ThreadSafeCircularQueue< ValueType, capacity > Class Template Reference

An circular queue meant for sharing data across threads. More...

#include <threadsafecircularqueue.h>

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Classes
struct	StorageType

Public Types
using	value_type = ValueType

Public Member Functions
template<typename VT >
void	push_back (VT &&value)
	Add or move an item into the queue. More...
template<typename VT >
bool	try_push_back (VT &&value, const std::chrono::milliseconds &wait_duration=std::chrono::milliseconds::zero())
	Add or move an item into the queue. More...
ValueType	pop_front (int *overflows=nullptr, time_t *sent_time=nullptr)
	Retrieve an item from the queue. More...
bool	try_pop_front (ValueType *value, int *overflows=nullptr, time_t *sent_time=nullptr, std::chrono::milliseconds wait_duration=std::chrono::milliseconds::zero())
	Retrieve an item from the queue. More...

Private Types
using	index_type = uint32_t

Private Member Functions
index_type	next (index_type index)
	Increment an index, wrapping around buffer size. More...
void	write_common ()
	Perform actions common to the various forms of push_back. More...

Private Attributes
StorageType	data [capacity]
std::atomic< index_type >	read_index
std::mutex	read_mutex
std::condition_variable	read_bell
std::atomic< index_type >	write_index
std::mutex	write_mutex
std::condition_variable	write_bell

Detailed Description

template<typename ValueType, uint32_t capacity>
class ThreadSafeCircularQueue< ValueType, capacity >

An circular queue meant for sharing data across threads.

Template Parameters

ValueType	Type of objects being passed around.
capacity	The maximum capacity of the queue.

Member Typedef Documentation

index_type

template<typename ValueType , uint32_t capacity>

using ThreadSafeCircularQueue< ValueType, capacity >::index_type = uint32_t

private

value_type

template<typename ValueType , uint32_t capacity>

using ThreadSafeCircularQueue< ValueType, capacity >::value_type = ValueType

Member Function Documentation

next()

template<typename ValueType , uint32_t capacity>

index_type ThreadSafeCircularQueue< ValueType, capacity >::next ( index_type  index )

inlineprivate

Increment an index, wrapping around buffer size.

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pop_front()

template<typename ValueType , uint32_t capacity>

ValueType ThreadSafeCircularQueue< ValueType, capacity >::pop_front ( int *  overflows = nullptr, time_t *  sent_time = nullptr  )

inline

Retrieve an item from the queue.

If the queue is empty, block until an item becomes available.

Parameters

overflows	If non-null, set to the number of items dropped due to overflow.
sent_time	If non-null, the time at which the item was queued.

Returns

The next value from the queue.

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push_back()

template<typename ValueType , uint32_t capacity>

template<typename VT >

void ThreadSafeCircularQueue< ValueType, capacity >::push_back ( VT &&  value )

inline

Add or move an item into the queue.

If the queue is full, wait until there's space.

Parameters

value

The value to add.

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try_pop_front()

template<typename ValueType , uint32_t capacity>

bool ThreadSafeCircularQueue< ValueType, capacity >::try_pop_front ( ValueType *  value, int *  overflows = nullptr, time_t *  sent_time = nullptr, std::chrono::milliseconds  wait_duration = std::chrono::milliseconds::zero()  )

inline

Retrieve an item from the queue.

If the queue is empty, don't block.

Parameters

value	On return, set to the value retrieved from the queue.
overflows	If non-null, set to the number of items dropped due to overflow.
sent_time	If non-null, the time at which the item was queued.
wait_duration	A duration to wait for for an item; defaults to no wait.

Returns

True if a value was retrieved, false if the queue was empty.

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try_push_back()

template<typename ValueType , uint32_t capacity>

template<typename VT >

bool ThreadSafeCircularQueue< ValueType, capacity >::try_push_back ( VT &&  value, const std::chrono::milliseconds &  wait_duration = std::chrono::milliseconds::zero()  )

inline

Add or move an item into the queue.

If the queue is full, mark that an overflow occured, and do not block.

Parameters

value	The value to add.
wait_duration	Optional: If specified, a duration to wait before giving up. Default is to not wait. Observation, however, shows that small waits can go a long way to reduce overflows, providing a chance for readers to catch up when the queue is full.

Returns

True on success, false on overflow.

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write_common()

template<typename ValueType , uint32_t capacity>

void ThreadSafeCircularQueue< ValueType, capacity >::write_common ( )

inlineprivate

Perform actions common to the various forms of push_back.

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Member Data Documentation

data

template<typename ValueType , uint32_t capacity>

StorageType ThreadSafeCircularQueue< ValueType, capacity >::data[capacity]

private

read_bell

template<typename ValueType , uint32_t capacity>

std::condition_variable ThreadSafeCircularQueue< ValueType, capacity >::read_bell

private

read_index

template<typename ValueType , uint32_t capacity>

std::atomic<index_type> ThreadSafeCircularQueue< ValueType, capacity >::read_index

private

read_mutex

template<typename ValueType , uint32_t capacity>

std::mutex ThreadSafeCircularQueue< ValueType, capacity >::read_mutex

private

write_bell

template<typename ValueType , uint32_t capacity>

std::condition_variable ThreadSafeCircularQueue< ValueType, capacity >::write_bell

private

write_index

template<typename ValueType , uint32_t capacity>

std::atomic<index_type> ThreadSafeCircularQueue< ValueType, capacity >::write_index

private

write_mutex

template<typename ValueType , uint32_t capacity>

std::mutex ThreadSafeCircularQueue< ValueType, capacity >::write_mutex

private

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

• common/threadsafecircularqueue.h