iox::concurrent::ResizeableLockFreeQueue🔗
implements a lock free queue (i.e. container with FIFO order) of elements of type T with a maximum capacity MaxCapacity. The capacity can be defined to be anything between 0 and MaxCapacity at construction time or later at runtime using setCapacity. This is even possible while concurrent push and pop operations are executed, i.e. the queue does not have to be empty. Only one thread will succeed setting its desired capacity if there are more threads trying to change the capacity at the same time (it is unpredictable which thread). More...
#include <iceoryx_hoofs/concurrent/resizeable_lockfree_queue.hpp>
Inherits from iox::concurrent::LockFreeQueue< ElementType, MaxCapacity >
Public Types🔗
| Name | |
|---|---|
| using ElementType | element_t |
Public Functions🔗
| Name | |
|---|---|
| ResizeableLockFreeQueue() =default | |
| ~ResizeableLockFreeQueue() =default | |
| ResizeableLockFreeQueue(const ResizeableLockFreeQueue & ) | |
| ResizeableLockFreeQueue(ResizeableLockFreeQueue && ) | |
| ResizeableLockFreeQueue & | operator=(const ResizeableLockFreeQueue & ) |
| ResizeableLockFreeQueue & | operator=(ResizeableLockFreeQueue && ) |
| ResizeableLockFreeQueue(const uint64_t initialCapacity) | |
| uint64_t | capacity() const returns the current capacity of the queue |
| iox::cxx::optional< ElementType > | push(const ElementType & value) 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) inserts value in FIFO order, always succeeds by removing the oldest value when the queue is detected to be full (overflow) |
| template <typename Function ,typename =typename std::enable_if bool |
setCapacity(const uint64_t newCapacity, Function && removeHandler) Set the capacity to some value. |
| bool | setCapacity(const uint64_t newCapacity) Set the capacity to a new capacity between 0 and MaxCapacity, if the capacity is reduced it may be necessary to remove the least recent elements which are then discarded. |
| constexpr uint64_t | maxCapacity() returns the maximum capacity of the queue |
Public Attributes🔗
| Name | |
|---|---|
| constexpr uint64_t | MAX_CAPACITY |
Additional inherited members🔗
Protected Types inherited from iox::concurrent::LockFreeQueue< ElementType, MaxCapacity >
| Name | |
|---|---|
| using IndexQueue< Capacity > | Queue |
Public Functions inherited from iox::concurrent::LockFreeQueue< ElementType, MaxCapacity >
| Name | |
|---|---|
| LockFreeQueue() creates and initalizes an empty LockFreeQueue |
|
| ~LockFreeQueue() =default | |
| LockFreeQueue(const LockFreeQueue & ) | |
| LockFreeQueue(LockFreeQueue && ) | |
| bool | tryPush(ElementType && value) tries to insert value in FIFO order, moves the value internally |
| bool | tryPush(const ElementType & value) tries to insert value in FIFO order, copies the value internally |
| iox::cxx::optional< ElementType > | pop() tries to remove value in FIFO order |
| bool | empty() const check whether the queue is empty |
| uint64_t | size() const get the number of stored elements in the queue |
Protected Functions inherited from iox::concurrent::LockFreeQueue< ElementType, MaxCapacity >
| Name | |
|---|---|
| template <typename T > void |
writeBufferAt(const BufferIndex & , T && ) |
| cxx::optional< ElementType > | readBufferAt(const BufferIndex & ) |
Protected Attributes inherited from iox::concurrent::LockFreeQueue< ElementType, MaxCapacity >
| Name | |
|---|---|
| Queue | m_freeIndices |
| Queue | m_usedIndices |
| Buffer< ElementType, Capacity, BufferIndex > | m_buffer |
| std::atomic< uint64_t > | m_size |
Detailed Description🔗
template <typename ElementType ,
uint64_t MaxCapacity>
class iox::concurrent::ResizeableLockFreeQueue;
implements a lock free queue (i.e. container with FIFO order) of elements of type T with a maximum capacity MaxCapacity. The capacity can be defined to be anything between 0 and MaxCapacity at construction time or later at runtime using setCapacity. This is even possible while concurrent push and pop operations are executed, i.e. the queue does not have to be empty. Only one thread will succeed setting its desired capacity if there are more threads trying to change the capacity at the same time (it is unpredictable which thread).
Public Types Documentation🔗
using element_t🔗
using iox::concurrent::ResizeableLockFreeQueue< ElementType, MaxCapacity >::element_t = ElementType;
Public Functions Documentation🔗
function ResizeableLockFreeQueue🔗
ResizeableLockFreeQueue() =default
function ~ResizeableLockFreeQueue🔗
~ResizeableLockFreeQueue() =default
function ResizeableLockFreeQueue🔗
ResizeableLockFreeQueue(
const ResizeableLockFreeQueue &
)
function ResizeableLockFreeQueue🔗
ResizeableLockFreeQueue(
ResizeableLockFreeQueue &&
)
function operator=🔗
ResizeableLockFreeQueue & operator=(
const ResizeableLockFreeQueue &
)
function operator=🔗
ResizeableLockFreeQueue & operator=(
ResizeableLockFreeQueue &&
)
function ResizeableLockFreeQueue🔗
ResizeableLockFreeQueue(
const uint64_t initialCapacity
)
function capacity🔗
uint64_t capacity() const
returns the current capacity of the queue
Return: the current capacity
Note: threadsafe, lockfree
function push🔗
iox::cxx::optional< ElementType > push(
const ElementType & value
)
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
Return: removed value if an overflow occured, empty optional otherwise
Note: threadsafe, lockfree
function push🔗
iox::cxx::optional< ElementType > push(
ElementType && value
)
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
Return: removed value if an overflow occured, empty optional otherwise
Note: threadsafe, lockfree
function setCapacity🔗
template <typename Function ,
typename =typename std::enable_if<cxx::is_invocable<Function, ElementType>::value>::type>
bool setCapacity(
const uint64_t newCapacity,
Function && removeHandler
)
Set the capacity to some value.
Parameters:
- newCapacity capacity to be set
- removeHandler is a function taking an element which specifies what to do with removed elements should the need for removal arise.
Return: true if the capacity was successfully set, false otherwise
Note: setCapacity is lockfree, but if an application crashes during setCapacity it currently may prevent other applications from setting the capacity (they will not block though). This is not a problem if for example there is only one application calling setCapacity or setCapacity is only called from vital applications (which if they crash will lead to system shutdown) and there is only one (non-vital, i.e. allowed to crash) application reading the data via pop. The reader application may also call setCapacity, since if it crashes there is no one reading the data and the capacity can be considered meaningless.
function setCapacity🔗
bool setCapacity(
const uint64_t newCapacity
)
Set the capacity to a new capacity between 0 and MaxCapacity, if the capacity is reduced it may be necessary to remove the least recent elements which are then discarded.
Parameters:
- newCapacity new capacity to be set, if it is larger than MaxCapacity the call fails
Return: true setting if the new capacity was successful, false otherwise (newCapacity > MaxCapacity)
Note: threadsafe, lockfree but multiple concurrent calls may have no effect
function maxCapacity🔗
static constexpr uint64_t maxCapacity()
returns the maximum capacity of the queue
Return: the maximum capacity
Public Attributes Documentation🔗
variable MAX_CAPACITY🔗
static constexpr uint64_t MAX_CAPACITY = MaxCapacity;
Updated on 2 April 2022 at 16:37:47 CEST