/*

 * tc_core.c		TC core library.

 *

 *		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.

 *

 * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>

 *

 */

#include <stdio.h>

#include <stdlib.h>

#include <unistd.h>

#include <fcntl.h>

#include <math.h>

#include <sys/socket.h>

#include <netinet/in.h>

#include <arpa/inet.h>

#include <string.h>

#include "utils.h"

#include "tc_core.h"

int tc_setup_estimator(unsigned int A, unsigned int time_const, struct tc_estimator *est)

{

	for (est->interval = 0; est->interval <= 5; est->interval++) {

		if (A <= (1<<est->interval)*(TIME_UNITS_PER_SEC/4))

			break;

	}

	if (est->interval > 5)

		return -1;

	est->interval -= 2;

	for (est->ewma_log = 1; est->ewma_log < 32; est->ewma_log++) {

		double w = 1.0 - 1.0/(1<<est->ewma_log);

		if (A/(-log(w)) > time_const)

			break;

	}

	est->ewma_log--;

	if (est->ewma_log == 0 || est->ewma_log >= 31)

		return -1;

	return 0;

}