pqc/external/flint-2.4.3/fmpz/set_mpz.c

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2014-05-18 22:03:37 +00:00
/*=============================================================================
This file is part of FLINT.
FLINT is free software; you can redistribute it and/or modify
it under the terms of 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.
FLINT 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 a copy of the GNU General Public License
along with FLINT; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
=============================================================================*/
/******************************************************************************
Copyright (C) 2009 William Hart
******************************************************************************/
#include <gmp.h>
#include "flint.h"
#include "ulong_extras.h"
#include "fmpz.h"
void
fmpz_set_mpz(fmpz_t f, const mpz_t x)
{
slong size = (slong) x->_mp_size;
if (size == WORD(0)) /* x is zero */
{
fmpz_zero(f);
}
else if (size == WORD(1)) /* x is positive and 1 limb */
{
fmpz_set_ui(f, flint_mpz_get_ui(x));
}
else if (size == WORD(-1)) /* x is negative and 1 limb */
{
ulong uval = flint_mpz_get_ui(x);
if (uval <= COEFF_MAX) /* x is small */
{
_fmpz_demote(f);
*f = -uval;
}
else /* x is large but one limb */
{
__mpz_struct *mpz_ptr = _fmpz_promote(f);
flint_mpz_set_ui(mpz_ptr, uval);
mpz_neg(mpz_ptr, mpz_ptr);
}
}
else /* x is more than one limb */
{
__mpz_struct *mpz_ptr = _fmpz_promote(f);
mpz_set(mpz_ptr, x);
}
}