ring_buffer.c

// SPDX-License-Identifier: BSD-3-Clause

#include <stdlib.h>
#include <string.h>
#include <pthread.h>
#include "ring_buffer.h"

int ring_buffer_init(so_ring_buffer_t *ring, size_t cap)
{
	ring->data = malloc(cap);
	ring->read_pos = 0;
	ring->write_pos = 0;
	ring->len = 0;
	ring->cap = cap;
	ring->stop = 0;
	pthread_mutex_init(&ring->mutex, NULL);
	pthread_cond_init(&ring->cond_not_empty, NULL);
	pthread_cond_init(&ring->cond_not_full, NULL);
	return 0;
}

ssize_t ring_buffer_enqueue(so_ring_buffer_t *ring, void *data, size_t size)
{
	pthread_mutex_lock(&ring->mutex);
	while (!ring->stop && ring->cap < size + ring->len)
		pthread_cond_wait(&ring->cond_not_full, &ring->mutex);
	if (ring->stop) {
		pthread_mutex_unlock(&ring->mutex);
		return -1;
	}
	memcpy(ring->data + ring->write_pos, data, size);
	ring->write_pos = (ring->write_pos + size) % ring->cap;
	ring->len += size;
	pthread_cond_signal(&ring->cond_not_empty);
	pthread_mutex_unlock(&ring->mutex);
	return size;
}

ssize_t ring_buffer_dequeue(so_ring_buffer_t *ring, void *data, size_t size)
{
	pthread_mutex_lock(&ring->mutex);
	while (!ring->stop && ring->len < size)
		pthread_cond_wait(&ring->cond_not_empty, &ring->mutex);
	if (ring->stop && ring->len < size) {
		pthread_mutex_unlock(&ring->mutex);
		return -1;
	}
	memcpy(data, ring->data + ring->read_pos, size);
	ring->read_pos = (ring->read_pos + size) % ring->cap;
	ring->len -= size;
	pthread_cond_signal(&ring->cond_not_full);
	pthread_mutex_unlock(&ring->mutex);
	return size;
}

void ring_buffer_stop(so_ring_buffer_t *ring)
{
	pthread_mutex_lock(&ring->mutex);
	ring->stop = 1;
	pthread_cond_broadcast(&ring->cond_not_empty);
	pthread_cond_broadcast(&ring->cond_not_full);
	pthread_mutex_unlock(&ring->mutex);
}

void ring_buffer_destroy(so_ring_buffer_t *ring)
{
	free(ring->data);
	pthread_mutex_destroy(&ring->mutex);
	pthread_cond_destroy(&ring->cond_not_empty);
	pthread_cond_destroy(&ring->cond_not_full);
}