A scanner of sample data. More...

#include <SampleScanner.h>

Inheritance diagram for nidas::core::SampleScanner:

Public Member Functions
	SampleScanner (int bufsize=8192)

virtual	~SampleScanner ()

virtual void	init ()
	Initialize the scanner. More...

virtual void	setMessageParameters (unsigned int len, const std::string &val, bool eom)=0 throw (nidas::util::InvalidParameterException)
	Set the parameters associated with scanning of character messages. More...

virtual const std::string &	getMessageSeparator () const
	Returns an empty string. More...

virtual const std::string	getBackslashedMessageSeparator () const
	Returns an empty string. More...

virtual bool	getMessageSeparatorAtEOM () const

virtual unsigned int	getMessageLength () const
	Returns 0. More...

virtual bool	getNullTerminate () const
	Should the SampleScanner append a null character, '\0', to the messages. More...

void	setUsecsPerByte (int val)

int	getUsecsPerByte () const

virtual size_t	readBuffer (DSMSensor *sensor, bool &exhausted) throw (nidas::util::IOException)
	Read from the sensor into the internal buffer of this SampleScanner. More...

virtual size_t	readBuffer (DSMSensor *sensor, bool &exhausted, int msecTimeout) throw (nidas::util::IOException)
	Read from the sensor into the internal buffer of this SampleScanner, providing a timeout in milliseconds. More...

virtual void	clearBuffer ()

virtual Sample *	nextSample (DSMSensor *sensor)=0
	Extract the next sample from the buffer. More...

unsigned int	getBytesInBuffer () const

virtual void	resetStatistics ()

virtual void	calcStatistics (unsigned int periodUsec)
	Update the sensor sampling statistics: samples/sec, bytes/sec, min/max sample size, that can be accessed via getObservedSamplingRate(), getObservedDataRate() etc. More...

unsigned int	getMaxSampleLength () const

unsigned int	getMinSampleLength () const

unsigned int	getBadTimeTagCount () const

float	getObservedSamplingRate () const

float	getObservedDataRate () const

void	addNumBytesToStats (size_t val)

void	addSampleToStats (unsigned int val)

void	incrementBadTimeTags ()

Protected Attributes
const unsigned int	BUFSIZE
	Buffer size for reading from sensor. More...

char *	_buffer

unsigned int	_bufhead

unsigned int	_buftail

Sample *	_osamp

struct dsm_sample	_header

unsigned int	_outSampRead

unsigned int	_outSampToRead

char *	_outSampDataPtr

std::string	_messageSeparator

int	_messageLength

bool	_separatorAtEOM

char *	_separator
	messageSeparator in a C string. More...

int	_separatorLen
	Length of messageSeparator. More...

Private Member Functions
	SampleScanner (const SampleScanner &)
	No copy (could be added if needed). More...

SampleScanner &	operator= (const SampleScanner &)
	No assignment (could be added if needed). More...

Private Attributes
std::string	_emptyString

time_t	_initialTimeSecs

unsigned int	_minSampleLength [2]

unsigned int	_maxSampleLength [2]

int	_currentIndex

int	_reportIndex

size_t	_nsamples

size_t	_nbytes

unsigned int	_badTimeTags

float	_sampleRateObs
	Observed number of samples per second. More...

float	_dataRateObs

int	_usecsPerByte

Detailed Description

A scanner of sample data.

Provides a readBuffer() method to read data from a DSMSensor into an internal buffer. Then defines a virtual nextSample() method to extract all available samples from that buffer.

Currently there are four implementations of SampleScanner, which differ in how they extract samples from the internal buffer:

DriverSampleScanner: A SampleScanner for reading samples that have been pre-formatted by a device driver - they already have a header consisting of a timetag, and a data length. This can be used, for example, to read samples from a driver supporting an A/D converter.

MessageSampleScanner: Subclass of DriverSampleScanner, supporting the set/get of the message separation parameters. This scanner does not itself break the input into samples, since this has been done by the driver module.

MessageStreamScanner: Provides sets and gets of message separation parameters used in parsing input messages from a sensor. Parses the stream input, breaking it into samples, by recognizing separators in the message stream.

DatagramSampleScanner: Creates samples from input datagrams, a simple task since the OS maintains the separation of the input datagrams. Each datagram becomes a separate sample, with a timetag taken from the system clock at the time the scanner has determined that there is data available.

Constructor & Destructor Documentation

SampleScanner::SampleScanner ( int bufsize = 8192 )

References resetStatistics().

SampleScanner::~SampleScanner ( )

virtual

References _buffer, _osamp, _separator, and nidas::core::Sample::freeReference().

nidas::core::SampleScanner::SampleScanner ( const SampleScanner & )

private

No copy (could be added if needed).

Member Function Documentation

void nidas::core::SampleScanner::addNumBytesToStats ( size_t val )

inline

References _nbytes.

void nidas::core::SampleScanner::addSampleToStats ( unsigned int val )

inline

References _currentIndex, _maxSampleLength, _minSampleLength, and _nsamples.

Referenced by nidas::core::DriverSampleScanner::nextSample(), nidas::core::DatagramSampleScanner::nextSample(), nidas::core::MessageStreamScanner::nextSampleByLength(), nidas::core::MessageStreamScanner::nextSampleSepBOM(), nidas::core::MessageStreamScanner::nextSampleSepEOM(), and nidas::core::MessageStreamScanner::requestBiggerSample().

void SampleScanner::calcStatistics ( unsigned int periodUsec )

virtual

Update the sensor sampling statistics: samples/sec, bytes/sec, min/max sample size, that can be accessed via getObservedSamplingRate(), getObservedDataRate() etc.

Should be called every periodUsec by a user of this sensor.

Parameters

periodUsec Statistics period.

References _currentIndex, _dataRateObs, _maxSampleLength, _minSampleLength, _nbytes, _nsamples, _reportIndex, _sampleRateObs, and USECS_PER_SEC.

Referenced by nidas::core::DSMSensor::calcStatistics().

void SampleScanner::clearBuffer ( )

virtual

References _bufhead, and _buftail.

Referenced by nidas::core::DSMSensor::clearBuffer().

virtual const std::string nidas::core::SampleScanner::getBackslashedMessageSeparator ( ) const

inlinevirtual

Returns an empty string.

Reimplemented in nidas::core::MessageStreamScanner, and nidas::core::MessageSampleScanner.

References _emptyString.

unsigned int nidas::core::SampleScanner::getBadTimeTagCount ( ) const

inline

References _badTimeTags.

Referenced by nidas::core::DSMSensor::getBadTimeTagCount().

unsigned int nidas::core::SampleScanner::getBytesInBuffer ( ) const

inline

References _bufhead, and _buftail.

unsigned int nidas::core::SampleScanner::getMaxSampleLength ( ) const

inline

References _maxSampleLength, and _reportIndex.

Referenced by nidas::core::DSMSensor::getMaxSampleLength().

virtual unsigned int nidas::core::SampleScanner::getMessageLength ( ) const

inlinevirtual

Returns 0.

Reimplemented in nidas::core::MessageStreamScanner, and nidas::core::MessageSampleScanner.

virtual const std::string& nidas::core::SampleScanner::getMessageSeparator ( ) const

inlinevirtual

Returns an empty string.

Reimplemented in nidas::core::MessageStreamScanner, and nidas::core::MessageSampleScanner.

References _emptyString.

virtual bool nidas::core::SampleScanner::getMessageSeparatorAtEOM ( ) const

inlinevirtual

Reimplemented in nidas::core::MessageStreamScanner, and nidas::core::MessageSampleScanner.

unsigned int nidas::core::SampleScanner::getMinSampleLength ( ) const

inline

References _maxSampleLength, _minSampleLength, and _reportIndex.

Referenced by nidas::core::DSMSensor::getMinSampleLength().

virtual bool nidas::core::SampleScanner::getNullTerminate ( ) const

inlinevirtual

Should the SampleScanner append a null character, '\0', to the messages.

Reimplemented in nidas::core::DatagramSampleScanner, and nidas::core::MessageStreamScanner.

Referenced by nidas::core::CharacterSensor::getNullTerminated().

float SampleScanner::getObservedDataRate ( ) const

References _currentIndex, _dataRateObs, _initialTimeSecs, _nbytes, and _reportIndex.

Referenced by nidas::core::DSMSensor::getObservedDataRate().

float SampleScanner::getObservedSamplingRate ( ) const

References _currentIndex, _initialTimeSecs, _nsamples, _reportIndex, and _sampleRateObs.

Referenced by nidas::core::DSMSensor::getObservedSamplingRate().

int nidas::core::SampleScanner::getUsecsPerByte ( ) const

inline

References _usecsPerByte.

Referenced by nidas::core::MessageStreamScanner::nextSampleByLength(), nidas::core::MessageStreamScanner::nextSampleSepBOM(), and nidas::core::MessageStreamScanner::nextSampleSepEOM().

void nidas::core::SampleScanner::incrementBadTimeTags ( )

inline

References _badTimeTags.

Referenced by nidas::core::DriverSampleScanner::nextSample().

void SampleScanner::init ( )

virtual

Initialize the scanner.

Must be called by a user of SampleScanner prior to calling readSamples().

References resetStatistics().

virtual Sample* nidas::core::SampleScanner::nextSample ( DSMSensor * sensor )

pure virtual

Extract the next sample from the buffer.

Returns NULL if there are no more samples in the buffer.

Implemented in nidas::core::DatagramSampleScanner, nidas::core::MessageStreamScanner, and nidas::core::DriverSampleScanner.

Referenced by nidas::core::DSMSensor::nextSample().

SampleScanner& nidas::core::SampleScanner::operator= ( const SampleScanner & )

private

No assignment (could be added if needed).

size_t SampleScanner::readBuffer	(	DSMSensor *	sensor,
		bool &	exhausted
	)
throw	(	nidas::util::IOException
	)

virtual

Read from the sensor into the internal buffer of this SampleScanner.

Reimplemented in nidas::core::DatagramSampleScanner, and nidas::core::MessageStreamScanner.

References DLOG, nidas::core::Project::getInstance(), and len.

Referenced by readBuffer(), nidas::core::MessageStreamScanner::readBuffer(), and nidas::core::DSMSensor::readBuffer().

size_t SampleScanner::readBuffer	(	DSMSensor *	sensor,
		bool &	exhausted,
		int	msecTimeout
	)
throw	(	nidas::util::IOException
	)

virtual

Read from the sensor into the internal buffer of this SampleScanner, providing a timeout in milliseconds.

This will throw nidas::util::IOTimeoutException if the read fails due to a timeout.

Reimplemented in nidas::core::MessageStreamScanner.

References MSECS_PER_SEC, NLOG, NSECS_PER_MSEC, and readBuffer().

void SampleScanner::resetStatistics ( )

virtual

References _badTimeTags, _currentIndex, _dataRateObs, _initialTimeSecs, _maxSampleLength, _minSampleLength, _nbytes, _nsamples, _reportIndex, and _sampleRateObs.

Referenced by init(), and SampleScanner().

virtual void nidas::core::SampleScanner::setMessageParameters	(	unsigned int	len,
		const std::string &	val,
		bool	eom
	)
throw	(	nidas::util::InvalidParameterException
	)