1
2 /*
3 * Copyright (C) NGINX, Inc.
4 */
5
6 #ifndef _NXT_PORT_QUEUE_H_INCLUDED_
7 #define _NXT_PORT_QUEUE_H_INCLUDED_
8
9
10 #include <nxt_nncq.h>
11
12
13 /* Using Numeric Naive Circular Queue as a backend. */
14
15 #define NXT_PORT_QUEUE_SIZE NXT_NNCQ_SIZE
16 #define NXT_PORT_QUEUE_MSG_SIZE 31
17
18
19 typedef struct {
20 uint8_t size;
21 uint8_t data[NXT_PORT_QUEUE_MSG_SIZE];
22 } nxt_port_queue_item_t;
23
24
25 typedef struct {
26 nxt_nncq_atomic_t nitems;
27 nxt_nncq_t free_items;
28 nxt_nncq_t queue;
29 nxt_port_queue_item_t items[NXT_PORT_QUEUE_SIZE];
30 } nxt_port_queue_t;
31
32
33 nxt_inline void
nxt_port_queue_init(nxt_port_queue_t volatile * q)34 nxt_port_queue_init(nxt_port_queue_t volatile *q)
35 {
36 nxt_nncq_atomic_t i;
37
38 nxt_nncq_init(&q->free_items);
39 nxt_nncq_init(&q->queue);
40
41 for (i = 0; i < NXT_PORT_QUEUE_SIZE; i++) {
42 nxt_nncq_enqueue(&q->free_items, i);
43 }
44
45 q->nitems = 0;
46 }
47
48
49 nxt_inline nxt_int_t
nxt_port_queue_send(nxt_port_queue_t volatile * q,const void * p,uint8_t size,int * notify)50 nxt_port_queue_send(nxt_port_queue_t volatile *q, const void *p, uint8_t size,
51 int *notify)
52 {
53 nxt_nncq_atomic_t i;
54 nxt_port_queue_item_t *qi;
55
56 i = nxt_nncq_dequeue(&q->free_items);
57 if (i == nxt_nncq_empty(&q->free_items)) {
58 *notify = 0;
59 return NXT_AGAIN;
60 }
61
62 qi = (nxt_port_queue_item_t *) &q->items[i];
63
64 qi->size = size;
65 nxt_memcpy(qi->data, p, size);
66
67 nxt_nncq_enqueue(&q->queue, i);
68
69 i = nxt_atomic_fetch_add(&q->nitems, 1);
70
71 *notify = (i == 0);
72
73 return NXT_OK;
74 }
75
76
77 nxt_inline ssize_t
nxt_port_queue_recv(nxt_port_queue_t volatile * q,void * p)78 nxt_port_queue_recv(nxt_port_queue_t volatile *q, void *p)
79 {
80 ssize_t res;
81 nxt_nncq_atomic_t i;
82 nxt_port_queue_item_t *qi;
83
84 i = nxt_nncq_dequeue(&q->queue);
85 if (i == nxt_nncq_empty(&q->queue)) {
86 return -1;
87 }
88
89 qi = (nxt_port_queue_item_t *) &q->items[i];
90
91 res = qi->size;
92 nxt_memcpy(p, qi->data, qi->size);
93
94 nxt_nncq_enqueue(&q->free_items, i);
95
96 nxt_atomic_fetch_add(&q->nitems, -1);
97
98 return res;
99 }
100
101
102 #endif /* _NXT_PORT_QUEUE_H_INCLUDED_ */
103