fsfw/src/fsfw/tmtcpacket/SpacePacketBase.h

#ifndef FSFW_TMTCPACKET_SPACEPACKETBASE_H_
#define FSFW_TMTCPACKET_SPACEPACKETBASE_H_

#include "ccsds_header.h"
#include "fsfw/returnvalues/HasReturnvaluesIF.h"

#include <cstddef>

/**
 * @defgroup tmtcpackets Space Packets
 * This is the group, where all classes associated with Telecommand and
 * Telemetry packets belong to.
 * The class hierarchy resembles the dependency between the different standards
 * applied, namely the CCSDS Space Packet standard and the ECCSS Packet
 * Utilization Standard. Most field and structure names are taken from these
 * standards.
 */

/**
 * This struct defines the data structure of a Space Packet when accessed
 * via a pointer.
 * @ingroup tmtcpackets
 */
struct SpacePacketPointer {
    CCSDSPrimaryHeader header;
    uint8_t packet_data;
};

/**
 * This class is the basic data handler for any CCSDS Space Packet
 * compatible Telecommand and Telemetry packet.
 * It does not contain the packet data itself but a pointer to the
 * data must be set on instantiation. An invalid pointer may cause
 * damage, as no getter method checks data validity. Anyway, a NULL
 * check can be performed by making use of the getWholeData method.
 * Remark: All bit numbers in this documentation are counted from
 * the most significant bit (from left).
 * @ingroup tmtcpackets
 */
class SpacePacketBase {
protected:
    /**
     * A pointer to a structure which defines the data structure of
     * the packet header.
     * To be hardware-safe, all elements are of byte size.
     */
    SpacePacketPointer* data;
public:
    static const uint16_t LIMIT_APID = 2048; //2^1
    static const uint16_t LIMIT_SEQUENCE_COUNT = 16384; // 2^14
    static const uint16_t APID_IDLE_PACKET = 0x7FF;
    static const uint8_t TELECOMMAND_PACKET = 1;
    static const uint8_t TELEMETRY_PACKET = 0;
    /**
     * This definition defines the CRC size in byte.
     */
    static const uint8_t CRC_SIZE = 2;
    /**
     * This is the minimum size of a SpacePacket.
     */
    static const uint16_t MINIMUM_SIZE = sizeof(CCSDSPrimaryHeader) + CRC_SIZE;
    /**
     * This is the default constructor.
     * It sets its internal data pointer to the address passed.
     * @param set_address	The position where the packet data lies.
     */
    SpacePacketBase( const uint8_t* set_address );
    /**
     * No data is allocated, so the destructor is empty.
     */
    virtual ~SpacePacketBase();

    //CCSDS Methods

    /**
     * Getter for the packet version number field.
     * @return Returns the highest three bit of the packet in one byte.
     */
    uint8_t getPacketVersionNumber( void );
    /**
     * This method checks the type field in the header.
     * This bit specifies, if the command is interpreted as Telecommand of
     * as Telemetry. For a Telecommand, the bit is set.
     * @return Returns true if the bit is set and false if not.
     */
    bool isTelecommand( void );

    ReturnValue_t initSpacePacketHeader(bool isTelecommand, bool hasSecondaryHeader,
            uint16_t apid, uint16_t sequenceCount = 0);
    /**
     * The CCSDS header provides a secondary header flag (the fifth-highest bit),
     *  which is checked with this method.
     * @return	Returns true if the bit is set and false if not.
     */
    bool hasSecondaryHeader( void );
    /**
     * Returns the complete first two bytes of the packet, which together form
     * the CCSDS packet id.
     * @return	The CCSDS packet id.
     */
    uint16_t getPacketId( void );
    /**
     * Returns the APID of a packet, which are the lowest 11 bit of the packet
     * id.
     * @return The CCSDS APID.
     */
    uint16_t getAPID( void ) const;
    /**
     * Sets the APID of a packet, which are the lowest 11 bit of the packet
     * id.
     * @param 	The APID to set. The highest five bits of the parameter are
     * 			ignored.
     */
    void setAPID( uint16_t setAPID );

    /**
     * Sets the sequence flags of a packet, which are bit 17 and 18 in the space packet header.
     * @param   The sequence flags to set
     */
    void setSequenceFlags( uint8_t sequenceflags );

    /**
     * Returns the CCSDS packet sequence control field, which are the third and
     * the fourth byte of the CCSDS primary header.
     * @return The CCSDS packet sequence control field.
     */
    uint16_t getPacketSequenceControl( void );
    /**
     * Returns the SequenceFlags, which are the highest two bit of the packet
     * sequence control field.
     * @return	The CCSDS sequence flags.
     */
    uint8_t getSequenceFlags( void );
    /**
     * Returns the packet sequence count, which are the lowest 14 bit of the
     * packet sequence control field.
     * @return The CCSDS sequence count.
     */
    uint16_t getPacketSequenceCount( void ) const;
    /**
     * Sets the packet sequence count, which are the lowest 14 bit of the
     * packet sequence control field.
     * setCount is modulo-divided by \c LIMIT_SEQUENCE_COUNT to avoid overflows.
     * @param setCount	The value to set the count to.
     */
    void setPacketSequenceCount( uint16_t setCount );
    /**
     * Returns the packet data length, which is the fifth and sixth byte of the
     * CCSDS Primary Header. The packet data length is the size of every kind
     * of data \b after the CCSDS Primary Header \b -1.
     * @return
     * The CCSDS packet data length. uint16_t is sufficient,
     * because this is limit in CCSDS standard
     */
    uint16_t getPacketDataLength(void) const;
    /**
     * Sets the packet data length, which is the fifth and sixth byte of the
     * CCSDS Primary Header.
     * @param setLength The value of the length to set. It must fit the true
     * 					CCSDS packet data length . The packet data length is
     * 					the size of every kind of data \b after the CCSDS
     * 					Primary Header \b -1.
     */
    void setPacketDataLength( uint16_t setLength );

    // Helper methods
    /**
     * This method returns a raw uint8_t pointer to the packet.
     * @return	A \c uint8_t pointer to the first byte of the CCSDS primary header.
     */
    virtual uint8_t* getWholeData( void );

    uint8_t* getPacketData();
    /**
     * With this method, the packet data pointer can be redirected to another
     * location.
     * @param p_Data A pointer to another raw Space Packet.
     */
    virtual void setData( const uint8_t* p_Data );
    /**
     * This method returns the full raw packet size.
     * @return	The full size of the packet in bytes.
     */
    size_t getFullSize();

    uint32_t getApidAndSequenceCount() const;

};

#endif /* FSFW_TMTCPACKET_SPACEPACKETBASE_H_ */