386BSD 0.1 development
[unix-history] / usr / src / sys.386bsd / vm / queue.h
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1/*
2 * Copyright (c) 1991 Regents of the University of California.
3 * All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * The Mach Operating System project at Carnegie-Mellon University.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 * @(#)queue.h 7.3 (Berkeley) 4/21/91
37 *
38 *
39 * Copyright (c) 1987, 1990 Carnegie-Mellon University.
40 * All rights reserved.
41 *
42 * Author: Avadis Tevanian, Jr.
43 *
44 * Permission to use, copy, modify and distribute this software and
45 * its documentation is hereby granted, provided that both the copyright
46 * notice and this permission notice appear in all copies of the
47 * software, derivative works or modified versions, and any portions
48 * thereof, and that both notices appear in supporting documentation.
49 *
50 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
51 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
52 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
53 *
54 * Carnegie Mellon requests users of this software to return to
55 *
56 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
57 * School of Computer Science
58 * Carnegie Mellon University
59 * Pittsburgh PA 15213-3890
60 *
61 * any improvements or extensions that they make and grant Carnegie the
62 * rights to redistribute these changes.
63 */
64
65/*
66 * Type definitions for generic queues.
67 */
68
69#ifndef _QUEUE_H_
70#define _QUEUE_H_
71
72struct queue_entry {
73 struct queue_entry *next; /* next element */
74 struct queue_entry *prev; /* previous element */
75};
76
77typedef struct queue_entry *queue_t;
78typedef struct queue_entry queue_head_t;
79typedef struct queue_entry queue_chain_t;
80typedef struct queue_entry *queue_entry_t;
81
82#define round_queue(size) (((size)+7) & (~7))
83
84#define enqueue(queue,elt) enqueue_tail(queue, elt)
85#define dequeue(queue) dequeue_head(queue)
86
87#define enqueue_head(queue,elt) insque(elt,queue)
88#define enqueue_tail(queue,elt) insque(elt,(queue)->prev)
89#define remqueue(queue,elt) remque(elt)
90
91#define queue_init(q) ((q)->next = (q)->prev = q)
92#define queue_first(q) ((q)->next)
93#define queue_next(qc) ((qc)->next)
94#define queue_end(q, qe) ((q) == (qe))
95#define queue_empty(q) queue_end((q), queue_first(q))
96
97#define queue_enter(head, elt, type, field) { \
98 if (queue_empty((head))) { \
99 (head)->next = (queue_entry_t) elt; \
100 (head)->prev = (queue_entry_t) elt; \
101 (elt)->field.next = head; \
102 (elt)->field.prev = head; \
103 } else { \
104 register queue_entry_t prev = (head)->prev; \
105 (elt)->field.prev = prev; \
106 (elt)->field.next = head; \
107 (head)->prev = (queue_entry_t)(elt); \
108 ((type)prev)->field.next = (queue_entry_t)(elt);\
109 } \
110}
111
112#define queue_field(head, thing, type, field) \
113 (((head) == (thing)) ? (head) : &((type)(thing))->field)
114
115#define queue_remove(head, elt, type, field) { \
116 register queue_entry_t next = (elt)->field.next; \
117 register queue_entry_t prev = (elt)->field.prev; \
118 queue_field((head), next, type, field)->prev = prev; \
119 queue_field((head), prev, type, field)->next = next; \
120}
121
122#define queue_assign(to, from, type, field) { \
123 ((type)((from)->prev))->field.next = (to); \
124 ((type)((from)->next))->field.prev = (to); \
125 *to = *from; \
126}
127
128#define queue_remove_first(h, e, t, f) { \
129 e = (t) queue_first((h)); \
130 queue_remove((h), (e), t, f); \
131}
132
133#endif /* !_QUEUE_H_ */