pqc/external/flint-2.4.3/fmpz_poly/bit_pack.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) 2010 William Hart
******************************************************************************/
#include <gmp.h>
#include "flint.h"
#include "fmpz.h"
#include "fmpz_poly.h"
void
_fmpz_poly_bit_pack(mp_ptr arr, const fmpz * poly, slong len,
mp_bitcnt_t bit_size, int negate)
{
mp_bitcnt_t bits = 0;
mp_size_t limbs = 0;
mp_bitcnt_t b = bit_size % FLINT_BITS;
mp_size_t l = bit_size / FLINT_BITS;
int borrow = 0;
slong i;
for (i = 0; i < len; i++)
{
borrow =
fmpz_bit_pack(arr + limbs, bits, bit_size, poly + i, negate,
borrow);
limbs += l;
bits += b;
if (bits >= FLINT_BITS)
{
bits -= FLINT_BITS;
limbs++;
}
}
}
void
fmpz_poly_bit_pack(fmpz_t f, const fmpz_poly_t poly,
mp_bitcnt_t bit_size)
{
slong len;
__mpz_struct * mpz;
slong i, d;
int negate;
len = fmpz_poly_length(poly);
if (len == 0 || bit_size == 0)
{
fmpz_zero(f);
return;
}
mpz = _fmpz_promote(f);
mpz_realloc2(mpz, len * bit_size);
d = mpz->_mp_alloc;
flint_mpn_zero(mpz->_mp_d, d);
if (fmpz_sgn(fmpz_poly_lead(poly)) < 0)
negate = -1;
else
negate = 0;
_fmpz_poly_bit_pack(mpz->_mp_d, poly->coeffs, len, bit_size, negate);
for (i = d - 1; i >= 0; i--)
{
if (mpz->_mp_d[i] != 0)
break;
}
d = i + 1;
mpz->_mp_size = d;
_fmpz_demote_val(f);
if (negate)
fmpz_neg(f, f);
}