/**

 * @file mave.c

 * @note Copyright (C) 2011 Richard Cochran <richardcochran@gmail.com>

 *

 * This program 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.

 *

 * This program 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 this program; if not, write to the Free Software Foundation, Inc.,

 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

 */

#include <stdlib.h>

#include <string.h>

#include "mave.h"

#include "filter_private.h"

struct mave {

	struct filter filter;

	int cnt;

	int len;

	int index;

	tmv_t sum;

	tmv_t *val;

};

static void mave_destroy(struct filter *filter)

{

	struct mave *m = container_of(filter, struct mave, filter);

	free(m->val);

	free(m);

}

static tmv_t mave_accumulate(struct filter *filter, tmv_t val)

{

	struct mave *m = container_of(filter, struct mave, filter);

	m->sum = tmv_sub(m->sum, m->val[m->index]);

	m->val[m->index] = val;

	m->index = (1 + m->index) % m->len;

	m->sum = tmv_add(m->sum, val);

	if (m->cnt < m->len) {

		m->cnt++;

	}

	return tmv_div(m->sum, m->cnt);

}

static void mave_reset(struct filter *filter)

{

	struct mave *m = container_of(filter, struct mave, filter);

	m->cnt = 0;

	m->index = 0;

	m->sum = tmv_zero();

	memset(m->val, 0, m->len * sizeof(*m->val));

}

struct filter *mave_create(int length)

{

	struct mave *m;

	m = calloc(1, sizeof(*m));

	if (!m) {

		return NULL;

	}

	m->filter.destroy = mave_destroy;

	m->filter.sample = mave_accumulate;

	m->filter.reset = mave_reset;

	m->val = calloc(1, length * sizeof(*m->val));

	if (!m->val) {

		free(m);

		return NULL;

	}

	m->len = length;

	return &m->filter;

}