1 /*
2  * Copyright (c) 2016-2017 Nordic Semiconductor ASA
3  * Copyright (c) 2016 Vinayak Kariappa Chettimada
4  *
5  * SPDX-License-Identifier: Apache-2.0
6  */
7 
8 /**
9  * @brief   Element of a memory-queue
10  * @details Elements form a linked list, and as payload carries a pointer
11  */
12 struct _memq_link {
13 	struct _memq_link *next; /* permit chaining */
14 	void              *mem;  /* payload */
15 };
16 
17 typedef struct _memq_link memq_link_t;
18 
19 #define MEMQ_DECLARE(name) \
20 	struct { \
21 		memq_link_t *head; \
22 		memq_link_t *tail; \
23 	} memq_##name
24 
25 memq_link_t *memq_init(memq_link_t *link, memq_link_t **head,
26 		       memq_link_t **tail);
27 
28 #define MEMQ_INIT(name, link) \
29 	memq_init(link, &memq_##name.head, &memq_##name.tail)
30 
31 memq_link_t *memq_deinit(memq_link_t **head, memq_link_t **tail);
32 memq_link_t *memq_enqueue(memq_link_t *link, void *mem, memq_link_t **tail);
33 memq_link_t *memq_peek(memq_link_t *head, memq_link_t *tail, void **mem);
34 memq_link_t *memq_peek_n(memq_link_t *head, memq_link_t *tail, uint8_t n,
35 			 void **mem);
36 memq_link_t *memq_dequeue(memq_link_t *tail, memq_link_t **head, void **mem);
37