Alphabetic Class Index | Class Inheritance Tree Index | Tool Index

Class: CCSDSPacket

Parent class: CCSDSHead

Description:
This class represents a generic CCSDS telemetry packet. Such a packet consists of a 6 byte CCSDS primary header followed by some number of data bytes.

This class may be subclassed to handle secondary, etc. headers. A number of such sub-classes have been written for the Swift mission.

Data Fields

public static const int SEQUENCE_PERIOD

public static const int SEQUENCE_HALF_PERIOD

public static const int MAX_LENGTH

private unsigned char* _data

private int array_size

Constructors / Destructor

protected CCSDSPacket(const CCSDSPacket& orig)
Copy constructor.

public CCSDSPacket()
Constructor - Creates a packet with zero data size. Note that by CCSDS rules a packet must have at least one data byte, so the size(int) method should be called before anything serious is done with the packet.

public CCSDSPacket(int size)
Constructor - Create a packet with a given number of data bytes.

public ~CCSDSPacket()
Destructor - frees storage allocated for the data array.

Methods

public virtual
constant unsigned char* data()

public virtual
constant int size()
Return the number of bytes in the data field.

public virtual void size(int size)
Resize the data field to a given number of bytes.

public virtual
constant unsigned int length()

public virtual void length(unsigned int value)
Override the CCSDSHeader versions of the length method to tie it to the data array size.

public virtual Reader* dataReader()
Return a pointer to a Reader object pointing to the data block of this packet. This is a new object which should be deleted when you are done with it.

public virtual Writer* dataWriter()
Return a pointer to a Reader object pointing to the data block of this packet. This is a new object which should be deleted when you are done with it.

public virtual int minimumLength()
Returns the minimum allowed value of the length field in the primary headewr for this type of packet. .

public virtual void read(const CCSDSHead& head, Reader* r)
Copy the given primary header into the packet and then read the rest of the packet. This method is useful if you want to read the packet in different ways depending on the APID. .
Throws: Interpreter::Exception

public virtual void read(Reader* r)
Read the entire packet.
Throws: Interpreter::Exception

public virtual void write(Writer* w)
Write the entire packet.
Throws: Interpreter::Exception

public virtual const string& toString()
Override the CCSDS head method since we don't need all those values.

public virtual CCSDSPacket* copy()
Return a pointer to an exact copy of this packet stored in completely different memory. Subclasses should override this method to copy secondary header data as well. This is basicly a virtual funtion wrapper around the copy constructor.

public virtual int samePlaceAs(CCSDSPacket* p)
This is the virtual funtion called by unique_comparator it returns true if two packets are not unique.

public friend int comes_before(CCSDSPacket* left, CCSDSPacket* right)
These are methods for comparing pointers for sorting and uniquing Useful if you have a STL container full of pointers to packets.

public friend int unique_comparator(CCSDSPacket* left, CCSDSPacket* right)
This function should be called when uniquing an STL container-full of pointers to packets. It is a wrapper for a virtual method.

public virtual int isAdjacentTo(CCSDSPacket* p)
Returns true if the sequence counters indicate the two packets are consecutive in a time sorted stream. Returns false if p==NULL;.

protected virtual
constant int extraHeadSize()
This class has no secondary header, but subclasses may add one by overriding these three methods.

protected virtual void readExtraHeaders(Reader* r)
Throws: Interpreter::Exception

protected virtual void writeExtraHeaders(Writer* w)
Throws: Interpreter::Exception

protected virtual
constant int trailerSize()
This class has no trailer, but subclasses may add one by overriding these three methods.

protected virtual void readTrailer(Reader* r)
Throws: Interpreter::Exception

protected virtual void writeTrailer(Writer* w)
Throws: Interpreter::Exception

protected virtual
constant int extraSize()
Extra header and trailer size combined.

protected virtual void initDataArray()
Set up the data array as being empty .

protected virtual
constant int sizeAccordingToHeader()
Return the data field size which is recorded in the primary header.

protected virtual void sizeAccordingToHeader(int size)
Set the data field size in the primary header this method is for internal use only since it does not ensure that the data array is large enough to hold this many bytes.

protected virtual void resizeDataArray(int size)
Resizes the data byte array to a specific size. Note this is for internal use only - it does not set the header length field.

private virtual void readBody(Reader* r)
Read the contents of the packet which follows the primary header. Note the primary header must be set (particularly the "length" field before this method can be called.
Throws: Interpreter: :Exception

Operators

public int CCSDSPacket& < const CCSDSPacket&
Ordering operator. Order packets by increasing sequence counter. Note that the sequence counter is cyclical, so this comparison does not make sense over a range of more than SEQUENCE_PERIOD/2 packets. This method correctly handles rollover.

Alphabetic Class Index | Class Inheritance Tree Index | Tool Index

Data Fields
public	static const int	SEQUENCE_PERIOD
public	static const int	SEQUENCE_HALF_PERIOD
public	static const int	MAX_LENGTH
private	unsigned char*	_data
private	int	array_size

Constructors / Destructor
protected	CCSDSPacket(const CCSDSPacket& orig) Copy constructor.
public	CCSDSPacket() Constructor - Creates a packet with zero data size. Note that by CCSDS rules a packet must have at least one data byte, so the size(int) method should be called before anything serious is done with the packet.
public	CCSDSPacket(int size) Constructor - Create a packet with a given number of data bytes.
public	~CCSDSPacket() Destructor - frees storage allocated for the data array.

Methods
public	virtual constant	unsigned char*	data()
public	virtual constant	int	size() Return the number of bytes in the data field.
public	virtual	void	size(int size) Resize the data field to a given number of bytes.
public	virtual constant	unsigned int	length()
public	virtual	void	length(unsigned int value) Override the CCSDSHeader versions of the length method to tie it to the data array size.
public	virtual	Reader*	dataReader() Return a pointer to a Reader object pointing to the data block of this packet. This is a new object which should be deleted when you are done with it.
public	virtual	Writer*	dataWriter() Return a pointer to a Reader object pointing to the data block of this packet. This is a new object which should be deleted when you are done with it.
public	virtual	int	minimumLength() Returns the minimum allowed value of the length field in the primary headewr for this type of packet. .
public	virtual	void	*read(const CCSDSHead& head, Reader r) Copy the given primary header into the packet and then read the rest of the packet. This method is useful if you want to read the packet in different ways depending on the APID. . Throws:** Interpreter::Exception
public	virtual	void	*read(Reader r) Read the entire packet. Throws:** Interpreter::Exception
public	virtual	void	*write(Writer w) Write the entire packet. Throws:** Interpreter::Exception
public	virtual	const string&	toString() Override the CCSDS head method since we don't need all those values.
public	virtual	CCSDSPacket*	copy() Return a pointer to an exact copy of this packet stored in completely different memory. Subclasses should override this method to copy secondary header data as well. This is basicly a virtual funtion wrapper around the copy constructor.
public	virtual	int	*samePlaceAs(CCSDSPacket p)** This is the virtual funtion called by unique_comparator it returns true if two packets are not unique.
public	friend	int	*comes_before(CCSDSPacket left, CCSDSPacket* right)** These are methods for comparing pointers for sorting and uniquing Useful if you have a STL container full of pointers to packets.
public	friend	int	*unique_comparator(CCSDSPacket left, CCSDSPacket* right)** This function should be called when uniquing an STL container-full of pointers to packets. It is a wrapper for a virtual method.
public	virtual	int	*isAdjacentTo(CCSDSPacket p)** Returns true if the sequence counters indicate the two packets are consecutive in a time sorted stream. Returns false if p==NULL;.
protected	virtual constant	int	extraHeadSize() This class has no secondary header, but subclasses may add one by overriding these three methods.
protected	virtual	void	*readExtraHeaders(Reader r) Throws:** Interpreter::Exception
protected	virtual	void	*writeExtraHeaders(Writer w) Throws:** Interpreter::Exception
protected	virtual constant	int	trailerSize() This class has no trailer, but subclasses may add one by overriding these three methods.
protected	virtual	void	*readTrailer(Reader r) Throws:** Interpreter::Exception
protected	virtual	void	*writeTrailer(Writer w) Throws:** Interpreter::Exception
protected	virtual constant	int	extraSize() Extra header and trailer size combined.
protected	virtual	void	initDataArray() Set up the data array as being empty .
protected	virtual constant	int	sizeAccordingToHeader() Return the data field size which is recorded in the primary header.
protected	virtual	void	sizeAccordingToHeader(int size) Set the data field size in the primary header this method is for internal use only since it does not ensure that the data array is large enough to hold this many bytes.
protected	virtual	void	resizeDataArray(int size) Resizes the data byte array to a specific size. Note this is for internal use only - it does not set the header length field.
private	virtual	void	*readBody(Reader r) Read the contents of the packet which follows the primary header. Note the primary header must be set (particularly the "length" field before this method can be called. Throws:** Interpreter: :Exception

Operators
public	int	CCSDSPacket& < const CCSDSPacket& Ordering operator. Order packets by increasing sequence counter. Note that the sequence counter is cyclical, so this comparison does not make sense over a range of more than SEQUENCE_PERIOD/2 packets. This method correctly handles rollover.