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/* mpfr_isinteger -- test if a mpfr variable is integer
Copyright 2001, 2002 Free Software Foundation, Inc.
This file is part of the MPFR Library.
The 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 2.1 of the License, or (at your
option) any later version.
The 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 MPFR Library; see the file COPYING.LIB. If not, write to
the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
MA 02111-1307, USA. */
#include "gmp.h"
#include "gmp-impl.h"
#include "mpfr.h"
#include "mpfr-impl.h"
int
mpfr_isinteger (mpfr_srcptr x)
{
mp_exp_t expo;
mp_prec_t prec;
mp_size_t xn;
mp_limb_t *xp;
if (!MPFR_IS_FP(x))
return 0;
if (MPFR_IS_ZERO(x))
return 1;
expo = MPFR_EXP(x);
if (expo <= 0)
return 0;
prec = MPFR_PREC(x);
if (expo >= prec)
return 1;
/* 0 < expo < prec */
xn = (prec - 1) / BITS_PER_MP_LIMB; /* index of last limb */
xn -= (mp_size_t) (expo / BITS_PER_MP_LIMB);
/* now the index of the last limb containing bits of the fractional part */
xp = MPFR_MANT(x);
MPFR_ASSERTN(xn >= 0);
if (xp[xn] << (expo % BITS_PER_MP_LIMB) != 0)
return 0;
while (--xn >= 0)
if (xp[xn] != 0)
return 0;
return 1;
}
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