LockFreeQueue< T > Class Template Reference

A lock-free FIFO queue for single-producer, single-consumer scenarios. More...

#include <gin_lockfreequeue.h>

Public Member Functions
	LockFreeQueue (int capacity=128)
	Creates a lock-free queue with the specified capacity.
void	setSize (int capacity)
	Resizes the queue to a new capacity.
int	getFreeSpace () const noexcept
	Returns the number of free slots available for writing.
int	getNumReady () const noexcept
	Returns the number of items ready to be read.
void	reset () noexcept
	Resets the queue to an empty state.
bool	write (T item)
	Writes an item to the queue.
std::optional< T >	peek ()
	Peeks at the next item in the queue without removing it.
std::optional< T >	read ()
	Reads and removes the next item from the queue.
bool	pop (int num)
	Removes (pops) multiple items from the queue without returning them.

Detailed Description

template<typename T>
class LockFreeQueue< T >

A lock-free FIFO queue for single-producer, single-consumer scenarios.

This template class provides a thread-safe queue that can be used to pass objects between threads without using locks. It's built on top of JUCE's AbstractFifo and is suitable for real-time audio processing where blocking is not acceptable.

The queue uses a circular buffer internally and supports write, read, peek, and pop operations. All operations are lock-free and safe for use between one producer thread and one consumer thread.

Example usage:

LockFreeQueue<int> queue (100);
 
// Producer thread
queue.write (42);
queue.write (123);
 
// Consumer thread
auto value = queue.read();
if (value.has_value())
    process (*value);

Template Parameters

T	The type of objects to store in the queue. Must be copyable.

Constructor & Destructor Documentation

LockFreeQueue()

template<typename T >

LockFreeQueue< T >::LockFreeQueue

(

int

capacity = 128

)

Creates a lock-free queue with the specified capacity.

Parameters

capacity

The maximum number of items the queue can hold (default: 128)

Member Function Documentation

setSize()

template<typename T >

void LockFreeQueue< T >::setSize

(

int

capacity

)

Resizes the queue to a new capacity.

Note: This is not thread-safe and should only be called when no other threads are accessing the queue.

Parameters

capacity

The new maximum number of items the queue can hold

getFreeSpace()

template<typename T >

int LockFreeQueue< T >::getFreeSpace ( ) const

noexcept

Returns the number of free slots available for writing.

Returns

The number of items that can be written before the queue is full

getNumReady()

template<typename T >

int LockFreeQueue< T >::getNumReady ( ) const

noexcept

Returns the number of items ready to be read.

Returns

The number of items currently in the queue

reset()

template<typename T >

void LockFreeQueue< T >::reset ( )

noexcept

Resets the queue to an empty state.

Note: This is not thread-safe and should only be called when no other threads are accessing the queue.

write()

template<typename T >

bool LockFreeQueue< T >::write

(

T

item

)

Writes an item to the queue.

This should only be called from the producer thread.

Parameters

item	The item to write to the queue

Returns

true if the write succeeded, false if the queue was full

peek()

template<typename T >

std::optional< T > LockFreeQueue< T >::peek

(

)

Peeks at the next item in the queue without removing it.

This should only be called from the consumer thread.

Returns

An optional containing the next item, or std::nullopt if the queue is empty

read()

template<typename T >

std::optional< T > LockFreeQueue< T >::read

(

)

Reads and removes the next item from the queue.

This should only be called from the consumer thread.

Returns

An optional containing the next item, or std::nullopt if the queue is empty

pop()

template<typename T >

bool LockFreeQueue< T >::pop

(

int

num

)

Removes (pops) multiple items from the queue without returning them.

This is useful for discarding items you've already processed via peek(). This should only be called from the consumer thread.

Parameters

num	The number of items to remove from the queue

Returns

true if the pop succeeded, false if there weren't enough items

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

• gin_lockfreequeue.h