fsfw/src/fsfw/tmtcpacket/SpacePacketBase.h

#ifndef FSFW_TMTCPACKET_SPACEPACKETBASE_H_
#define FSFW_TMTCPACKET_SPACEPACKETBASE_H_

#include <fsfw/tmtcpacket/RedirectableDataPointerIF.h>

#include <cstddef>

#include "ccsds_header.h"
#include "fsfw/returnvalues/returnvalue.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 : virtual public RedirectableDataPointerIF {
 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 ReturnValue_t setData(uint8_t* p_Data, size_t maxSize, void* args = nullptr) override;
  /**
   * 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_ */