iox::concurrent::LockFreeQueue< ElementType, Capacity > Class Template Reference

implements a lock free queue (i.e. container with FIFO order) of elements of type T with a fixed Capacity More...

#include <iceoryx_hoofs/concurrent/lockfree_queue.hpp>

Public Types
using	element_t = ElementType

Public Member Functions
	LockFreeQueue () noexcept
	creates and initalizes an empty LockFreeQueue
	LockFreeQueue (const LockFreeQueue &)=delete
	LockFreeQueue (LockFreeQueue &&)=delete
LockFreeQueue &	operator= (const LockFreeQueue &)=delete
LockFreeQueue &	operator= (LockFreeQueue &&)=delete
constexpr uint64_t	capacity () const noexcept
	returns the capacity of the queue
bool	tryPush (ElementType &&value) noexcept
	tries to insert value in FIFO order, moves the value internally
bool	tryPush (const ElementType &value) noexcept
	tries to insert value in FIFO order, copies the value internally
iox::cxx::optional< ElementType >	push (const ElementType &value) noexcept
	inserts value in FIFO order, always succeeds by removing the oldest value when the queue is detected to be full (overflow)
iox::cxx::optional< ElementType >	push (ElementType &&value) noexcept
	inserts value in FIFO order, always succeeds by removing the oldest value when the queue is detected to be full (overflow)
iox::cxx::optional< ElementType >	pop () noexcept
	tries to remove value in FIFO order
bool	empty () const noexcept
	check whether the queue is empty
uint64_t	size () const noexcept
	get the number of stored elements in the queue

Protected Types
using	Queue = IndexQueue<Capacity>
using	BufferIndex = typename Queue::value_t

Protected Member Functions
template<typename T>
void	writeBufferAt (const BufferIndex &, T &&) noexcept
template<typename T>
iox::cxx::optional< ElementType >	pushImpl (T &&value) noexcept
cxx::optional< ElementType >	readBufferAt (const BufferIndex &) noexcept

Protected Attributes
Queue	m_freeIndices
Queue	m_usedIndices
Buffer< ElementType, Capacity, BufferIndex >	m_buffer
std::atomic< uint64_t >	m_size {0u}

Detailed Description

template<typename ElementType, uint64_t Capacity>
class iox::concurrent::LockFreeQueue< ElementType, Capacity >

implements a lock free queue (i.e. container with FIFO order) of elements of type T with a fixed Capacity

Member Function Documentation

capacity()

template<typename ElementType, uint64_t Capacity>

uint64_t iox::concurrent::LockFreeQueue< ElementType, Capacity >::capacity ( ) const

constexprnoexcept

returns the capacity of the queue

Note

threadsafe, lockfree

empty()

template<typename ElementType, uint64_t Capacity>

bool iox::concurrent::LockFreeQueue< ElementType, Capacity >::empty ( ) const

noexcept

check whether the queue is empty

Returns

true iff the queue is empty

Note

that if the queue is used concurrently it might not be empty anymore after the call (but it was at some point during the call)

threadsafe, lockfree

pop()

template<typename ElementType, uint64_t Capacity>

iox::cxx::optional< ElementType > iox::concurrent::LockFreeQueue< ElementType, Capacity >::pop ( )

noexcept

tries to remove value in FIFO order

Returns

value if removal was successful, empty optional otherwise

Note

threadsafe, lockfree

push() [1/2]

template<typename ElementType, uint64_t Capacity>

iox::cxx::optional< ElementType > iox::concurrent::LockFreeQueue< ElementType, Capacity >::push ( const ElementType & value )

noexcept

inserts value in FIFO order, always succeeds by removing the oldest value when the queue is detected to be full (overflow)

Parameters

value

to be inserted is copied into the queue

Returns

removed value if an overflow occured, empty optional otherwise

Note

threadsafe, lockfree

push() [2/2]

template<typename ElementType, uint64_t Capacity>

iox::cxx::optional< ElementType > iox::concurrent::LockFreeQueue< ElementType, Capacity >::push ( ElementType && value )

noexcept

inserts value in FIFO order, always succeeds by removing the oldest value when the queue is detected to be full (overflow)

Parameters

value

to be inserted is moved into the queue if possible

Returns

removed value if an overflow occured, empty optional otherwise

Note

threadsafe, lockfree

size()

template<typename ElementType, uint64_t Capacity>

uint64_t iox::concurrent::LockFreeQueue< ElementType, Capacity >::size ( ) const

noexcept

get the number of stored elements in the queue

Returns

number of stored elements in the queue

Note

that this will not be perfectly in sync with the actual number of contained elements during concurrent operation but will always be at most capacity

threadsafe, lockfree

tryPush() [1/2]

template<typename ElementType, uint64_t Capacity>

bool iox::concurrent::LockFreeQueue< ElementType, Capacity >::tryPush ( const ElementType & value )

noexcept

tries to insert value in FIFO order, copies the value internally

Parameters

value

to be inserted

Returns

true if insertion was successful (i.e. queue was not full during push), false otherwise

Note

threadsafe, lockfree

tryPush() [2/2]

template<typename ElementType, uint64_t Capacity>

bool iox::concurrent::LockFreeQueue< ElementType, Capacity >::tryPush ( ElementType && value )

noexcept

tries to insert value in FIFO order, moves the value internally

Parameters

value

to be inserted

Returns

true if insertion was successful (i.e. queue was not full during push), false otherwise

Note

threadsafe, lockfree

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

• iceoryx_hoofs/concurrent/lockfree_queue.hpp