The channel observer object shall hold all samples for a channel. More...

#include <ichannelobserver.h>

Inheritance diagram for mdf::IChannelObserver:

Collaboration diagram for mdf::IChannelObserver:

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Public Member Functions
	IChannelObserver (const IDataGroup &dataGroup, const IChannel &channel)
	Constructor.

	~IChannelObserver () override=default
	Default destructor.

	IChannelObserver (const IChannelObserver &)=delete

	IChannelObserver (IChannelObserver &&)=delete

IChannelObserver &	operator= (const IChannelObserver &)=delete

IChannelObserver &	operator= (IChannelObserver &&)=delete

virtual uint64_t	NofSamples () const =0
	Returns number of samples.

std::string	Name () const
	Channel name.

std::string	Unit () const
	Channel unit.

const IChannel &	Channel () const
	Returns the channel object.

bool	IsMaster () const
	True if this is the master channel.

bool	IsArray () const
	True if this channel is an array channel.

std::vector< uint64_t >	Shape () const
	Returns a shape vector that describes an array dimension.

void	ReadVlsdData (bool read_vlsd_data)
	Property interface that defines if the VLSD raw data should be read or not.

bool	ReadVlsdData () const
	Returns the read VLSD bytes property.

uint64_t	ArraySize () const
	If this is an array channel, this function returns the array size.

template<typename V >
bool	GetChannelValue (uint64_t sample, V &value, uint64_t array_index=0) const
	Returns the channel value for a sample.

template<typename V >
std::vector< bool >	GetChannelSamples (std::vector< V > &values) const
	Simple function that returns all non-scaled samples.

template<typename V >
std::vector< bool >	GetChannelValues (uint64_t sample, std::vector< V > &values) const
	Returns a vector of array channel values for a specific sample.

template<typename V >
bool	GetEngValue (uint64_t sample, V &value, uint64_t array_index=0) const
	Returns the engineering value for a specific value.

template<typename V >
std::vector< bool >	GetEngSamples (std::vector< V > &values) const
	Simple function that returns all scaled samples.

template<typename V >
std::vector< bool >	GetEngValues (uint64_t sample, std::vector< V > &values) const
	Returns a vector of array values for a specific sample.

std::string	EngValueToString (uint64_t sample) const
	Support function that convert a sample value to a user friendly string.

const std::vector< uint64_t > &	GetOffsetList () const
	Returns the sample to VLSD offset list.

const std::vector< bool > &	GetValidList () const
	Returns the sample to valid list.

template<>
bool	GetChannelValue (uint64_t sample, std::string &value, uint64_t array_index) const
	Returns the sample channel value as a string.

template<>
bool	GetChannelValue (uint64_t sample, std::vector< uint8_t > &value, uint64_t array_index) const
	Returns the sample channel value as a byte array.

template<>
bool	GetEngValue (uint64_t sample, std::vector< uint8_t > &value, uint64_t array_index) const
	Returns the sample engineering (channel) value as a byte array.

Public Member Functions inherited from mdf::ISampleObserver
	ISampleObserver (const IDataGroup &data_group)
	Sample observer constructor.

virtual	~ISampleObserver ()
	Destructor.

virtual void	AttachObserver ()
	Attach the observer to an observer list (publisher).

virtual void	DetachObserver ()
	Detach the observer from an observer list.

virtual bool	OnSample (uint64_t sample, uint64_t record_id, const std::vector< uint8_t > &record)
	Observer function that receives the sample record and parse out a channel value.

bool	IsRecordIdNeeded (uint64_t record_id) const
	Function that test if this observer needs to read a specific record.

template<typename V >
bool	GetChannelValue (const IChannel &channel, uint64_t sample, const std::vector< uint8_t > &record, V &value, uint64_t array_index=0) const
	The function returns a channel value.

template<typename V >
bool	GetEngValue (const IChannel &channel, uint64_t sample, const std::vector< uint8_t > &record, V &value, uint64_t array_index=0) const
	Returns the scaled sample value for the channel with the record bytes as input. This function is mainly for internal use but is used together with sample observers.

Protected Member Functions
virtual bool	GetSampleUnsigned (uint64_t sample, uint64_t &value, uint64_t array_index) const =0
	Returns a unsigned sample value.

virtual bool	GetSampleSigned (uint64_t sample, int64_t &value, uint64_t array_index) const =0
	Returns a signed sample value.

virtual bool	GetSampleFloat (uint64_t sample, double &value, uint64_t array_index) const =0
	Returns a float sample value.

virtual bool	GetSampleText (uint64_t sample, std::string &value, uint64_t array_index) const =0
	Returns a string sample value.

virtual bool	GetSampleByteArray (uint64_t sample, std::vector< uint8_t > &value) const =0
	Returns a byte array sample value.

Protected Attributes
const IChannel &	channel_
	Reference to the channel (CN) block.

bool	read_vlsd_data_ = true
	Defines if the VLSD bytes should be read.

std::vector< uint64_t >	offset_list_
	Only used for VLSD channels.

std::vector< bool >	valid_list_
	List of valid samples.

Protected Attributes inherited from mdf::ISampleObserver
std::set< uint64_t >	record_id_list_
	List of subscribed channel groups.

const IDataGroup &	data_group_
	Reference to the data group (DG) block.

Additional Inherited Members
Public Attributes inherited from mdf::ISampleObserver
std::function< bool(uint64_t sample, uint64_t record_id, const std::vector< uint8_t > &record)>	DoOnSample
	Function object that is called if assigned.

Detailed Description

The main purpose for a channel observer is to store all channel samples for a channel. This object is used when reading data from a MDF file.

Member Function Documentation

◆ ArraySize()

uint64_t mdf::IChannelObserver::ArraySize ( ) const

nodiscard

Returns the array size if the channel is an array channel. The function returns 1 if not is an array channel.

Returns

◆ Channel()

const IChannel & mdf::IChannelObserver::Channel ( ) const

nodiscard

Returns the channel object associated with this observer. The channel is mostly needed to check if the channel is an array channel. Array channels are seldom used and are complex to handle.

Returns: Returns the channel object.

◆ EngValueToString()

std::string mdf::IChannelObserver::EngValueToString ( uint64_t sample ) const

nodiscard

Function that convert a sample to a user friendly string. For non-array samples, the function is the same as GetChannelValue but for array sample a JSON array string is returned.

Parameters

sample Sample index

Returns: JSON formatted string

◆ GetChannelSamples()

template<typename V >

std::vector< bool > mdf::IChannelObserver::GetChannelSamples ( std::vector< V > & values ) const

Returns all non-scaled sample values. Do not use this function for array channels. Use the GetChannelValues() function for array values.

Template Parameters

V	Type of values

Parameters

values The destination sample list.

Returns: Returns a list of valid booleans.

◆ GetChannelValue()

template<typename V >

bool mdf::IChannelObserver::GetChannelValue	(	uint64_t	sample,
		V &	value,
		uint64_t	array_index = 0 ) const

Returns the (unscaled) so-called channel value for a specific sample.

Template Parameters

V	Type of value

Parameters

sample	Sample number (0..).
value	The channel value.
array_index	Optional array index if the channel is an array.

Returns: True if value is valid.

◆ GetChannelValues()

template<typename V >

std::vector< bool > mdf::IChannelObserver::GetChannelValues	(	uint64_t	sample,
		std::vector< V > &	values ) const

The function is intended to be used on channel arrays. It returns all scaled array values for a sample. Note that the valid flags are return by the GetValidList() function.

The values vector doesn't need to be sized.

If used on non-array channels, it returns a vector of one values.

Template Parameters

V	Type of value

Parameters

sample	Sample index.
values	The destination vector of values.

Returns: Returns a vector of valid booleans.

◆ GetEngSamples()

template<typename V >

std::vector< bool > mdf::IChannelObserver::GetEngSamples ( std::vector< V > & values ) const

Returns all scaled sample values. Do not use this function for array channels. Use the GetChannelValues() function for array values.

Template Parameters

V	Type of values

Parameters

values The destination sample list.

Returns: Returns a list of valid booleans.

◆ GetEngValue()

template<typename V >

bool mdf::IChannelObserver::GetEngValue	(	uint64_t	sample,
		V &	value,
		uint64_t	array_index = 0 ) const

Returns the engineering (scaled) value for a specific value.

Template Parameters

V	Type of return value

Parameters

sample	Sample number (0..).
value	The return value.
array_index	Optional array index if the channel is an array.

Returns: True if the value is valid.

◆ GetEngValues()

template<typename V >

std::vector< bool > mdf::IChannelObserver::GetEngValues	(	uint64_t	sample,
		std::vector< V > &	values ) const

The function is intended to be used on channel arrays. It returns all scaled array values for a sample. Note that the valid flags are return by the GetValidList

If used on non-array channels, the value vector is of size 1.

Template Parameters

V	Type of value

Parameters

sample	Sample index.
values	List of returning array scaled values.

Returns: Returns a list of valid/invalid flags (boolean).

◆ GetOffsetList()

const std::vector< uint64_t > & mdf::IChannelObserver::GetOffsetList ( ) const

inlinenodiscard

This VLSD offset list is only needed when setting the ReadVLSDData() property to false. By only reading the offset list, the VLSD bytes can be read later as sample by sample or as a range of VSLD bytes. THis read saves primary memory and is much faster if only some samples are needed.

Returns

◆ ReadVlsdData()

void mdf::IChannelObserver::ReadVlsdData ( bool read_vlsd_data )

Reading VLSD raw data may fail if there is no room for the bytes in the primary memory. Normally is this property normally set to true but if set to false, only the offset into the VLSD block is read. This call should be followed buy one or more call to the MdfWriter::ReadVlsdData() function. By this, only partial samples can be read in and thus saving primary memory.

Parameters

read_vlsd_data Set to false if VLSD bytes shouldn't be read.

◆ Shape()

std::vector< uint64_t > mdf::IChannelObserver::Shape ( ) const

nodiscard

This function is used to size an array in an external library. The Eigen and XTensor C++ libraries are typical

Returns: Shape vector that describes an array dimension.

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

include/mdf/ichannelobserver.h

Public Member Functions

Protected Member Functions

Protected Attributes

Additional Inherited Members

Detailed Description

Member Function Documentation

◆ ArraySize()

◆ Channel()

◆ EngValueToString()

◆ GetChannelSamples()

◆ GetChannelValue()

◆ GetChannelValues()

◆ GetEngSamples()

◆ GetEngValue()

◆ GetEngValues()

◆ GetOffsetList()

◆ ReadVlsdData()

◆ Shape()