pqc/external/flint-2.4.3/fmpz_mod_poly/mul.c

85 lines
2.8 KiB
C
Raw Normal View History

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) 2011 Sebastian Pancratz
Copyright (C) 2010 William Hart
******************************************************************************/
#include <gmp.h>
#include "flint.h"
#include "fmpz.h"
#include "fmpz_poly.h"
#include "fmpz_mod_poly.h"
void _fmpz_mod_poly_mul(fmpz *res, const fmpz *poly1, slong len1,
const fmpz *poly2, slong len2, const fmpz_t p)
{
_fmpz_poly_mul(res, poly1, len1, poly2, len2);
_fmpz_vec_scalar_mod_fmpz(res, res, len1 + len2 - 1, p);
}
void fmpz_mod_poly_mul(fmpz_mod_poly_t res,
const fmpz_mod_poly_t poly1, const fmpz_mod_poly_t poly2)
{
const slong len1 = poly1->length;
const slong len2 = poly2->length;
const slong lenr = len1 + len2 - 1;
if ((len1 == 0) || (len2 == 0))
{
fmpz_mod_poly_zero(res);
return;
}
if ((res == poly1) || (res == poly2))
{
fmpz *t = _fmpz_vec_init(lenr);
if (len1 >= len2)
_fmpz_mod_poly_mul(t, poly1->coeffs, len1,
poly2->coeffs, len2, &(res->p));
else
_fmpz_mod_poly_mul(t, poly2->coeffs, len2,
poly1->coeffs, len1, &(res->p));
_fmpz_vec_clear(res->coeffs, res->alloc);
res->alloc = lenr;
res->length = lenr;
res->coeffs = t;
}
else
{
fmpz_mod_poly_fit_length(res, lenr);
if (len1 >= len2)
_fmpz_mod_poly_mul(res->coeffs, poly1->coeffs, len1,
poly2->coeffs, len2, &(res->p));
else
_fmpz_mod_poly_mul(res->coeffs, poly2->coeffs, len2,
poly1->coeffs, len1, &(res->p));
_fmpz_mod_poly_set_length(res, lenr);
}
_fmpz_mod_poly_normalise(res);
}