pqc/external/flint-2.4.3/fmpz_poly/sqr_KS.c

112 lines
2.9 KiB
C

/*=============================================================================
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) 2008, 2009 William Hart
Copyright (C) 2010, 2011 Sebastian Pancratz
******************************************************************************/
#include <stdlib.h>
#include <gmp.h>
#include "flint.h"
#include "fmpz.h"
#include "fmpz_vec.h"
#include "fmpz_poly.h"
void
_fmpz_poly_sqr_KS(fmpz *rop, const fmpz *op, slong len)
{
const slong in_len = len;
int neg;
slong bits, limbs, loglen;
mp_limb_t *arr, *arr3;
slong sign = 0;
FMPZ_VEC_NORM(op, len);
if (!len)
{
if (2 * in_len - 1 > 0)
_fmpz_vec_zero(rop, 2 * in_len - 1);
return;
}
neg = (fmpz_sgn(op + len - 1) > 0) ? 0 : -1;
bits = _fmpz_vec_max_bits(op, len);
if (bits < 0)
{
sign = 1;
bits = - bits;
}
loglen = FLINT_BIT_COUNT(len);
bits = 2 * bits + loglen + sign;
limbs = (bits * len - 1) / FLINT_BITS + 1;
arr = (mp_limb_t *) flint_calloc(limbs, sizeof(mp_limb_t));
_fmpz_poly_bit_pack(arr, op, len, bits, neg);
arr3 = (mp_limb_t *) flint_malloc((2 * limbs) * sizeof(mp_limb_t));
mpn_sqr(arr3, arr, limbs);
if (sign)
_fmpz_poly_bit_unpack(rop, 2 * len - 1, arr3, bits, 0);
else
_fmpz_poly_bit_unpack_unsigned(rop, 2 * len - 1, arr3, bits);
if (len < in_len)
_fmpz_vec_zero(rop + (2 * len - 1), 2 * (in_len - len));
flint_free(arr);
flint_free(arr3);
}
void fmpz_poly_sqr_KS(fmpz_poly_t rop, const fmpz_poly_t op)
{
slong len;
if (op->length == 0)
{
fmpz_poly_zero(rop);
return;
}
len = 2 * op->length - 1;
if (rop == op)
{
fmpz_poly_t t;
fmpz_poly_init2(t, len);
fmpz_poly_sqr_KS(t, op);
fmpz_poly_swap(rop, t);
fmpz_poly_clear(t);
return;
}
fmpz_poly_fit_length(rop, len);
_fmpz_poly_sqr_KS(rop->coeffs, op->coeffs, op->length);
_fmpz_poly_set_length(rop, len);
}