/* Test file for mpfr_get_d

Copyright 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
Contributed by the Arenaire and Cacao projects, INRIA.

This file is part of the GNU MPFR Library.

The GNU 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 3 of the License, or (at your
option) any later version.

The GNU 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 GNU MPFR Library; see the file COPYING.LESSER.  If not, see
http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */

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

#include "mpfr-test.h"

static int
check_denorms (void)
{
  mpfr_rnd_t rnd_mode;
  mpfr_t x;
  double d, d2, dd, f;
  int fail = 0, k, n;

  mpfr_init2 (x, GMP_NUMB_BITS);

  rnd_mode = MPFR_RNDN;
  for (k = -17; k <= 17; k += 2)
    {
      d = (double) k * DBL_MIN; /* k * 2^(-1022) */
      f = 1.0;
      mpfr_set_si (x, k, MPFR_RNDN);
      mpfr_div_2exp (x, x, 1022, MPFR_RNDN); /* k * 2^(-1022) */
      for (n = 0; n <= 58; n++)
        {
          d2 = d * f;
          dd = mpfr_get_d (x, rnd_mode);
          if (d2 != dd) /* should be k * 2^(-1022-n) for n < 53 */
            {
              printf ("Wrong result for %d * 2^(%d), rnd_mode %d\n",
                      k, -1022-n, rnd_mode);
              printf ("got %.20e instead of %.20e\n", dd, d2);
              fail = 1;
            }
          f *= 0.5;
          mpfr_div_2exp (x, x, 1, MPFR_RNDN);
        }
    }

  mpfr_set_str_binary (x, "1e-1074");
  dd = mpfr_get_d (x, MPFR_RNDA);
  d2 = DBL_MIN; /* 2^(-1022) */
  for (k = 0; k < 52; k++)
    d2 *= 0.5;  /* 2^(-1074) */
  /* we first check that d2 is not zero (it could happen on a platform with
     no subnormals) */
  if (d2 != 0.0 && dd != d2)
    {
      printf ("Error for x=1e-1074, RNDA\n");
      exit (1);
    }

  mpfr_set_str_binary (x, "1e-1075");
  dd = mpfr_get_d (x, MPFR_RNDA);
  if (d2 != 0.0 && dd != d2)
    {
      printf ("Error for x=1e-1075, RNDA\n");
      printf ("expected %.16e\n", d2);
      printf ("got      %.16e\n", dd);
      exit (1);
    }

  mpfr_clear (x);
  return fail;
}

static void
check_inf_nan (void)
{
  /* only if nans and infs are available */
#if _GMP_IEEE_FLOATS
  mpfr_t  x;
  double  d;

  mpfr_init2 (x, 123);

  mpfr_set_inf (x, 1);
  d = mpfr_get_d (x, MPFR_RNDZ);
  ASSERT_ALWAYS (d > 0);
  ASSERT_ALWAYS (DOUBLE_ISINF (d));

  mpfr_set_inf (x, -1);
  d = mpfr_get_d (x, MPFR_RNDZ);
  ASSERT_ALWAYS (d < 0);
  ASSERT_ALWAYS (DOUBLE_ISINF (d));

  mpfr_set_nan (x);
  d = mpfr_get_d (x, MPFR_RNDZ);
  ASSERT_ALWAYS (DOUBLE_ISNAN (d));

  mpfr_clear (x);
#endif
}

static void
check_max (void)
{
  double d, e;
  mpfr_t u;

  d = 1.0;
  while (d < (DBL_MAX / 2.0))
    d += d;
  mpfr_init (u);
  if (mpfr_set_d (u, d, MPFR_RNDN) == 0)
    {
      /* If setting is exact */
      e = (mpfr_get_d1) (u);
      if (e != d)
        {
          printf ("get_d(set_d)(1): %1.20e != %1.20e\n", d, e);
          exit (1);
        }
    }

  mpfr_set_str_binary (u, "-1E1024");
  d = mpfr_get_d (u, MPFR_RNDZ);
  MPFR_ASSERTN(d == -DBL_MAX);
  d = mpfr_get_d (u, MPFR_RNDU);
  MPFR_ASSERTN(d == -DBL_MAX);
  d = mpfr_get_d (u, MPFR_RNDN);
  MPFR_ASSERTN(DOUBLE_ISINF(d) && d < 0.0);
  d = mpfr_get_d (u, MPFR_RNDD);
  MPFR_ASSERTN(DOUBLE_ISINF(d) && d < 0.0);

  mpfr_set_str_binary (u, "1E1024");
  d = mpfr_get_d (u, MPFR_RNDZ);
  MPFR_ASSERTN(d == DBL_MAX);
  d = mpfr_get_d (u, MPFR_RNDD);
  MPFR_ASSERTN(d == DBL_MAX);
  d = mpfr_get_d (u, MPFR_RNDN);
  MPFR_ASSERTN(DOUBLE_ISINF(d) && d > 0.0);
  d = mpfr_get_d (u, MPFR_RNDU);
  MPFR_ASSERTN(DOUBLE_ISINF(d) && d > 0.0);

  mpfr_clear (u);
}

static void
check_min(void)
{
  double d, e;
  mpfr_t u;

  d = 1.0; while (d > (DBL_MIN * 2.0)) d /= 2.0;
  mpfr_init(u);
  if (mpfr_set_d(u, d, MPFR_RNDN) == 0)
    {
      /* If setting is exact */
      e = mpfr_get_d1(u);
      if (e != d)
        {
          printf("get_d(set_d)(2): %1.20e != %1.20e\n", d, e);
          exit(1);
        }
    }
  mpfr_clear(u);
}

int
main (void)
{
  tests_start_mpfr ();
  mpfr_test_init ();

#ifndef MPFR_DOUBLE_SPEC
  printf ("Warning! The MPFR_DOUBLE_SPEC macro is not defined. This means\n"
          "that you do not have a conforming C implementation and problems\n"
          "may occur with conversions between MPFR numbers and standard\n"
          "floating-point types. Please contact the MPFR team.\n");
#elif MPFR_DOUBLE_SPEC == 0
  /*
  printf ("The type 'double' of your C implementation does not seem to\n"
          "correspond to the IEEE-754 double precision. Though code has\n"
          "been written to support such implementations, tests have been\n"
          "done only on IEEE-754 double-precision implementations and\n"
          "conversions between MPFR numbers and standard floating-point\n"
          "types may be inaccurate. You may wish to contact the MPFR team\n"
          "for further testing.\n");
  */
  printf ("The type 'double' of your C implementation does not seem to\n"
          "correspond to the IEEE-754 double precision. Such particular\n"
          "implementations are not supported yet, and conversions between\n"
          "MPFR numbers and standard floating-point types may be very\n"
          "inaccurate.\n");
  printf ("FLT_RADIX    = %ld\n", (long) FLT_RADIX);
  printf ("DBL_MANT_DIG = %ld\n", (long) DBL_MANT_DIG);
  printf ("DBL_MIN_EXP  = %ld\n", (long) DBL_MIN_EXP);
  printf ("DBL_MAX_EXP  = %ld\n", (long) DBL_MAX_EXP);
#endif

  if (check_denorms ())
    exit (1);

  check_inf_nan ();
  check_min();
  check_max();

  tests_end_mpfr ();
  return 0;
}
