/* Exercise the lc2exp random functions.

Copyright 2002 Free Software Foundation, Inc.

This file is part of the GNU MP Library.

The GNU MP Library is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or (at your
option) any later version.

The GNU MP Library 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 Lesser General Public
License for more details.

You should have received a copy of the GNU Lesser General Public License
along with the GNU MP Library; see the file COPYING.LIB.  If not, write to
the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
MA 02111-1307, USA. */

#include <stdio.h>
#include <stdlib.h>
#include "gmp.h"
#include "gmp-impl.h"
#include "tests.h"


/* a=0 and c=0 produces zero results always. */
void
check_zero (unsigned long m2exp)
{
  gmp_randstate_t  r;
  mpz_t            a;
  unsigned long    c;
  int              i;

  mpz_init_set_ui (a, 0L);
  c = 0L;

  gmp_randinit_lc_2exp (r, a, c, m2exp);
  gmp_randseed_ui (r, 0L);

  for (i = 0; i < 5; i++)
    {
      mpz_urandomb (a, r, 123L);
      if (mpz_sgn (a) != 0)
        {
          printf ("check_zero m2exp=%lu: didn't get zero\n", m2exp);
          gmp_printf ("  rand=%#Zx\n", a);
          abort ();
        }
    }

  mpz_clear (a);
  gmp_randclear (r);
}

/* negative a */
void
check_nega (void)
{
  gmp_randstate_t  r;
  mpz_t            a;
  unsigned long    c, m2exp;
  int              i;

  mpz_init (a);
  mpz_setbit (a, 1000L);
  mpz_neg (a, a);
  c = 0L;
  m2exp = 45L;

  gmp_randinit_lc_2exp (r, a, c, m2exp);
  gmp_randseed_ui (r, 0L);

  for (i = 0; i < 5; i++)
    {
      mpz_urandomb (a, r, 123L);
      if (mpz_sgn (a) != 0)
        printf ("check_nega m2exp=%lu: didn't get zero\n", m2exp);
    }

  mpz_clear (a);
  gmp_randclear (r);
}

void
check_bigc (void)
{
  gmp_randstate_t  r;
  mpz_t            a;
  unsigned long    c, m2exp, bits;
  int              i;

  mpz_init_set_ui (a, 0L);
  c = ULONG_MAX;
  m2exp = 8;

  gmp_randinit_lc_2exp (r, a, c, m2exp);
  gmp_randseed_ui (r, 0L);

  for (i = 0; i < 20; i++)
    {
      bits = 123L;
      mpz_urandomb (a, r, bits);
      if (mpz_sgn (a) < 0 || mpz_sizeinbase (a, 2) > bits)
        {
          printf     ("check_bigc: mpz_urandomb out of range\n");
          printf     ("   m2exp=%lu\n", m2exp);
          gmp_printf ("   rand=%#ZX\n", a);
          gmp_printf ("   sizeinbase2=%u\n", mpz_sizeinbase (a, 2));
        }
    }

  mpz_clear (a);
  gmp_randclear (r);
}

/* In the past c bigger than m2exp bits was not truncated, and could end up
   producing extra bits from _gmp_rand and consequently into mpz_urandomb.
   The following tries a=0 c=ULONG_MAX m2exp=2 expecting to see mpz_urandomb
   ask for 1 bit give a value 1 every time.  */
void
check_bigc1 (void)
{
  gmp_randstate_t  r;
  mpz_t            a;
  unsigned long    c, m2exp;
  int              i;

  mpz_init_set_ui (a, 0L);
  c = ULONG_MAX;
  m2exp = 2;

  gmp_randinit_lc_2exp (r, a, c, m2exp);
  gmp_randseed_ui (r, 0L);

  for (i = 0; i < 20; i++)
    {
      mpz_urandomb (a, r, 1L);
      if (mpz_cmp_ui (a, 1L) != 0)
        {
          printf     ("check_bigc1: mpz_urandomb didn't give 1\n");
          printf     ("   m2exp=%lu\n", m2exp);
          gmp_printf ("   got rand=%#ZX\n", a);
          abort ();
        }
    }

  mpz_clear (a);
  gmp_randclear (r);
}

/* Checks parameters which triggered an assertion failure in the past.
   Happened when limbs(a)+limbs(c) < bits_to_limbs(m2exp).  */
void
check_bigm (void)
{
  gmp_randstate_t rstate;
  mpz_t a;

  mpz_init_set_ui (a, 5L);
  gmp_randinit_lc_2exp (rstate, a, 1L, 384L);

  mpz_urandomb (a, rstate, 20L);

  gmp_randclear (rstate);
  mpz_clear (a);
}

/* Checks for seeds bigger than the modulus.  */
void
check_bigs (void)
{
  gmp_randstate_t rstate;
  mpz_t sd, a;
  int i;

  mpz_init (sd);
  mpz_setbit (sd, 300L);
  mpz_sub_ui (sd, sd, 1L);
  mpz_clrbit (sd, 13L);
  mpz_init_set_ui (a, 123456789L);

  gmp_randinit_lc_2exp (rstate, a, 5L, 64L);

  for (i = 0; i < 20; i++)
    {
      mpz_neg (sd, sd);
      gmp_randseed (rstate, sd);
      mpz_mul_ui (sd, sd, 7L);

      mpz_urandomb (a, rstate, 80L);
    }

  gmp_randclear (rstate);
  mpz_clear (a);
  mpz_clear (sd);
}

int
main (void)
{
  tests_start ();

  check_zero (2L);
  check_zero (7L);
  check_zero (32L);
  check_zero (64L);
  check_zero (1000L);

  check_nega ();
  check_bigc ();
  check_bigc1 ();

  check_bigm ();
  check_bigs ();

  tests_end ();
  exit (0);
}
