fsfw/tmtcpacket/pus/TcPacketBase.h

188 lines
5.7 KiB
C++

#ifndef TMTCPACKET_PUS_TCPACKETBASE_H_
#define TMTCPACKET_PUS_TCPACKETBASE_H_
#include "../../tmtcpacket/SpacePacketBase.h"
#include <cstddef>
/**
* This struct defines a byte-wise structured PUS TC Data Field Header.
* Any optional fields in the header must be added or removed here.
* Currently, the Source Id field is present with one byte.
* @ingroup tmtcpackets
*/
struct PUSTcDataFieldHeader {
uint8_t version_type_ack;
uint8_t service_type;
uint8_t service_subtype;
uint8_t source_id;
};
/**
* This struct defines the data structure of a PUS Telecommand Packet when
* accessed via a pointer.
* @ingroup tmtcpackets
*/
struct TcPacketPointer {
CCSDSPrimaryHeader primary;
PUSTcDataFieldHeader dataField;
uint8_t appData;
};
/**
* This class is the basic data handler for any ECSS PUS Telecommand packet.
*
* In addition to #SpacePacketBase, the class provides methods to handle
* the standardized entries of the PUS TC Packet Data Field Header.
* 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.
* @ingroup tmtcpackets
*/
class TcPacketBase : public SpacePacketBase {
public:
static const uint16_t TC_PACKET_MIN_SIZE = (sizeof(CCSDSPrimaryHeader) +
sizeof(PUSTcDataFieldHeader) + 2);
enum AckField {
//! No acknowledgements are expected.
ACK_NONE = 0b0000,
//! Acknowledgements on acceptance are expected.
ACK_ACCEPTANCE = 0b0001,
//! Acknowledgements on start are expected.
ACK_START = 0b0010,
//! Acknowledgements on step are expected.
ACK_STEP = 0b0100,
//! Acknowledfgement on completion are expected.
ACK_COMPLETION = 0b1000
};
static constexpr uint8_t ACK_ALL = ACK_ACCEPTANCE | ACK_START | ACK_STEP |
ACK_COMPLETION;
/**
* This is the default constructor.
* It sets its internal data pointer to the address passed and also
* forwards the data pointer to the parent SpacePacketBase class.
* @param setData The position where the packet data lies.
*/
TcPacketBase( const uint8_t* setData );
/**
* This is the empty default destructor.
*/
virtual ~TcPacketBase();
/**
* This command returns the CCSDS Secondary Header Flag.
* It shall always be zero for PUS Packets. This is the
* highest bit of the first byte of the Data Field Header.
* @return the CCSDS Secondary Header Flag
*/
uint8_t getSecondaryHeaderFlag();
/**
* This command returns the TC Packet PUS Version Number.
* The version number of ECSS PUS 2003 is 1.
* It consists of the second to fourth highest bits of the
* first byte.
* @return
*/
uint8_t getPusVersionNumber();
/**
* This is a getter for the packet's Ack field, which are the lowest four
* bits of the first byte of the Data Field Header.
*
* It is packed in a uint8_t variable.
* @return The packet's PUS Ack field.
*/
uint8_t getAcknowledgeFlags();
/**
* This is a getter for the packet's PUS Service ID, which is the second
* byte of the Data Field Header.
* @return The packet's PUS Service ID.
*/
uint8_t getService();
/**
* This is a getter for the packet's PUS Service Subtype, which is the
* third byte of the Data Field Header.
* @return The packet's PUS Service Subtype.
*/
uint8_t getSubService();
/**
* This is a getter for a pointer to the packet's Application data.
*
* These are the bytes that follow after the Data Field Header. They form
* the packet's application data.
* @return A pointer to the PUS Application Data.
*/
const uint8_t* getApplicationData() const;
/**
* This method calculates the size of the PUS Application data field.
*
* It takes the information stored in the CCSDS Packet Data Length field
* and subtracts the Data Field Header size and the CRC size.
* @return The size of the PUS Application Data (without Error Control
* field)
*/
uint16_t getApplicationDataSize();
/**
* This getter returns the Error Control Field of the packet.
*
* The field is placed after any possible Application Data. If no
* Application Data is present there's still an Error Control field. It is
* supposed to be a 16bit-CRC.
* @return The PUS Error Control
*/
uint16_t getErrorControl();
/**
* With this method, the Error Control Field is updated to match the
* current content of the packet.
*/
void setErrorControl();
/**
* This is a debugging helper method that prints the whole packet content
* to the screen.
*/
void print();
/**
* Calculate full packet length from application data length.
* @param appDataLen
* @return
*/
static size_t calculateFullPacketLength(size_t appDataLen);
protected:
/**
* A pointer to a structure which defines the data structure of
* the packet's data.
*
* To be hardware-safe, all elements are of byte size.
*/
TcPacketPointer* tcData;
/**
* Initializes the Tc Packet header.
* @param apid APID used.
* @param sequenceCount Sequence Count in the primary header.
* @param ack Which acknowledeges are expected from the receiver.
* @param service PUS Service
* @param subservice PUS Subservice
*/
void initializeTcPacket(uint16_t apid, uint16_t sequenceCount, uint8_t ack,
uint8_t service, uint8_t subservice);
/**
* With this method, the packet data pointer can be redirected to another
* location.
* This call overwrites the parent's setData method to set both its
* @c tc_data pointer and the parent's @c data pointer.
*
* @param p_data A pointer to another PUS Telecommand Packet.
*/
void setData( const uint8_t* pData );
};
#endif /* TMTCPACKET_PUS_TCPACKETBASE_H_ */