gcc/gmp/mpf/fits_u.h

/* mpf_fits_u*_p -- test whether an mpf fits a C unsigned type.

Copyright 2001, 2002 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 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 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 Lesser General Public
License for more details.

You should have received a copy of the GNU Lesser General Public License
along with the GNU MP Library.  If not, see http://www.gnu.org/licenses/.  */

#include "gmp.h"
#include "gmp-impl.h"


/* Notice this is equivalent to mpz_set_f + mpz_fits_u*_p.  */

int
FUNCTION (mpf_srcptr f)
{
  mp_size_t  fn;
  mp_srcptr  fp;
  mp_exp_t   exp;
  mp_limb_t  fl;

  fn = SIZ(f);
  if (fn <= 0)
    return fn == 0;  /* zero fits, negatives don't */

  exp = EXP(f);
  if (exp < 1)
    return 1;  /* 0 < f < 1 truncates to zero, so fits */

  fp = PTR(f);

  if (exp == 1)
    {
      fl = fp[fn-1];
    }
#if GMP_NAIL_BITS != 0
  else if (exp == 2 && MAXIMUM > GMP_NUMB_MAX)
    {
      fl = fp[fn-1];
      if ((fl >> GMP_NAIL_BITS) != 0)
	return 0;
      fl = (fl << GMP_NUMB_BITS);
      if (fn >= 2)
        fl |= fp[fn-2];
    }
#endif
  else
    return 0;

  return fl <= MAXIMUM;
}