/* mpfr_get_uj -- convert a MPFR number to a huge machine unsigned integer

Copyright 2004, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Free Software Foundation, Inc.
Contributed by the AriC and Caramel 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. */

#ifdef HAVE_CONFIG_H
# include "config.h"       /* for a build within gmp */
#endif

#include "mpfr-intmax.h"
#include "mpfr-impl.h"

#ifdef _MPFR_H_HAVE_INTMAX_T

uintmax_t
mpfr_get_uj (mpfr_srcptr f, mpfr_rnd_t rnd)
{
  uintmax_t r;
  mpfr_prec_t prec;
  mpfr_t x;

  if (MPFR_UNLIKELY (!mpfr_fits_uintmax_p (f, rnd)))
    {
      MPFR_SET_ERANGE ();
      return MPFR_IS_NAN (f) || MPFR_IS_NEG (f) ?
        (uintmax_t) 0 : MPFR_UINTMAX_MAX;
    }

  if (MPFR_IS_ZERO (f))
    return (uintmax_t) 0;

  /* determine the precision of uintmax_t */
  for (r = MPFR_UINTMAX_MAX, prec = 0; r != 0; r /= 2, prec++)
    { }

  /* Now, r = 0. */

  mpfr_init2 (x, prec);
  mpfr_rint (x, f, rnd);
  MPFR_ASSERTN (MPFR_IS_FP (x));

  if (MPFR_NOTZERO (x))
    {
      mp_limb_t *xp;
      int sh, n;  /* An int should be sufficient in this context. */

      MPFR_ASSERTN (MPFR_IS_POS (x));
      xp = MPFR_MANT (x);
      sh = MPFR_GET_EXP (x);
      MPFR_ASSERTN ((mpfr_prec_t) sh <= prec);
      for (n = MPFR_LIMB_SIZE(x) - 1; n >= 0; n--)
        {
          sh -= GMP_NUMB_BITS;
          r += (sh >= 0
                ? (uintmax_t) xp[n] << sh
                : (uintmax_t) xp[n] >> (- sh));
        }
    }

  mpfr_clear (x);

  return r;
}

#endif
