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[unix-history] / sys / 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
78ed81a3 37 * $Id$
38 */
39
40/*
15637ed4
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41 * Copyright (c) 1987, 1990 Carnegie-Mellon University.
42 * All rights reserved.
43 *
44 * Author: Avadis Tevanian, Jr.
45 *
46 * Permission to use, copy, modify and distribute this software and
47 * its documentation is hereby granted, provided that both the copyright
48 * notice and this permission notice appear in all copies of the
49 * software, derivative works or modified versions, and any portions
50 * thereof, and that both notices appear in supporting documentation.
51 *
52 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
53 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
54 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
55 *
56 * Carnegie Mellon requests users of this software to return to
57 *
58 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
59 * School of Computer Science
60 * Carnegie Mellon University
61 * Pittsburgh PA 15213-3890
62 *
63 * any improvements or extensions that they make and grant Carnegie the
64 * rights to redistribute these changes.
65 */
66
67/*
68 * Type definitions for generic queues.
69 */
70
71#ifndef _QUEUE_H_
72#define _QUEUE_H_
73
74struct queue_entry {
75 struct queue_entry *next; /* next element */
76 struct queue_entry *prev; /* previous element */
77};
78
79typedef struct queue_entry *queue_t;
80typedef struct queue_entry queue_head_t;
81typedef struct queue_entry queue_chain_t;
82typedef struct queue_entry *queue_entry_t;
83
84#define round_queue(size) (((size)+7) & (~7))
85
86#define enqueue(queue,elt) enqueue_tail(queue, elt)
87#define dequeue(queue) dequeue_head(queue)
88
89#define enqueue_head(queue,elt) insque(elt,queue)
90#define enqueue_tail(queue,elt) insque(elt,(queue)->prev)
91#define remqueue(queue,elt) remque(elt)
92
93#define queue_init(q) ((q)->next = (q)->prev = q)
94#define queue_first(q) ((q)->next)
95#define queue_next(qc) ((qc)->next)
96#define queue_end(q, qe) ((q) == (qe))
97#define queue_empty(q) queue_end((q), queue_first(q))
98
99#define queue_enter(head, elt, type, field) { \
100 if (queue_empty((head))) { \
101 (head)->next = (queue_entry_t) elt; \
102 (head)->prev = (queue_entry_t) elt; \
103 (elt)->field.next = head; \
104 (elt)->field.prev = head; \
105 } else { \
106 register queue_entry_t prev = (head)->prev; \
107 (elt)->field.prev = prev; \
108 (elt)->field.next = head; \
109 (head)->prev = (queue_entry_t)(elt); \
110 ((type)prev)->field.next = (queue_entry_t)(elt);\
111 } \
112}
113
114#define queue_field(head, thing, type, field) \
115 (((head) == (thing)) ? (head) : &((type)(thing))->field)
116
117#define queue_remove(head, elt, type, field) { \
118 register queue_entry_t next = (elt)->field.next; \
119 register queue_entry_t prev = (elt)->field.prev; \
120 queue_field((head), next, type, field)->prev = prev; \
121 queue_field((head), prev, type, field)->next = next; \
122}
123
124#define queue_assign(to, from, type, field) { \
125 ((type)((from)->prev))->field.next = (to); \
126 ((type)((from)->next))->field.prev = (to); \
127 *to = *from; \
128}
129
130#define queue_remove_first(h, e, t, f) { \
131 e = (t) queue_first((h)); \
132 queue_remove((h), (e), t, f); \
133}
134
135#endif /* !_QUEUE_H_ */