fsfw/datalinklayer/DataLinkLayer.h

#ifndef DATALINKLAYER_H_
#define DATALINKLAYER_H_

#include "CCSDSReturnValuesIF.h"
#include "ClcwIF.h"
#include "TcTransferFrame.h"
#include "VirtualChannelReceptionIF.h"
#include "../events/Event.h"
#include <map>


class VirtualChannelReception;
/**
 * A complete representation of the CCSDS Data Link Layer.
 * The operations of this layer are defined in the CCSDS TC Space Data Link Protocol
 * document. It is configured to handle a VC Demultiplexing function. All reception
 * steps are performed.
 */
class DataLinkLayer : public CCSDSReturnValuesIF {
public:
	static const uint8_t SUBSYSTEM_ID = SUBSYSTEM_ID::SYSTEM_1;
	static const Event RF_AVAILABLE = MAKE_EVENT(0, SEVERITY::INFO); //!< A RF available signal was detected. P1: raw RFA state, P2: 0
	static const Event RF_LOST = MAKE_EVENT(1, SEVERITY::INFO); //!< A previously found RF available signal was lost. P1: raw RFA state, P2: 0
	static const Event BIT_LOCK = MAKE_EVENT(2, SEVERITY::INFO); //!< A Bit Lock signal. Was detected. P1: raw BLO state, P2: 0
	static const Event BIT_LOCK_LOST = MAKE_EVENT(3, SEVERITY::INFO); //!< A previously found Bit Lock signal was lost. P1: raw BLO state, P2: 0
//	static const Event RF_CHAIN_LOST = MAKE_EVENT(4, SEVERITY::INFO); //!< The CCSDS Board detected that either bit lock or RF available or both are lost. No parameters.
	static const Event FRAME_PROCESSING_FAILED = MAKE_EVENT(5, SEVERITY::LOW); //!< The CCSDS Board could not interpret a TC
	/**
	 * The Constructor sets the passed parameters and nothing else.
	 * @param set_frame_buffer The buffer in which incoming frame candidates are stored.
	 * @param setClcw	The CLCW class to work on when returning CLCW information.
	 * @param set_start_sequence_length	Length of the Start sequence in front of every TC Transfer Frame.
	 * @param set_scid	The SCID to operate on.
	 */
	DataLinkLayer( uint8_t* set_frame_buffer, ClcwIF* setClcw, uint8_t set_start_sequence_length, uint16_t set_scid );
	/**
	 * Empty virtual destructor.
	 */
	~DataLinkLayer();
	/**
	 * This method tries to process a frame that is placed in #frameBuffer.
	 * The procedures described in the Standard are performed.
	 * @param length	Length of the incoming frame candidate.
	 * @return	@c RETURN_OK on successful handling, otherwise the return codes of the higher methods.
	 */
	ReturnValue_t processFrame( uint16_t length );
	/**
	 * Configuration method to add a new TC Virtual Channel.
	 * Shall only be called during initialization. As soon as the method was called, the layer can
	 * handle Frames directed to this VC.
	 * @param virtualChannelId	Id of the VC. Shall be smaller than 64.
	 * @param object	Reference to the object that handles the Frame.
	 * @return	@c RETURN_OK on success, @c RETURN_FAILED otherwise.
	 */
	ReturnValue_t addVirtualChannel( uint8_t virtualChannelId, VirtualChannelReceptionIF* object );
	/**
	 * The initialization method calls the @c initialize routine of all virtual channels.
	 * @return The return code of the first failed VC initialization or @c RETURN_OK.
	 */
	ReturnValue_t initialize();
private:
	typedef std::map<uint8_t, VirtualChannelReceptionIF*>::iterator virtualChannelIterator; //!< Typedef to simplify handling the #virtualChannels map.
	static const uint8_t FRAME_VERSION_NUMBER_DEFAULT = 0x00;	//!< Constant for the default value of Frame Version Numbers.
	static const uint8_t FRAME_PRIMARY_HEADER_LENGTH = 5;	//!< Length of the frame's primary header.
	static const uint8_t START_SEQUENCE_PATTERN = 0x00; //!< The start sequence pattern which might be with the frame.
	static const bool USE_CRC = true;	//!< A global, so called "Managed Parameter" that identifies if incoming frames have CRC's or not.
	uint16_t spacecraftId;	//!< The Space Craft Identifier (SCID) configured.
	uint8_t* frameBuffer;	//!< A pointer to point to the current incoming frame.
	ClcwIF* clcw;	//!< Pointer to store the CLCW to work on.
	uint16_t receivedDataLength;	//!< Stores the length of the currently processed frame.
	TcTransferFrame currentFrame;	//!< Stores a more convenient access to the current frame.
	uint8_t startSequenceLength;	//!< Configured length of the start sequence. Maybe this must be done more variable.
	std::map<uint8_t, VirtualChannelReceptionIF*> virtualChannels;	//!< Map of all virtual channels assigned.
	/**
	 * Method that performs all possible frame validity checks (as specified).
	 * @return	Various error codes or @c RETURN_OK on success.
	 */
	ReturnValue_t frameValidationCheck();
	/**
	 * First method to call.
	 * Removes start sequence bytes and checks if the complete frame was received.
	 * SHOULDDO: Maybe handling the start sequence must be done more variable.
	 * @return @c RETURN_OK or @c TOO_SHORT.
	 */
	ReturnValue_t frameDelimitingAndFillRemoval();
	/**
	 * Small helper method to check the CRC of the Frame.
	 * @return @c RETURN_OK or @c CRC_FAILED.
	 */
	ReturnValue_t frameCheckCRC();
	/**
	 * Method that groups the reception process of all Frames.
	 * Calls #frameDelimitingAndFillRemoval and #frameValidationCheck.
	 * @return The return codes of the sub calls.
	 */
	ReturnValue_t allFramesReception();
	/**
	 * Dummy method for master channel demultiplexing.
	 * As there's only one Master Channel here, the method calls #virtualChannelDemultiplexing.
	 * @return	The return codes of #virtualChannelDemultiplexing.
	 */
	ReturnValue_t masterChannelDemultiplexing();
	/**
	 * Method to demultiplex the Frames to Virtual Channels (VC's).
	 * Looks up the requested VC in #virtualChannels and forwards the Frame to its
	 * #frameAcceptanceAndReportingMechanism method, if found.
	 * @return The higher method codes or @c VC_NOT_FOUND.
	 */
	ReturnValue_t virtualChannelDemultiplexing();
};

#endif /* DATALINKLAYER_H_ */