1/* $NetBSD: pthread_queue.h,v 1.7 2022/04/19 20:32:17 rillig Exp $ */
2
3/*-
4 * Copyright (c) 2001 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Nathan J. Williams.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32#ifndef _LIB_PTHREAD_QUEUE_H
33#define _LIB_PTHREAD_QUEUE_H
34
35/*
36 * Definition of a queue interface for the pthread library.
37 * Style modeled on the sys/queue.h macros; implementation taken from
38 * the tail queue, with the added property of static initializability
39 * (and a corresponding extra cost in the _INSERT_TAIL() function.
40*/
41
42/*
43 * Queue definitions.
44 */
45
46#define PTQ_HEAD(name, type) \
47struct name { \
48 struct type *ptqh_first;/* first element */ \
49 struct type **ptqh_last;/* addr of last next element */ \
50}
51
52#define PTQ_HEAD_INITIALIZER { NULL, NULL }
53
54#define PTQ_ENTRY(type) \
55struct { \
56 struct type *ptqe_next; /* next element */ \
57 struct type **ptqe_prev;/* address of previous next element */ \
58}
59
60/*
61 * Queue functions.
62 */
63
64#define PTQ_INIT(head) do { \
65 (head)->ptqh_first = NULL; \
66 (head)->ptqh_last = &(head)->ptqh_first; \
67} while (0)
68
69#define PTQ_INSERT_HEAD(head, elm, field) do { \
70 if (((elm)->field.ptqe_next = (head)->ptqh_first) != NULL) \
71 (head)->ptqh_first->field.ptqe_prev = \
72 &(elm)->field.ptqe_next; \
73 else \
74 (head)->ptqh_last = &(elm)->field.ptqe_next; \
75 (head)->ptqh_first = (elm); \
76 (elm)->field.ptqe_prev = &(head)->ptqh_first; \
77} while (0)
78
79#define PTQ_INSERT_TAIL(head, elm, field) do { \
80 (elm)->field.ptqe_next = NULL; \
81 if ((head)->ptqh_last == NULL) \
82 (head)->ptqh_last = &(head)->ptqh_first; \
83 (elm)->field.ptqe_prev = (head)->ptqh_last; \
84 *(head)->ptqh_last = (elm); \
85 (head)->ptqh_last = &(elm)->field.ptqe_next; \
86} while (0)
87
88#define PTQ_INSERT_AFTER(head, listelm, elm, field) do { \
89 if (((elm)->field.ptqe_next = (listelm)->field.ptqe_next) != NULL)\
90 (elm)->field.ptqe_next->field.ptqe_prev = \
91 &(elm)->field.ptqe_next; \
92 else \
93 (head)->ptqh_last = &(elm)->field.ptqe_next; \
94 (listelm)->field.ptqe_next = (elm); \
95 (elm)->field.ptqe_prev = &(listelm)->field.ptqe_next; \
96} while (0)
97
98#define PTQ_INSERT_BEFORE(listelm, elm, field) do { \
99 (elm)->field.ptqe_prev = (listelm)->field.ptqe_prev; \
100 (elm)->field.ptqe_next = (listelm); \
101 *(listelm)->field.ptqe_prev = (elm); \
102 (listelm)->field.ptqe_prev = &(elm)->field.ptqe_next; \
103} while (0)
104
105#define PTQ_REMOVE(head, elm, field) do { \
106 if (((elm)->field.ptqe_next) != NULL) \
107 (elm)->field.ptqe_next->field.ptqe_prev = \
108 (elm)->field.ptqe_prev; \
109 else \
110 (head)->ptqh_last = (elm)->field.ptqe_prev; \
111 *(elm)->field.ptqe_prev = (elm)->field.ptqe_next; \
112} while (0)
113
114/*
115 * Queue access methods.
116 */
117
118#define PTQ_EMPTY(head) ((head)->ptqh_first == NULL)
119#define PTQ_FIRST(head) ((head)->ptqh_first)
120#define PTQ_NEXT(elm, field) ((elm)->field.ptqe_next)
121
122#define PTQ_LAST(head, headname) \
123 (*(((struct headname *)(void *)((head)->ptqh_last))->ptqh_last))
124#define PTQ_PREV(elm, headname, field) \
125 (*(((struct headname *)(void *)((elm)->field.ptqe_prev))->ptqh_last))
126
127#define PTQ_FOREACH(var, head, field) \
128 for ((var) = ((head)->ptqh_first); \
129 (var); \
130 (var) = ((var)->field.ptqe_next))
131
132#define PTQ_FOREACH_REVERSE(var, head, headname, field) \
133 for ((var) = (*(((struct headname *)(void *)((head)->ptqh_last))->ptqh_last)); \
134 (var); \
135 (var) = (*(((struct headname *)(void *)((var)->field.ptqe_prev))->ptqh_last)))
136
137#endif /* _LIB_PTHREAD_QUEUE_H */