/****************************************************************************
 *
 *   Copyright (C) 2013-2014 PX4 Development Team. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name PX4 nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ****************************************************************************/

/**
 * @file state_table.h
 *
 * Finite-State-Machine helper class for state table
 * @author: Julian Oes <julian@oes.ch>
 */

#ifndef __SYSTEMLIB_STATE_TABLE_H
#define __SYSTEMLIB_STATE_TABLE_H

class StateTable
{
public:
	typedef void (StateTable::*Action)();
	struct Tran {
		Action action;
		unsigned nextState;
	};

	StateTable(Tran const *table, unsigned nStates, unsigned nSignals)
		: myState(0), myTable(table), myNsignals(nSignals) {}

	StateTable(const StateTable &) = delete;
	StateTable &operator=(const StateTable &) = delete;

#define NO_ACTION &StateTable::doNothing
#define ACTION(_target) StateTable::Action(_target)

	virtual ~StateTable() {}

	void dispatch(unsigned const sig)
	{
		/* get transition using state table */
		Tran const *t = myTable + myState * myNsignals + sig;

		/* accept new state */
		myState = t->nextState;

		/*  */
		(this->*(t->action))();
	}
	void doNothing()
	{
		return;
	}
protected:
	unsigned myState;
private:
	Tran const *myTable;
	unsigned myNsignals;
};

#endif
