TGeoposition Class Reference

List of all members.

Signals
void	newPosition (void)
	Signal emmited when a valid position is received.
Public Member Functions
	TGeoposition (void)
	Class constructor and no more.
bool	openConnection (const char *port_name)
	Opens a serial port where it is supossed that the GPS is attached.
void	closeConnection (void)
	Closes the serial port ... if it is open.
void	sendStr (const char *cad)
	Sends strings of text to the device.
void	sendData (const char *dat, int len)
	Sends a given number of to the device.
int	receiveData (char *destination, int max_data)
	Receives the data that the devices sends to the host.
void	processReceivedData (void)
	Handles the received data from the device.
bool	findMessage (const char data, unsigned int size, unsigned int start, unsigned int *length)
	Finds messages in the stream of data received from the device.
bool	parseMessage (const char *start, unsigned int length)
	Parses the content of the messages.
void	getLastPosition (double utc_t, double longit, Tcardinaleixos c_longitude, double latit, Tcardinaleixos *c_latitude)
	Returns the last valid GPS position received.
	~TGeoposition (void)
	Class destructor.

Constructor & Destructor Documentation

TGeoposition::~TGeoposition ( void )

Class destructor.

It is important to call it in order to free locked resources.

Member Function Documentation

void TGeoposition::closeConnection ( void )

Closes the serial port ... if it is open.

Example:

      geo->closeConnection();

bool TGeoposition::findMessage	(	const char *	data,
		unsigned int	size,
		unsigned int *	start,
		unsigned int *	length
	)

Finds messages in the stream of data received from the device.

This functions is responsible for finding message items in the strem of data.

Attention:: Take into account that messages could be corrupted, this function is not responsible for this task, it only says that the message is here!!!!!

Parameters:

	data	data buffer to be explored
	size	number of bytes to be considered
`[out]`	start	index of the start of the found message
`[out]`	length	length of found the message

Returns:: true if message found; false if nothing found

Example:


     Altre dia sera.

void TGeoposition::getLastPosition	(	double *	utc_t,
		double *	longit,
		Tcardinaleixos *	c_longitude,
		double *	latit,
		Tcardinaleixos *	c_latitude
	)

Returns the last valid GPS position received.

Parameters:

`[out]`	utc_t	UTC time
`[out]`	longit	longitude
`[out]`	c_longitude	`EAST` or `WEST`
`[out]`	latit	latitude
`[out]`	c_latitude	`NOTH` or `SOUTH`

bool TGeoposition::openConnection ( const char * port_name )

Opens a serial port where it is supossed that the GPS is attached.

Parameters:

port_name

name of the device that provides access to a given serial port

Return values:

	true	if port succesfully openned
	false	if port can not be openned

Example:

      TGeoposition geo = new TGeoposition();

      if (geo->openConnection("COM1")) {
            printf("Port openned.");
      } else {
            printf("Error openning the port");
      }

bool TGeoposition::parseMessage	(	const char *	data,
		unsigned int	length
	)

Parses the content of the messages.

In this case, this function analyses this NMEA-0183 command $GPGGA (Global Positioning System Fix Data) i.e. $GPGGA,170834,4124.8963,N,08151.6838,W,1,05,1.5,280.2,M,-34.0,M,,,*75 see http://home.mira.net/~gnb/gps/nmea.html#gpgga

Parameters:

	data	pointer to data
	length	length of the message

Returns:: true if a valid message has been parsed; false if message is not the expected one

Example:


     Altre dia sera.

void TGeoposition::processReceivedData ( void )

Handles the received data from the device.

This functions is responsible of managing an input buffer for data from the device and calling functions for analyse data It should be called periodically of using some event-driven mechanism in order to process data.

Example:

      timer = new QTimer();

      connect(timer,SIGNAL(timeout),geo,SLOT(processReceivedData());
      timer->setInterval(1000);
      timer->start();

int TGeoposition::receiveData	(	char *	destination,
		int	max_data
	)

Receives the data that the devices sends to the host.

This functions is non-blocking, so it returns inmediately and no waits if data is not available

Parameters:

	destination	pointer where data buyes will be put
	max_data	maximum number of bytes that can be received, remaing data is keept in device's buffer

Returns:: number of received bytes, or 0 if nothing received

Example:

      unsigned char buffer[10000];
      int num_bytes;

      num_bytes = geo->receiveData(buffer, 10000);
      if (num_bytes > 0) {
            printf("Received %d byes\n", num_bytes);
      }

void TGeoposition::sendData	(	const char *	dat,
		int	len
	)

Sends a given number of to the device.

This functions is non-blocking, so it returns inmediately and no waits until data is sent to the device

Parameters:

	dat	pointer to data
	len	number of bytes to be sent

Example:

      unsigned char dades[] = {35,49,110,69};

      geo->sendData(dades, 4);

void TGeoposition::sendStr ( const char * cad )

Sends strings of text to the device.

This functions is non-blocking, so it returns inmediately and no waits until data is sent to the device

Parameters:

cad

pointer to a null-terminated standard C string

Example:

      geo->sendStr("Les coques amb tomaca estan molt bones\x0D");

The documentation for this class was generated from the following files:

/home/aperles/dades/asignatures/dsii/Qt/visor_GPS/src/tgeoposition.h
/home/aperles/dades/asignatures/dsii/Qt/visor_GPS/src/moc_tgeoposition.cpp
/home/aperles/dades/asignatures/dsii/Qt/visor_GPS/src/tgeoposition.cpp

TGeoposition Class Reference

Signals

Public Member Functions

Constructor & Destructor Documentation

Member Function Documentation