);

	  gmp_fprintf (stderr, "M = 0x%Zx\n", mod);

	  gmp_fprintf (stderr, "R   = 0x%Zx\n", r1);

	  gmp_fprintf (stderr, "REF = 0x%Zx\n", r2);

	  abort ();

	}

    }

  mpz_clears (bs, base, exp, mod, r1, r2, base2, NULL);

  tests_end ();

  exit (0);

}