Single Producer Single Consumer Lock Free Queue

A Single Producer Single Consumer Lock Free Queue (SPSC) is a lock free atomic ring buffer based queue.

API Reference

group spsc_lockfree

Single Producer Single Consumer (SPSC) Lockfree Queue API.

Defines

SPSC_INITIALIZER(sz, buf)

Statically initialize an spsc.

Parameters:

  • sz – Size of the spsc, must be power of 2 (ex: 2, 4, 8)

  • buf – Buffer pointer

SPSC_DECLARE(name, type)

Declare an anonymous struct type for an spsc.

Parameters:

  • name – Name of the spsc symbol to be provided

  • type – Type stored in the spsc

SPSC_DEFINE(name, type, sz)

Define an spsc with a fixed size.

Parameters:

  • name – Name of the spsc symbol to be provided

  • type – Type stored in the spsc

  • sz – Size of the spsc, must be power of 2 (ex: 2, 4, 8)

spsc_size(spsc)

Size of the SPSC queue.

Parameters:

  • spsc – SPSC reference

spsc_reset(spsc)

Initialize/reset a spsc such that its empty.

Note that this is not safe to do while being used in a producer/consumer situation with multiple calling contexts (isrs/threads).

Parameters:

  • spsc – SPSC to initialize/reset

spsc_acquire(spsc)

Acquire an element to produce from the SPSC.

Parameters:

  • spsc – SPSC to acquire an element from for producing

Returns:

A pointer to the acquired element or null if the spsc is full

spsc_produce(spsc)

Produce one previously acquired element to the SPSC.

This makes one element available to the consumer immediately

Parameters:

  • spsc – SPSC to produce the previously acquired element or do nothing

spsc_produce_all(spsc)

Produce all previously acquired elements to the SPSC.

This makes all previous acquired elements available to the consumer immediately

Parameters:

  • spsc – SPSC to produce all previously acquired elements or do nothing

spsc_drop_all(spsc)

Drop all previously acquired elements.

This makes all previous acquired elements available to be acquired again

Parameters:

  • spsc – SPSC to drop all previously acquired elements or do nothing

spsc_consume(spsc)

Consume an element from the spsc.

Parameters:

  • spsc – Spsc to consume from

Returns:

Pointer to element or null if no consumable elements left

spsc_release(spsc)

Release a consumed element.

Parameters:

  • spsc – SPSC to release consumed element or do nothing

spsc_release_all(spsc)

Release all consumed elements.

Parameters:

  • spsc – SPSC to release consumed elements or do nothing

spsc_acquirable(spsc)

Count of acquirable in spsc.

Parameters:

  • spsc – SPSC to get item count for

spsc_consumable(spsc)

Count of consumables in spsc.

Parameters:

  • spsc – SPSC to get item count for

spsc_peek(spsc)

Peek at the first available item in queue.

Parameters:

  • spsc – Spsc to peek into

Returns:

Pointer to element or null if no consumable elements left

spsc_next(spsc, item)

Peek at the next item in the queue from a given one.

Parameters:

  • spsc – SPSC to peek at

  • item – Pointer to an item in the queue

Returns:

Pointer to element or null if none left

spsc_prev(spsc, item)

Get the previous item in the queue from a given one.

Parameters:

  • spsc – SPSC to peek at

  • item – Pointer to an item in the queue

Returns:

Pointer to element or null if none left

struct spsc

Common SPSC attributes.

Warning

Not to be manipulated without the macros!