fsfw/datalinklayer/VirtualChannelReception.h

/**
 * @file	VirtualChannelReception.h
 * @brief	This file defines the VirtualChannelReception class.
 * @date	25.03.2013
 * @author	baetz
 */

#ifndef VIRTUALCHANNELRECEPTION_H_
#define VIRTUALCHANNELRECEPTION_H_

#include "CCSDSReturnValuesIF.h"
#include "Clcw.h"
#include "Farm1StateIF.h"
#include "Farm1StateLockout.h"
#include "Farm1StateOpen.h"
#include "Farm1StateWait.h"
#include "MapPacketExtractionIF.h"
#include "VirtualChannelReceptionIF.h"
#include <map>
/**
 * Implementation of a TC Virtual Channel.
 * This is a full implementation of a virtual channel as specified in the CCSDS TC Space Data Link
 * Protocol. It is designed to operate within an instance of the @c DataLinkLayer class.
 * Features:
 *  - any (6bit) Virtual Channel ID is assignable.
 *  - Supports an arbitrary number of MAP Channels (with a map).
 *  - Has a complete FARM-1 Machine built-in.
 *
 * The FARM-1 state machine uses the State Pattern.
 */
class VirtualChannelReception : public VirtualChannelReceptionIF, public CCSDSReturnValuesIF {
	friend class Farm1StateOpen;
	friend class Farm1StateWait;
	friend class Farm1StateLockout;
private:
	uint8_t channelId;	//!< Stores the VCID that was assigned on construction.
	uint8_t slidingWindowWidth;	//!< A constant to set the FARM-1 sliding window width.
	uint8_t positiveWindow;	//!< The positive window for the FARM-1 machine.
	uint8_t negativeWindow; //!< The negative window for the FARM-1 machine.
protected:
	Farm1StateIF* currentState;	//!< The current state. To change, one of the other states must be assigned to this pointer.
	Farm1StateOpen openState;	//!< Instance of the FARM-1 State "Open".
	Farm1StateWait waitState;	//!< Instance of the FARM-1 State "Wait".
	Farm1StateLockout lockoutState;	//!< Instance of the FARM-1 State "Lockout".
	Clcw internalClcw;	//!< A CLCW class to internally set the values before writing them back to the TTC System.
	uint8_t vR;	//!< The Receiver Frame Sequence Number V(R) as it shall be maintained for every Virtual Channel.
	uint8_t farmBCounter;	//!< The FARM-B COunter as it shall be maintained for every Virtual Channel.
	typedef std::map<uint8_t, MapPacketExtractionIF*>::iterator mapChannelIterator;	//!< Typedef to simplify handling of the mapChannels map.
	std::map<uint8_t, MapPacketExtractionIF*> mapChannels;	//!< A map that maintains all map Channels. Channels must be configured on initialization. MAy be omitted in a simplified version.
	/**
	 * This method handles demultiplexing to different map channels.
	 * It parses the entries of #mapChannels and forwards the Frame to a found MAP Channel.
	 * @param frame	The frame to forward.
	 * @return	#VC_NOT_FOUND or the return value of the map channel extraction.
	 */
	ReturnValue_t mapDemultiplexing( TcTransferFrame* frame );
	/**
	 * A sub-method that actually does the FARM-1 handling for different Frame types.
	 * @param frame	The Tc Transfer Frame to handle.
	 * @param clcw	Any changes on the CLCW shall be done with this method.
	 * @return	The return code of higher methods or @c ILLEGAL_FLAG_COMBINATION.
	 */
	ReturnValue_t doFARM(TcTransferFrame* frame, ClcwIF* clcw);
	/**
	 * Handles incoming BD Frames.
	 * Handling these Frames is independent of the State, so no subcall to #currentState is
	 * required.
	 * @param frame	The Tc Transfer Frame to handle.
	 * @param clcw	Any changes on the CLCW shall be done with this method.
	 * @return Always returns @c RETURN_OK.
	 */
	ReturnValue_t handleBDFrame( TcTransferFrame* frame, ClcwIF* clcw );
	/**
	 * Handles incoming BC Frames.
	 * The type of the BC Frame is detected and checked first, then methods of #currentState are called.
	 * @param frame	The Tc Transfer Frame to handle.
	 * @param clcw	Any changes on the CLCW shall be done with this method.
	 * @return The failure code of BC Frame interpretation or the return code of higher methods.
	 */
	ReturnValue_t handleBCFrame( TcTransferFrame* frame, ClcwIF* clcw );
public:
	/**
	 * Default constructor.
	 * Only sets the channelId of the channel. Setting the Sliding Window width is possible as well.
	 * @param setChannelId	Virtual Channel Identifier (VCID) of the channel.
	 */
	VirtualChannelReception( uint8_t setChannelId, uint8_t setSlidingWindowWidth );
	ReturnValue_t frameAcceptanceAndReportingMechanism( TcTransferFrame* frame, ClcwIF* clcw );
	/**
	 * Helper method to simplify adding a mapChannel during construction.
	 * @param mapId	The mapId of the object to add.
	 * @param object	Pointer to the MapPacketExtraction object itself.
	 * @return	@c RETURN_OK if the channel was successfully inserted, @c RETURN_FAILED otherwise.
	 */
	ReturnValue_t addMapChannel( uint8_t mapId, MapPacketExtractionIF* object );
	/**
	 * The initialization routine checks the set #slidingWindowWidth and initializes all MAP
	 * channels.
	 * @return	@c RETURN_OK on successful initialization, @c RETURN_FAILED otherwise.
	 */
	ReturnValue_t initialize();
	/**
	 * Getter for the VCID.
	 * @return	The #channelId.
	 */
	uint8_t getChannelId() const;
	/**
	 * Small method to set the state to Farm1StateWait.
	 */
	void setToWaitState();
};


#endif /* VIRTUALCHANNELRECEPTION_H_ */