/* mpq_set_d(mpq_t q, double d) -- Set q to d without rounding.

Copyright 2000, 2002, 2003, 2012, 2014 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 either:

  * 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.

or

  * the GNU General Public License as published by the Free Software

    Foundation; either version 2 of the License, or (at your option) any

    later version.

or both in parallel, as here.

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 General Public License

for more details.

You should have received copies of the GNU General Public License and the

GNU Lesser General Public License along with the GNU MP Library.  If not,

see https://www.gnu.org/licenses/.  */

#include "config.h"

#if HAVE_FLOAT_H

#include <float.h>  /* for DBL_MAX */

#endif

#include "gmp.h"

#include "gmp-impl.h"

#include "longlong.h"

#if LIMBS_PER_DOUBLE > 4

  choke me

#endif

void

mpq_set_d (mpq_ptr dest, double d)

{

  int negative;

  mp_exp_t exp;

  mp_limb_t tp[LIMBS_PER_DOUBLE];

  mp_ptr np, dp;

  mp_size_t nn, dn;

  int c;

  DOUBLE_NAN_INF_ACTION (d,

                         __gmp_invalid_operation (),

                         __gmp_invalid_operation ());

  negative = d < 0;

  d = ABS (d);

  exp = __gmp_extract_double (tp, d);

  /* There are two main version of the conversion.  The `then' arm handles

     numbers with a fractional part, while the `else' arm handles integers.  */

#if LIMBS_PER_DOUBLE == 4

  if (exp <= 1 || (exp == 2 && (tp[0] | tp[1]) != 0))

#endif

#if LIMBS_PER_DOUBLE == 3

  if (exp <= 1 || (exp == 2 && tp[0] != 0))

#endif

#if LIMBS_PER_DOUBLE == 2

  if (exp <= 1)

#endif

    {

      if (d == 0.0)

	{

	  SIZ(NUM(dest)) = 0;

	  SIZ(DEN(dest)) = 1;

	  PTR(DEN(dest))[0] = 1;

	  return;

	}

#if LIMBS_PER_DOUBLE == 4

      np = MPZ_NEWALLOC (NUM(dest), 4);

      if ((tp[0] | tp[1] | tp[2]) == 0)

	np[0] = tp[3], nn = 1;

      else if ((tp[0] | tp[1]) == 0)

	np[1] = tp[3], np[0] = tp[2], nn = 2;

      else if (tp[0] == 0)

	np[2] = tp[3], np[1] = tp[2], np[0] = tp[1], nn = 3;

      else

	np[3] = tp[3], np[2] = tp[2], np[1] = tp[1], np[0] = tp[0], nn = 4;

#endif

#if LIMBS_PER_DOUBLE == 3

      np = MPZ_NEWALLOC (NUM(dest), 3);

      if ((tp[0] | tp[1]) == 0)

	np[0] = tp[2], nn = 1;

      else if (tp[0] == 0)

	np[1] = tp[2], np[0] = tp[1], nn = 2;

      else

	np[2] = tp[2], np[1] = tp[1], np[0] = tp[0], nn = 3;

#endif

#if LIMBS_PER_DOUBLE == 2

      np = MPZ_NEWALLOC (NUM(dest), 2);

      if (tp[0] == 0)

	np[0] = tp[1], nn = 1;

      else

	np[1] = tp[1], np[0] = tp[0], nn = 2;

#endif

      dn = nn + 1 - exp;

      ASSERT (dn > 0); /* -exp >= -1; nn >= 1*/

      dp = MPZ_NEWALLOC (DEN(dest), dn);

      MPN_ZERO (dp, dn - 1);

      dp[dn - 1] = 1;

      count_trailing_zeros (c, np[0] | dp[0]);

      if (c != 0)

	{

	  mpn_rshift (np, np, nn, c);

	  nn -= np[nn - 1] == 0;

	  --dn;

	  dp[dn - 1] = CNST_LIMB(1) << (GMP_LIMB_BITS - c);

	}

      SIZ(DEN(dest)) = dn;

    }

  else

    {

      nn = exp;

      np = MPZ_NEWALLOC (NUM(dest), nn);

      switch (nn)

        {

	default:

	  MPN_ZERO (np, nn - LIMBS_PER_DOUBLE);

	  np += nn - LIMBS_PER_DOUBLE;

	  /* fall through */

#if LIMBS_PER_DOUBLE == 2

	case 2:

	  np[1] = tp[1], np[0] = tp[0];

	  break;

#endif

#if LIMBS_PER_DOUBLE == 3

	case 3:

	  np[2] = tp[2], np[1] = tp[1], np[0] = tp[0];

	  break;

	case 2:

	  np[1] = tp[2], np[0] = tp[1];

	  break;

#endif

#if LIMBS_PER_DOUBLE == 4

	case 4:

	  np[3] = tp[3], np[2] = tp[2], np[1] = tp[1], np[0] = tp[0];

	  break;

	case 3:

	  np[2] = tp[3], np[1] = tp[2], np[0] = tp[1];

	  break;

	case 2:

	  np[1] = tp[3], np[0] = tp[2];

	  break;

#endif

	}

      *PTR(DEN(dest)) = 1;

      SIZ(DEN(dest)) = 1;

    }

  SIZ(NUM(dest)) = negative ? -nn : nn;

}