/*

* Copyright (c) 2010 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description: 

*

*/

#ifndef STATEMACHINE_H_

#define STATEMACHINE_H_

#include <stdint.h>

namespace analysis {

	typedef uint8_t byte_t; 

	/**

	 * Points to the beginning of the state in the memory

	 */

	typedef byte_t* StatePointer;

	/**

	 * Points to the begining of the state as calculated

	 * from the beginning of the state machine blob. Can be

	 * turned into a StatePointer by combining it with the 

	 * state machine blob pointer. 

	 */

	typedef unsigned int StateOffset;

	/**

	 * Can be used for navigating throught the state machine

	 * staets. In a sense 'a pointer' to some state. Can be used 

	 * to read information of the state or to jump to another location

	 * Must be reset before usage.

	 * 

	 * @tparam Encoding describes encoding of the state machine binary

	 */

	template <class Encoding>

	class StateCursor {

	public:

		/** Constructs the cursor. */

		StateCursor();

		/** 

		 * Resets the state cursor to point to a new location. After

		 * first reset other methods can be used.

		 * @param blob State machine binary. Ownership NOT transferred 

		 * @param offset Points to a state within the state machine binary 

		 */

		void reset(byte_t* blob, StateOffset offset);

		/** 

		 * Describes, if this state is a terminal state.

		 * @note Must not be used before reset() is once called  

		 */

		bool isFinal();

		/** 

		 * Moves to next state based on the input. Returns false, 

		 * if no transition for input was found.

		 * @note Must not be used before reset() is once called  

		 * @param c An input character. 

		 * @returns True, if state did change, false otherwise  

		 */

		bool next(wchar_t c);

	private: 

		/** State machine binary. Does NOT hold ownership */

		byte_t* blob_; 

		/** Raw memory pointer to the state. State is within state machine binary */

		StatePointer pointer_; 

	};

	/**

	 * Represents the state machine. Mainly wraps the state machine binary.

	 * Can be used to reset StateCursors

	 *   

	 * @tparam Encoding describes the encoding of the state machine binary

	 */

	template<class Encoding>

	class StateMachine {

		public: 

			static const StateOffset ROOT_STATE_OFFSET;

		public:

			/** 

			 * Constructs state. State machine is not functional, before

			 * reset is called

			 */

			StateMachine();

			/**

			 * Loads the state machine with the state machine binary.

			 * @param blob The state machine binary. Ownership is NOT transferred.

			 */

			void reset(byte_t* blob); 

			/**

			 * Resets the cursor to point out to this state machine's

			 * root state.

			 * @param cursor this cursor is set to point to the state machine's root state. 

			 * @note Must not be called before StateMachine is properly reset

			 */

			void rootState(StateCursor<Encoding>& cursor);

		private: 

			/** State machine binary. Does NOT hold ownership */

			byte_t* blob_;

	};

}

#include "statemachine.inl"

#endif /* STATEMACHINE_H_ */