fsfw/tmtcpacket/SpacePacketBase.h
2020-08-13 20:53:35 +02:00

177 lines
5.8 KiB
C++

#ifndef SPACEPACKETBASE_H_
#define SPACEPACKETBASE_H_
#include "ccsds_header.h"
/**
* \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 );
void 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 );
/**
* 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 getPacketDataLength( void ); //uint16_t is sufficient, because this is limit in CCSDS standard
/**
* 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.
*/
uint32_t getFullSize();
uint32_t getApidAndSequenceCount() const;
};
#endif /* SPACEPACKETBASE_H_ */