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/*
Copyright (C) 2010 William Hart
Copyright (C) 2011 Fredrik Johansson
This file is part of FLINT.
FLINT is free software: you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License (LGPL) as published
by the Free Software Foundation; either version 3 of the License, or
(at your option) any later version. See <https://www.gnu.org/licenses/>.
*/
#include <gmp.h>
#include "longlong.h"
#include "fmpz.h"
#include "fmpz_vec.h"
slong
_fmpz_vec_max_bits(const fmpz * vec, slong len)
{
slong i, sign, max_limbs;
ulong max_limb;
slong 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_ptr 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));
}
slong
_fmpz_vec_max_bits_ref(const fmpz * vec, slong len)
{
slong i, bits, max_bits = 0, sign = 1;
for (i = 0; i < len; i++)
{
bits = fmpz_bits(vec + i);
if (bits > max_bits)
max_bits = bits;
if (fmpz_sgn(vec + i) < 0)
sign = WORD(-1);
}
return max_bits * sign;
}