/*=============================================================================

    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) 2007, David Howden.
    Copyright (C) 2010 William Hart

******************************************************************************/

#include <stdlib.h>
#include <gmp.h>
#include "flint.h"
#include "nmod_vec.h"
#include "nmod_poly.h"

void
_nmod_poly_add(mp_ptr res, mp_srcptr poly1, slong len1, mp_srcptr poly2,
               slong len2, nmod_t mod)
{
    slong i, min = FLINT_MIN(len1, len2);

    _nmod_vec_add(res, poly1, poly2, min, mod);

    if (poly1 != res)           /* copy any remaining coefficients from poly1 */
        for (i = min; i < len1; i++)
            res[i] = poly1[i];

    if (poly2 != res)           /* copy any remaining coefficients from poly2 */
        for (i = min; i < len2; i++)
            res[i] = poly2[i];
}

void
nmod_poly_add(nmod_poly_t res, const nmod_poly_t poly1,
              const nmod_poly_t poly2)
{
    slong max = FLINT_MAX(poly1->length, poly2->length);

    nmod_poly_fit_length(res, max);

    _nmod_poly_add(res->coeffs, poly1->coeffs, poly1->length, poly2->coeffs,
                   poly2->length, poly1->mod);

    res->length = max;
    _nmod_poly_normalise(res);  /* there may have been cancellation */
}
