/* Test file for mpfr_nextabove, mpfr_nextbelow, mpfr_nexttoward.

Copyright 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
Contributed by the Arenaire and Cacao projects, INRIA.

This file is part of the MPFR Library.

The MPFR 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 MPFR 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 MPFR Library; see the file COPYING.LIB.  If not, write to
the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
MA 02110-1301, USA. */

#include <stdio.h>
#include <stdlib.h>

#include "mpfr-test.h"

/* Generic tests for mpfr_nextabove and mpfr_nextbelow */
static void
generic_abovebelow (void)
{
  int i;

  for (i = 0; i < 20000; i++)
    {
      mpfr_t x, y, z, t;
      mp_prec_t prec;
      int neg, below;

      prec = (randlimb () % 300) + MPFR_PREC_MIN;
      mpfr_inits2 (prec, x, y, z, (void *) 0);
      mpfr_init2 (t, 3);

      /* special tests (executed once is enough) */
      if (i == 0)
        {
          mpfr_set_nan (x);
          mpfr_nextabove (x);
          MPFR_ASSERTN(mpfr_nan_p (x));
          mpfr_nextbelow (x);
          MPFR_ASSERTN(mpfr_nan_p (x));
          mpfr_nexttoward (x, y);
          MPFR_ASSERTN(mpfr_nan_p (x));
          mpfr_set_ui (y, 1, GMP_RNDN);
          mpfr_nexttoward (y, x);
          MPFR_ASSERTN(mpfr_nan_p (y));
          mpfr_set_ui (x, 1, GMP_RNDN);
          mpfr_set_ui (y, 1, GMP_RNDN);
          mpfr_nexttoward (x, y);
          MPFR_ASSERTN(mpfr_cmp_ui (x, 1) == 0);
        }

      do
        mpfr_random (x);
      while (mpfr_cmp_ui (x, 0) == 0);
      neg = randlimb () & 1;
      if (neg)
        mpfr_neg (x, x, GMP_RNDN);
      mpfr_set (y, x, GMP_RNDN);
      below = randlimb () & 1;
      if (below)
        mpfr_nextbelow (y);
      else
        mpfr_nextabove (y);
      mpfr_set_si (t, below ? -5 : 5, GMP_RNDN);
      mpfr_mul_2si (t, t, (mpfr_get_exp) (x) - prec - 3, GMP_RNDN);
      /* t = (1/2 + 1/8) ulp(x) */
      mpfr_add (z, x, t, GMP_RNDN);
      if (!mpfr_number_p (y) || mpfr_cmp (y, z) != 0)
        {
          printf ("Error in mpfr_next%s for\n",
                  below ? "below" : "above");
          mpfr_out_str (stdout, 2, 0, x, GMP_RNDN);
          printf (", got\n");
          mpfr_out_str (stdout, 2, 0, y, GMP_RNDN);
          printf (" instead of\n");
          mpfr_out_str (stdout, 2, 0, z, GMP_RNDN);
          printf ("\n");
          exit (1);
        }
      mpfr_clears (x, y, z, t, (void *) 0);
    }
}

static void
inverse_test (void)
{
  static const char *tests[] = { "0", "1", "2", "3.1", "Inf" };
  int i, neg, below;
  mp_prec_t prec;

  for (i = 0; i < (int) (sizeof(tests) / sizeof(tests[0])); i++)
    for (neg = 0; neg <= 1; neg++)
      for (below = 0; below <= 1; below++)
        for (prec = MPFR_PREC_MIN; prec < 200; prec += 3)
          {
            mpfr_t x, y;
            int sign;

            mpfr_inits2 (prec, x, y, (void *) 0);
            mpfr_set_str (x, tests[i], 10, GMP_RNDN);
            if (neg)
              mpfr_neg (x, x, GMP_RNDN);
            mpfr_set (y, x, GMP_RNDN);
            if (below)
              mpfr_nextbelow (y);
            else
              mpfr_nextabove (y);
            sign = MPFR_SIGN (y);
            if (!(neg == below && mpfr_inf_p (x)))  /* then x = y */
              {
                if (mpfr_cmp (x, y) == 0)
                  {
                    printf ("Error in inverse_test for %s, neg = %d,"
                            " below = %d, prec = %d: x = y", tests[i],
                            neg, below, (int) prec);
                    printf ("\nx = ");
                    mpfr_out_str (stdout, 2, 0, x, GMP_RNDN);
                    printf ("\ny = ");
                    mpfr_out_str (stdout, 2, 0, y, GMP_RNDN);
                    printf ("\n");
                    exit (1);
                 }
                mpfr_nexttoward (y, x);
                if (mpfr_cmp_ui (y, 0) == 0 && MPFR_SIGN (y) != sign)
                  {
                    printf ("Sign error in inverse_test for %s, neg = %d,"
                            " below = %d, prec = %d\n", tests[i], neg,
                            below, (int) prec);
                    mpfr_out_str (stdout, 2, 0, y, GMP_RNDN);
                    printf ("\n");
                    exit (1);
                  }
              }
            if (mpfr_cmp (x, y) != 0)
              {
                printf ("Error in inverse_test for %s, neg = %d, below = %d,"
                        " prec = %d", tests[i], neg, below, (int) prec);
                printf ("\nx = ");
                mpfr_out_str (stdout, 2, 0, x, GMP_RNDN);
                printf ("\ny = ");
                mpfr_out_str (stdout, 2, 0, y, GMP_RNDN);
                printf ("\n");
                exit (1);
              }
            mpfr_clears (x, y, (void *) 0);
          }
}

int
main (void)
{
  tests_start_mpfr ();
  generic_abovebelow ();
  inverse_test ();
  tests_end_mpfr ();
  return 0;
}