openmv/common/queue.h
iabdalkader 50c9be73c8 common: Add SPSC lock-free queue.
Signed-off-by: iabdalkader <i.abdalkader@gmail.com>
2025-07-23 18:24:52 +02:00

62 lines
2.1 KiB
C

/*
* SPDX-License-Identifier: MIT
*
* Copyright (C) 2013-2024 OpenMV, LLC.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*
* Single-producer, single-consumer, lock-free bounded Queue.
*/
#ifndef __QUEUE_H__
#define __QUEUE_H__
#include <stddef.h>
#include <stdbool.h>
#if __STDC_VERSION__ < 201112L
typedef size_t queue_index_t;
#warning "Atomics not supported"
#else
#include <stdatomic.h>
#define HAVE_STDATOMIC_H
typedef atomic_size_t queue_index_t;
#endif
typedef struct {
size_t capacity;
queue_index_t head;
queue_index_t tail; // TODO pad with cache line if needed.
void *items[];
} queue_t;
// One extra slot is used to distinguish full from empty.
#define queue_calc_size(capacity) \
(sizeof(queue_t) + ((capacity) + 1) * sizeof(void *))
void queue_init(queue_t **q, size_t capacity, void *buffer);
void queue_flush(queue_t *q);
queue_t *queue_alloc(size_t capacity);
void queue_destroy(queue_t *q);
bool queue_is_empty(const queue_t *q);
bool queue_push(queue_t *q, void *item);
void *queue_pop(queue_t *q, bool peek);
size_t queue_size(const queue_t *q);
void *queue_swap(queue_t *q0, queue_t *q1);
#endif // __QUEUE_H__