/* mpf_trunc -- truncate an mpf to an integer.

Copyright 2001 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 "gmp.h"

#include "gmp-impl.h"

/* Notice the use of prec+1 ensures mpf_trunc is equivalent to mpf_set if u

   is already an integer.  */

void

mpf_trunc (mpf_ptr r, mpf_srcptr u)

{

  mp_ptr     rp;

  mp_srcptr  up;

  mp_size_t  size, asize, prec;

  mp_exp_t   exp;

  exp = EXP(u);

  size = SIZ(u);

  if (size == 0 || exp <= 0)

    {

      /* u is only a fraction */

      SIZ(r) = 0;

      EXP(r) = 0;

      return;

    }

  up = PTR(u);

  EXP(r) = exp;

  asize = ABS (size);

  up += asize;

  /* skip fraction part of u */

  asize = MIN (asize, exp);

  /* don't lose precision in the copy */

  prec = PREC(r) + 1;

  /* skip excess over target precision */

  asize = MIN (asize, prec);

  up -= asize;

  rp = PTR(r);

  SIZ(r) = (size >= 0 ? asize : -asize);

  if (rp != up)

    MPN_COPY_INCR (rp, up, asize);

}