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/*
* Copyright (C) NGINX, Inc.
*/
#ifndef _NXT_PORT_QUEUE_H_INCLUDED_
#define _NXT_PORT_QUEUE_H_INCLUDED_
#include <nxt_nncq.h>
/* Using Numeric Naive Circular Queue as a backend. */
#define NXT_PORT_QUEUE_SIZE NXT_NNCQ_SIZE
#define NXT_PORT_QUEUE_MSG_SIZE 31
typedef struct {
uint8_t size;
uint8_t data[NXT_PORT_QUEUE_MSG_SIZE];
} nxt_port_queue_item_t;
typedef struct {
nxt_nncq_atomic_t nitems;
nxt_nncq_t free_items;
nxt_nncq_t queue;
nxt_port_queue_item_t items[NXT_PORT_QUEUE_SIZE];
} nxt_port_queue_t;
nxt_inline void
nxt_port_queue_init(nxt_port_queue_t volatile *q)
{
nxt_nncq_atomic_t i;
nxt_nncq_init(&q->free_items);
nxt_nncq_init(&q->queue);
for (i = 0; i < NXT_PORT_QUEUE_SIZE; i++) {
nxt_nncq_enqueue(&q->free_items, i);
}
q->nitems = 0;
}
nxt_inline nxt_int_t
nxt_port_queue_send(nxt_port_queue_t volatile *q, const void *p, uint8_t size,
int *notify)
{
nxt_nncq_atomic_t i;
nxt_port_queue_item_t *qi;
i = nxt_nncq_dequeue(&q->free_items);
if (i == nxt_nncq_empty(&q->free_items)) {
*notify = 0;
return NXT_AGAIN;
}
qi = (nxt_port_queue_item_t *) &q->items[i];
qi->size = size;
nxt_memcpy(qi->data, p, size);
nxt_nncq_enqueue(&q->queue, i);
i = nxt_atomic_fetch_add(&q->nitems, 1);
*notify = (i == 0);
return NXT_OK;
}
nxt_inline ssize_t
nxt_port_queue_recv(nxt_port_queue_t volatile *q, void *p)
{
ssize_t res;
nxt_nncq_atomic_t i;
nxt_port_queue_item_t *qi;
i = nxt_nncq_dequeue(&q->queue);
if (i == nxt_nncq_empty(&q->queue)) {
return -1;
}
qi = (nxt_port_queue_item_t *) &q->items[i];
res = qi->size;
nxt_memcpy(p, qi->data, qi->size);
nxt_nncq_enqueue(&q->free_items, i);
nxt_atomic_fetch_add(&q->nitems, -1);
return res;
}
#endif /* _NXT_PORT_QUEUE_H_INCLUDED_ */
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