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/*=============================================================================
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) 2011 Fredrik Johansson
******************************************************************************/
#include <gmp.h>
#include "flint.h"
#include "fmpz.h"
#include "fmpz_vec.h"
slong
_fmpz_vec_max_bits(const fmpz * vec, slong len)
{
slong i, sign, max_limbs;
mp_limb_t max_limb;
mp_size_t limbs;
sign = 1;
max_limb = 0;
for (i = 0; i < len; i++)
{
fmpz c = vec[i];
if (c >= 0)
{
if (c > COEFF_MAX)
goto bignum;
max_limb |= c;
}
else
{
if (c < COEFF_MIN)
goto bignum;
max_limb |= -c;
sign = -1;
}
}
return sign * FLINT_BIT_COUNT(max_limb);
bignum:
max_limbs = 1;
for ( ; i < len; i++)
{
fmpz c = vec[i];
if (COEFF_IS_MPZ(c))
{
__mpz_struct * z = COEFF_TO_PTR(c);
limbs = z->_mp_size;
if (limbs < 0)
{
sign = -1;
limbs = -limbs;
}
if (limbs == max_limbs)
max_limb |= z->_mp_d[limbs - 1];
else if (limbs > max_limbs)
{
max_limb = z->_mp_d[limbs - 1];
max_limbs = limbs;
}
}
else if (c < 0)
sign = -1;
}
return sign * ((max_limbs - 1) * FLINT_BITS + FLINT_BIT_COUNT(max_limb));
}
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