#include <ddtMemoryManager.hpp>

Inheritance diagram for ddt::DdtMemoryManager:

	DdtMemoryManager (DdtLogger *logger, const std::string broker_port)

virtual	~DdtMemoryManager ()

int32_t	CreateSharedMemory (const std::string data_stream_identifier, const int32_t max_data_sample_size, const int32_t number_of_samples)

bool	DeleteSharedMemory (const std::string data_stream_identifier)

bool	CheckIfShmExists (const std::string data_stream_identifier)

int32_t	get_max_data_sample_size (const std::string data_stream_identifier)

int32_t	get_number_of_samples (const std::string data_stream_identifier)

DdtMemoryAccessor *	get_memory_accessor (const std::string data_stream_identifier)

std::string	get_shm_id (const std::string data_stream_identifier) const

int32_t	GetMaxPossibleBufferSize (const int32_t max_data_sample_size)

bool	CheckSpaceAvailability (const int32_t max_data_sample_size, const int buffer_size)

const uint64_t	GetAvailableSpace ()

Detailed Description

This class manages the handling of shared memories.

Constructor & Destructor Documentation

◆ DdtMemoryManager()

DdtMemoryManager::DdtMemoryManager	(	DdtLogger *	logger,
		const std::string	broker_port
	)

Constructor

Parameters

logger	A DDT logger object (no transfer of ownership).
broker_port	The port from the broker. Will be part of the shm identifier.

◆ ~DdtMemoryManager()

DdtMemoryManager::~DdtMemoryManager ( )

virtualdefault

Destructor

Member Function Documentation

◆ CheckIfShmExists()

bool DdtMemoryManager::CheckIfShmExists ( const std::string data_stream_identifier )

Checks if the shared memory specified by data stream identifier already exists in the shm_map.

Parameters

data_stream_identifier The data stream identifier.

Returns: True if shared memory exists, false if not.

◆ CheckSpaceAvailability()

bool DdtMemoryManager::CheckSpaceAvailability	(	const int32_t	max_data_sample_size,
		const int	buffer_size
	)

protected

Checks if the requested space is available on the system.

Parameters

max_data_sample_size	The maximum data sample size.
buffer_size	Buffer size specified by the user.

Returns: True if the requested space is available, false if not.

◆ CreateSharedMemory()

int32_t DdtMemoryManager::CreateSharedMemory	(	const std::string	data_stream_identifier,
		const int32_t	max_data_sample_size,
		const int32_t	number_of_samples
	)

Creates a Boost shared memory object and constructs a circular buffer. For each shared memory an accessor is created.

Parameters

data_stream_identifier	The data stream identifier.
max_data_sample_size	The maximum data sample size.
number_of_samples	The Number of samples stored in the SHM ring buffer.

Return values

MEMORY_ERROR	Not enough memory.
-1	General error.
1	Success.

◆ DeleteSharedMemory()

bool DdtMemoryManager::DeleteSharedMemory ( const std::string data_stream_identifier )

Removes the shared memory and updates the shm map and the SharedMemories.txt file.

Parameters

data_stream_identifier The data stream identifier.

Returns: True if shared memory was successfully deleted, false if not.

◆ get_max_data_sample_size()

int32_t DdtMemoryManager::get_max_data_sample_size ( const std::string data_stream_identifier )

Returns max_data_sample_size.

Parameters

data_stream_identifier The data stream identifier.

Returns: The maximum data sample size.

◆ get_memory_accessor()

DdtMemoryAccessor * DdtMemoryManager::get_memory_accessor ( const std::string data_stream_identifier )

Returns memory_accessor.

Parameters

data_stream_identifier The data stream identifier.

Returns: The accessor to the shared memory.

◆ get_number_of_samples()

int32_t DdtMemoryManager::get_number_of_samples ( const std::string data_stream_identifier )

Returns number_of_samples.

Parameters

data_stream_identifier The data stream identifier.

Returns: The Number of samples stored in the SHM ring buffer.

◆ get_shm_id()

std::string DdtMemoryManager::get_shm_id ( const std::string data_stream_identifier ) const

Returns a string combination of port and data stream identifier which is the shm identifier.

Parameters

data_stream_identifier The data stream identifier.

Returns: The SHM identifier.

the shm id is created based on the data stream identifier and the port example: ddt-5001_ds1

◆ GetAvailableSpace()

const uint64_t DdtMemoryManager::GetAvailableSpace ( )

protected

Reads the available space on /dev/shm using the linux df command.

Returns: Available space in bytes.

create the linux command example: df /dev/shm | grep /dev/shm 2>&1

◆ GetMaxPossibleBufferSize()

int32_t DdtMemoryManager::GetMaxPossibleBufferSize ( const int32_t max_data_sample_size )

Computes the maximum possible number of buffer elements.

Parameters

max_data_sample_size The maximum data sample size.

Returns: The maximum possible number of buffer elements.

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

datatransfer/databrokerlib/src/include/ddt/ddtMemoryManager.hpp
datatransfer/databrokerlib/src/ddtMemoryManager.cpp