A DriverSampleScanner which supports the set/get of message separation parameters. More...

#include <SampleScanner.h>

Inheritance diagram for nidas::core::MessageSampleScanner:

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Public Member Functions
	MessageSampleScanner (int bufsize=8192)

void	setMessageParameters (unsigned int len, const std::string &val, bool eom)
	Set the parameters which delineate a message for this scanner.

const std::string &	getMessageSeparator () const
	Get message separator string.

const std::string	getBackslashedMessageSeparator () const
	Get message separator with backslash sequences added back.

bool	getMessageSeparatorAtEOM () const
	Is the message separator at the end of the message (true), or at the beginning (false)?

unsigned int	getMessageLength () const
	Returns 0.

Sample *	nextSample (DSMSensor *sensor)
	Extract the next sample from the buffer.

virtual void	init ()
	Initialize the scanner.

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

void	setUsecsPerByte (int val)

int	getUsecsPerByte () const

virtual size_t	readBuffer (DSMSensor *sensor, bool &exhausted)
	Read from the sensor into the internal buffer of this SampleScanner.

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

virtual void	clearBuffer ()

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.

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.

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.

int	_separatorLen
	Length of messageSeparator.

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.

float	_dataRateObs

int	_usecsPerByte

Detailed Description

A DriverSampleScanner which supports the set/get of message separation parameters.

Typically these parameters are sent down to a driver module by an implementation of DSMSensor.

Constructor & Destructor Documentation

◆ MessageSampleScanner()

MessageSampleScanner::MessageSampleScanner ( int bufsize = 8192 )

Member Function Documentation

◆ addNumBytesToStats()

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

inlineinherited

References nidas::core::SampleScanner::_nbytes, and nidas::core::getSample().

Referenced by nidas::core::SampleScanner::readBuffer(), and nidas::core::DatagramSampleScanner::readBuffer().

◆ addSampleToStats()

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

inlineinherited

References nidas::core::SampleScanner::_currentIndex, nidas::core::SampleScanner::_maxSampleLength, nidas::core::SampleScanner::_minSampleLength, and nidas::core::SampleScanner::_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().

◆ calcStatistics()

void SampleScanner::calcStatistics ( unsigned int periodUsec )

virtualinherited

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 nidas::core::SampleScanner::_currentIndex, nidas::core::SampleScanner::_dataRateObs, nidas::core::SampleScanner::_maxSampleLength, nidas::core::SampleScanner::_minSampleLength, nidas::core::SampleScanner::_nbytes, nidas::core::SampleScanner::_nsamples, nidas::core::SampleScanner::_reportIndex, nidas::core::SampleScanner::_sampleRateObs, nidas::core::getSample(), and USECS_PER_SEC.

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

◆ clearBuffer()

void SampleScanner::clearBuffer ( )

virtualinherited

References nidas::core::SampleScanner::_bufhead, and nidas::core::SampleScanner::_buftail.

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

◆ getBackslashedMessageSeparator()

const string MessageSampleScanner::getBackslashedMessageSeparator ( ) const

virtual

Get message separator with backslash sequences added back.

Reimplemented from nidas::core::SampleScanner.

References nidas::core::SampleScanner::_messageSeparator, and nidas::util::addBackslashSequences().

◆ getBadTimeTagCount()

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

inlineinherited

References nidas::core::SampleScanner::_badTimeTags.

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

◆ getBytesInBuffer()

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

inlineinherited

References nidas::core::SampleScanner::_bufhead, and nidas::core::SampleScanner::_buftail.

◆ getMaxSampleLength()

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

inlineinherited

References nidas::core::SampleScanner::_maxSampleLength, and nidas::core::SampleScanner::_reportIndex.

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

◆ getMessageLength()

unsigned int nidas::core::MessageSampleScanner::getMessageLength ( ) const

inlinevirtual

Returns 0.

Reimplemented from nidas::core::SampleScanner.

References nidas::core::SampleScanner::_messageLength.

◆ getMessageSeparator()

const std::string & nidas::core::MessageSampleScanner::getMessageSeparator ( ) const

inlinevirtual

Get message separator string.

Any backslash sequences will have been replaced by their intended value.

Reimplemented from nidas::core::SampleScanner.

References nidas::core::SampleScanner::_messageSeparator.

◆ getMessageSeparatorAtEOM()

bool nidas::core::MessageSampleScanner::getMessageSeparatorAtEOM ( ) const

inlinevirtual

Is the message separator at the end of the message (true), or at the beginning (false)?

Reimplemented from nidas::core::SampleScanner.

References nidas::core::SampleScanner::_separatorAtEOM.

◆ getMinSampleLength()

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

inlineinherited

References nidas::core::SampleScanner::_maxSampleLength, nidas::core::SampleScanner::_minSampleLength, and nidas::core::SampleScanner::_reportIndex.

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

◆ getNullTerminate()

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

inlinevirtualinherited

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

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

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

◆ getObservedDataRate()

float SampleScanner::getObservedDataRate ( ) const

inherited

References nidas::core::SampleScanner::_currentIndex, nidas::core::SampleScanner::_dataRateObs, nidas::core::SampleScanner::_initialTimeSecs, nidas::core::SampleScanner::_nbytes, and nidas::core::SampleScanner::_reportIndex.

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

◆ getObservedSamplingRate()

float SampleScanner::getObservedSamplingRate ( ) const

inherited

References nidas::core::SampleScanner::_currentIndex, nidas::core::SampleScanner::_initialTimeSecs, nidas::core::SampleScanner::_nsamples, nidas::core::SampleScanner::_reportIndex, and nidas::core::SampleScanner::_sampleRateObs.

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

◆ getUsecsPerByte()

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

inlineinherited

References nidas::core::SampleScanner::_usecsPerByte.

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

◆ incrementBadTimeTags()

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

inlineinherited

References nidas::core::SampleScanner::_badTimeTags.

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

◆ init()

void SampleScanner::init ( )

virtualinherited

Initialize the scanner.

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

References nidas::core::SampleScanner::resetStatistics().

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

◆ nextSample()

Sample * DriverSampleScanner::nextSample ( DSMSensor * sensor )

virtualinherited

Extract the next sample from the buffer.

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

Implements nidas::core::SampleScanner.

◆ readBuffer() [1/2]

size_t SampleScanner::readBuffer	(	DSMSensor *	sensor,
		bool &	exhausted )

virtualinherited

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

Exceptions

nidas::util::IOException

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

References nidas::core::SampleScanner::_buffer, nidas::core::SampleScanner::_bufhead, nidas::core::SampleScanner::_buftail, nidas::core::SampleScanner::addNumBytesToStats(), nidas::core::SampleScanner::BUFSIZE, DLOG, nidas::core::DSMSensor::getDSMId(), nidas::core::Project::getInstance(), nidas::core::DSMSensor::getName(), nidas::core::getSample(), nidas::core::DSMSensor::getSensorId(), len, and nidas::core::DSMSensor::read().

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

◆ readBuffer() [2/2]

size_t SampleScanner::readBuffer	(	DSMSensor *	sensor,
		bool &	exhausted,
		int	msecTimeout )

virtualinherited

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.

Exceptions

nidas::util::IOException

Reimplemented in nidas::core::MessageStreamScanner.

References nidas::core::DSMSensor::getName(), nidas::core::DSMSensor::getReadFd(), nidas::core::getSample(), MSECS_PER_SEC, NLOG, NSECS_PER_MSEC, and nidas::core::SampleScanner::readBuffer().

◆ resetStatistics()

void SampleScanner::resetStatistics ( )

virtualinherited

References nidas::core::SampleScanner::_badTimeTags, nidas::core::SampleScanner::_currentIndex, nidas::core::SampleScanner::_dataRateObs, nidas::core::SampleScanner::_initialTimeSecs, nidas::core::SampleScanner::_maxSampleLength, nidas::core::SampleScanner::_minSampleLength, nidas::core::SampleScanner::_nbytes, nidas::core::SampleScanner::_nsamples, nidas::core::SampleScanner::_reportIndex, nidas::core::SampleScanner::_sampleRateObs, and nidas::core::getSample().

Referenced by nidas::core::SampleScanner::init(), and nidas::core::SampleScanner::SampleScanner().

◆ setMessageParameters()

void MessageSampleScanner::setMessageParameters	(	unsigned int	len,
		const std::string &	val,
		bool	eom )

virtual

Set the parameters which delineate a message for this scanner.

The messageSeparator is the string of bytes that a sensor outputs between messages. The string may contain baskslash sequences.

Parameters

len The message length in bytes. A value of zero means the message length is completely variable, and that a scanner is should always be looking for a messageSeparator in the data. A positive value means read in messageLength number of bytes and then start looking for the messageSeparator. The messageLength does not include the length of the messageSeparator.

Setting a positive message length is only necessary if there is a chance that the message separator could be found in the data portion of the message. This may be the case if the sensor is generating binary data. A positive message length causes the parser to read messageLength number of bytes before again searching for the separator. This also makes the parsing a bit more efficient. If the messageLength is too small it will not necessarily cause messages to be truncated - all the data up to, and including the separator is still read and passed along for processing. If the value is larger than the actual message length it will cause two or more messages to be concatenated into one.

Parameters

eom True means the message scanner expects the separator at the end of the message, and the next byte read after the separator is the first byte of the next message. The timetag of a sample is the receipt time of the first byte after the separator of the previous message. False means the scanner expects the separator at the beginning of the message, in which case the timetag of a sample is the receipt time of the first byte of the messageSeparator.