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/* mpfr_get_ui -- convert a floating-point number to an unsigned long.
Copyright 2003-2004, 2006-2020 Free Software Foundation, Inc.
Contributed by the AriC and Caramba 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
https://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
#include "mpfr-impl.h"
unsigned long
mpfr_get_ui (mpfr_srcptr f, mpfr_rnd_t rnd)
{
mpfr_prec_t prec;
unsigned long s;
mpfr_t x;
mp_size_t n;
mpfr_exp_t exp;
MPFR_SAVE_EXPO_DECL (expo);
if (MPFR_UNLIKELY (!mpfr_fits_ulong_p (f, rnd)))
{
MPFR_SET_ERANGEFLAG ();
return MPFR_IS_NAN (f) || MPFR_IS_NEG (f) ?
(unsigned long) 0 : ULONG_MAX;
}
if (MPFR_IS_ZERO (f))
return (unsigned long) 0;
for (s = ULONG_MAX, prec = 0; s != 0; s /= 2, prec ++)
{ }
MPFR_SAVE_EXPO_MARK (expo);
/* first round to prec bits */
mpfr_init2 (x, prec);
mpfr_rint (x, f, rnd);
/* The flags from mpfr_rint are the wanted ones. In particular,
it sets the inexact flag when necessary. */
MPFR_SAVE_EXPO_UPDATE_FLAGS (expo, __gmpfr_flags);
/* warning: if x=0, taking its exponent is illegal */
if (MPFR_NOTZERO (x))
{
exp = MPFR_GET_EXP (x);
MPFR_ASSERTD (exp >= 1); /* since |x| >= 1 */
n = MPFR_LIMB_SIZE (x);
#ifdef MPFR_LONG_WITHIN_LIMB
MPFR_ASSERTD (exp <= GMP_NUMB_BITS);
#else
while (exp > GMP_NUMB_BITS)
{
MPFR_ASSERTD (n > 0);
s += (unsigned long) MPFR_MANT(x)[n - 1] << (exp - GMP_NUMB_BITS);
n--;
exp -= GMP_NUMB_BITS;
}
#endif
MPFR_ASSERTD (n > 0);
s += MPFR_MANT(x)[n - 1] >> (GMP_NUMB_BITS - exp);
}
mpfr_clear (x);
MPFR_SAVE_EXPO_FREE (expo);
return s;
}
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