The VariableBuffer class implements a memory buffer for a single logged variable. More...

#include <var_buffer.h>

Collaboration diagram for XBot::VariableBuffer:

Classes
struct	BufferInfo

class	QueueImpl
	The QueueImpl class implements the buffering strategy for a single logged variable. More...

Public Types
enum	Mode { Mode::producer_consumer, Mode::circular_buffer }
	Enum for specifying the type of buffer. More...

typedef std::function< void(BufferInfo)>	CallbackType

Public Member Functions
	VariableBuffer (std::string name, int dim_rows, int dim_cols, int block_size)
	Constructor. More...

void	set_on_block_available (CallbackType callback)
	Sets a callback that is used to notify that a new block has been pushed into the queue. More...

void	set_buffer_mode (VariableBuffer::Mode mode)
	Set whether this buffer should be treated as a (possibly dual threaded) producer-consumer queue, or as a single-threaded circular buffer. More...

const std::string &	get_name () const

std::pair< int, int >	get_dimension () const

template<typename Derived >
bool	add_elem (const Eigen::MatrixBase< Derived > &data)
	Add an element to the buffer. More...

bool	read_block (Eigen::MatrixXd &data, int &valid_elements)
	Reads a whole block from the queue, if one is available. More...

bool	flush_to_queue ()
	Writes current block to the queue. More...

	~VariableBuffer ()

Static Public Member Functions
static int	NumBlocks ()

Detailed Description

The VariableBuffer class implements a memory buffer for a single logged variable.

This is an internal library component, and it is not meant for direct use.

The memory buffer is splitted into a fixed number of blocks, that make up a "pool" of available memory. When a block is full, it is pushed into a lockfree queue, so that it is available for the consumer thread. As soon as the block is consumed, it is returned back to the pool via another lockfree queue.

Apart from the lockfree queues, no other data is shared between add_elem() and read_block(). So, they can be called concurrently without further synchronization.

Because the lockfree queue is of the Single-Producer-Single-Consumer type, a single thread is allowed to call add_elem and read_block, concurrently.

Definition at line 32 of file var_buffer.h.

Member Typedef Documentation

typedef std::function<void(BufferInfo)> XBot::VariableBuffer::CallbackType

Definition at line 63 of file var_buffer.h.

Member Enumeration Documentation

enum XBot::VariableBuffer::Mode

strong

Enum for specifying the type of buffer.

Enumerator
producer_consumer
circular_buffer

Definition at line 40 of file var_buffer.h.

Constructor & Destructor Documentation

VariableBuffer::VariableBuffer	(	std::string	name,
		int	dim_rows,
		int	dim_cols,
		int	block_size
	)

Constructor.

Parameters

name	Variable name
dim_rows	Sample rows number
dim_cols	Sample columns number
block_size	Number of samples that make up a block

Definition at line 136 of file var_buffer.cpp.

VariableBuffer::~VariableBuffer ( )

Definition at line 272 of file var_buffer.cpp.

Member Function Documentation

template<typename Derived >

bool XBot::VariableBuffer::add_elem ( const Eigen::MatrixBase< Derived > & data )

inline

Add an element to the buffer.

If there is no space inside the current block, this is pushed into the queue by calling flush_to_queue().

Only a single producer thread is allowed to concurrently call this method.

Parameters

Derived	Data type
data	Data value

Returns: False if data could not be saved inside the buffer

Definition at line 260 of file var_buffer.h.

bool VariableBuffer::flush_to_queue ( )

Writes current block to the queue.

If a callback was registered through set_on_block_available(), it is called on success.

Returns: True on success (queue was not full)

Definition at line 196 of file var_buffer.cpp.

std::pair< int, int > VariableBuffer::get_dimension ( ) const

Definition at line 150 of file var_buffer.cpp.

const std::string & VariableBuffer::get_name ( ) const

Definition at line 42 of file matlogger2.cpp.

int VariableBuffer::NumBlocks ( )

static

Definition at line 261 of file var_buffer.cpp.

bool XBot::VariableBuffer::read_block	(	Eigen::MatrixXd &	data,
		int &	valid_elements
	)

Reads a whole block from the queue, if one is available.

The block is then returned to the pool.

Only a single consumer thread is allowed to concurrently call this method.

Parameters

data	Matrix which is filled with the read block (unless the function returns false)
valid_elements	Number of valid elements contained in the block. This means that only data.leftCols(valid_elements) contains valid data.

Returns: True if valid_elements > 0

Definition at line 165 of file var_buffer.cpp.

void XBot::VariableBuffer::set_buffer_mode ( VariableBuffer::Mode mode )

Set whether this buffer should be treated as a (possibly dual threaded) producer-consumer queue, or as a single-threaded circular buffer.

By default, the producer_consumer mode is used.

NOTE: only call this method before starting using the logger!!

Definition at line 266 of file var_buffer.cpp.

void VariableBuffer::set_on_block_available ( CallbackType callback )

Sets a callback that is used to notify that a new block has been pushed into the queue.

Definition at line 155 of file var_buffer.cpp.

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

/home/alaurenzi/Code/advr-superbuild/external/MatLogger2/include/matlogger2/utils/var_buffer.h
/home/alaurenzi/Code/advr-superbuild/external/MatLogger2/src/matlogger2.cpp
/home/alaurenzi/Code/advr-superbuild/external/MatLogger2/src/var_buffer.cpp

Classes

Public Types

Public Member Functions

Static Public Member Functions

Detailed Description

Member Typedef Documentation

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation