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1 | /* |
2 | * Copyright (c) 1991, 1993 | |
3 | * The Regents of the University of California. All rights reserved. | |
4 | * | |
5 | * Redistribution and use in source and binary forms, with or without | |
6 | * modification, are permitted provided that the following conditions | |
7 | * are met: | |
8 | * 1. Redistributions of source code must retain the above copyright | |
9 | * notice, this list of conditions and the following disclaimer. | |
10 | * 2. Redistributions in binary form must reproduce the above copyright | |
11 | * notice, this list of conditions and the following disclaimer in the | |
12 | * documentation and/or other materials provided with the distribution. | |
13 | * 4. Neither the name of the University nor the names of its contributors | |
14 | * may be used to endorse or promote products derived from this software | |
15 | * without specific prior written permission. | |
16 | * | |
17 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND | |
18 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
19 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
20 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE | |
21 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
22 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
23 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
24 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
25 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
26 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
27 | * SUCH DAMAGE. | |
28 | * | |
29 | * @(#)queue.h 8.3 (Berkeley) 12/13/93 | |
30 | */ | |
31 | ||
32 | #ifndef _SYS_QUEUE_H | |
33 | #define _SYS_QUEUE_H 1 | |
34 | ||
35 | /* | |
36 | * This file defines three types of data structures: lists, tail queues, | |
37 | * and circular queues. | |
38 | * | |
39 | * A list is headed by a single forward pointer (or an array of forward | |
40 | * pointers for a hash table header). The elements are doubly linked | |
41 | * so that an arbitrary element can be removed without a need to | |
42 | * traverse the list. New elements can be added to the list after | |
43 | * an existing element or at the head of the list. A list may only be | |
44 | * traversed in the forward direction. | |
45 | * | |
46 | * A tail queue is headed by a pair of pointers, one to the head of the | |
47 | * list and the other to the tail of the list. The elements are doubly | |
48 | * linked so that an arbitrary element can be removed without a need to | |
49 | * traverse the list. New elements can be added to the list after | |
50 | * an existing element, at the head of the list, or at the end of the | |
51 | * list. A tail queue may only be traversed in the forward direction. | |
52 | * | |
53 | * A circle queue is headed by a pair of pointers, one to the head of the | |
54 | * list and the other to the tail of the list. The elements are doubly | |
55 | * linked so that an arbitrary element can be removed without a need to | |
56 | * traverse the list. New elements can be added to the list before or after | |
57 | * an existing element, at the head of the list, or at the end of the list. | |
58 | * A circle queue may be traversed in either direction, but has a more | |
59 | * complex end of list detection. | |
60 | * | |
61 | * For details on the use of these macros, see the queue(3) manual page. | |
62 | */ | |
63 | ||
64 | /* | |
65 | * List definitions. | |
66 | */ | |
67 | #define LIST_HEAD(name, type) \ | |
68 | struct name { \ | |
69 | struct type *lh_first; /* first element */ \ | |
70 | } | |
71 | ||
72 | #define LIST_ENTRY(type) \ | |
73 | struct { \ | |
74 | struct type *le_next; /* next element */ \ | |
75 | struct type **le_prev; /* address of previous next element */ \ | |
76 | } | |
77 | ||
78 | /* | |
79 | * List functions. | |
80 | */ | |
81 | #define LIST_INIT(head) { \ | |
82 | (head)->lh_first = NULL; \ | |
83 | } | |
84 | ||
85 | #define LIST_INSERT_AFTER(listelm, elm, field) { \ | |
86 | if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \ | |
87 | (listelm)->field.le_next->field.le_prev = \ | |
88 | &(elm)->field.le_next; \ | |
89 | (listelm)->field.le_next = (elm); \ | |
90 | (elm)->field.le_prev = &(listelm)->field.le_next; \ | |
91 | } | |
92 | ||
93 | #define LIST_INSERT_HEAD(head, elm, field) { \ | |
94 | if (((elm)->field.le_next = (head)->lh_first) != NULL) \ | |
95 | (head)->lh_first->field.le_prev = &(elm)->field.le_next;\ | |
96 | (head)->lh_first = (elm); \ | |
97 | (elm)->field.le_prev = &(head)->lh_first; \ | |
98 | } | |
99 | ||
100 | #define LIST_REMOVE(elm, field) { \ | |
101 | if ((elm)->field.le_next != NULL) \ | |
102 | (elm)->field.le_next->field.le_prev = \ | |
103 | (elm)->field.le_prev; \ | |
104 | *(elm)->field.le_prev = (elm)->field.le_next; \ | |
105 | } | |
106 | ||
107 | /* | |
108 | * Tail queue definitions. | |
109 | */ | |
110 | #define TAILQ_HEAD(name, type) \ | |
111 | struct name { \ | |
112 | struct type *tqh_first; /* first element */ \ | |
113 | struct type **tqh_last; /* addr of last next element */ \ | |
114 | } | |
115 | ||
116 | #define TAILQ_ENTRY(type) \ | |
117 | struct { \ | |
118 | struct type *tqe_next; /* next element */ \ | |
119 | struct type **tqe_prev; /* address of previous next element */ \ | |
120 | } | |
121 | ||
122 | /* | |
123 | * Tail queue functions. | |
124 | */ | |
125 | #define TAILQ_INIT(head) { \ | |
126 | (head)->tqh_first = NULL; \ | |
127 | (head)->tqh_last = &(head)->tqh_first; \ | |
128 | } | |
129 | ||
130 | #define TAILQ_INSERT_HEAD(head, elm, field) { \ | |
131 | if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \ | |
132 | (elm)->field.tqe_next->field.tqe_prev = \ | |
133 | &(elm)->field.tqe_next; \ | |
134 | else \ | |
135 | (head)->tqh_last = &(elm)->field.tqe_next; \ | |
136 | (head)->tqh_first = (elm); \ | |
137 | (elm)->field.tqe_prev = &(head)->tqh_first; \ | |
138 | } | |
139 | ||
140 | #define TAILQ_INSERT_TAIL(head, elm, field) { \ | |
141 | (elm)->field.tqe_next = NULL; \ | |
142 | (elm)->field.tqe_prev = (head)->tqh_last; \ | |
143 | *(head)->tqh_last = (elm); \ | |
144 | (head)->tqh_last = &(elm)->field.tqe_next; \ | |
145 | } | |
146 | ||
147 | #define TAILQ_INSERT_AFTER(head, listelm, elm, field) { \ | |
148 | if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\ | |
149 | (elm)->field.tqe_next->field.tqe_prev = \ | |
150 | &(elm)->field.tqe_next; \ | |
151 | else \ | |
152 | (head)->tqh_last = &(elm)->field.tqe_next; \ | |
153 | (listelm)->field.tqe_next = (elm); \ | |
154 | (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \ | |
155 | } | |
156 | ||
157 | #define TAILQ_REMOVE(head, elm, field) { \ | |
158 | if (((elm)->field.tqe_next) != NULL) \ | |
159 | (elm)->field.tqe_next->field.tqe_prev = \ | |
160 | (elm)->field.tqe_prev; \ | |
161 | else \ | |
162 | (head)->tqh_last = (elm)->field.tqe_prev; \ | |
163 | *(elm)->field.tqe_prev = (elm)->field.tqe_next; \ | |
164 | } | |
165 | ||
166 | /* | |
167 | * Circular queue definitions. | |
168 | */ | |
169 | #define CIRCLEQ_HEAD(name, type) \ | |
170 | struct name { \ | |
171 | struct type *cqh_first; /* first element */ \ | |
172 | struct type *cqh_last; /* last element */ \ | |
173 | } | |
174 | ||
175 | #define CIRCLEQ_ENTRY(type) \ | |
176 | struct { \ | |
177 | struct type *cqe_next; /* next element */ \ | |
178 | struct type *cqe_prev; /* previous element */ \ | |
179 | } | |
180 | ||
181 | /* | |
182 | * Circular queue functions. | |
183 | */ | |
184 | #define CIRCLEQ_INIT(head) { \ | |
185 | (head)->cqh_first = (void *)(head); \ | |
186 | (head)->cqh_last = (void *)(head); \ | |
187 | } | |
188 | ||
189 | #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) { \ | |
190 | (elm)->field.cqe_next = (listelm)->field.cqe_next; \ | |
191 | (elm)->field.cqe_prev = (listelm); \ | |
192 | if ((listelm)->field.cqe_next == (void *)(head)) \ | |
193 | (head)->cqh_last = (elm); \ | |
194 | else \ | |
195 | (listelm)->field.cqe_next->field.cqe_prev = (elm); \ | |
196 | (listelm)->field.cqe_next = (elm); \ | |
197 | } | |
198 | ||
199 | #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) { \ | |
200 | (elm)->field.cqe_next = (listelm); \ | |
201 | (elm)->field.cqe_prev = (listelm)->field.cqe_prev; \ | |
202 | if ((listelm)->field.cqe_prev == (void *)(head)) \ | |
203 | (head)->cqh_first = (elm); \ | |
204 | else \ | |
205 | (listelm)->field.cqe_prev->field.cqe_next = (elm); \ | |
206 | (listelm)->field.cqe_prev = (elm); \ | |
207 | } | |
208 | ||
209 | #define CIRCLEQ_INSERT_HEAD(head, elm, field) { \ | |
210 | (elm)->field.cqe_next = (head)->cqh_first; \ | |
211 | (elm)->field.cqe_prev = (void *)(head); \ | |
212 | if ((head)->cqh_last == (void *)(head)) \ | |
213 | (head)->cqh_last = (elm); \ | |
214 | else \ | |
215 | (head)->cqh_first->field.cqe_prev = (elm); \ | |
216 | (head)->cqh_first = (elm); \ | |
217 | } | |
218 | ||
219 | #define CIRCLEQ_INSERT_TAIL(head, elm, field) { \ | |
220 | (elm)->field.cqe_next = (void *)(head); \ | |
221 | (elm)->field.cqe_prev = (head)->cqh_last; \ | |
222 | if ((head)->cqh_first == (void *)(head)) \ | |
223 | (head)->cqh_first = (elm); \ | |
224 | else \ | |
225 | (head)->cqh_last->field.cqe_next = (elm); \ | |
226 | (head)->cqh_last = (elm); \ | |
227 | } | |
228 | ||
229 | #define CIRCLEQ_REMOVE(head, elm, field) { \ | |
230 | if ((elm)->field.cqe_next == (void *)(head)) \ | |
231 | (head)->cqh_last = (elm)->field.cqe_prev; \ | |
232 | else \ | |
233 | (elm)->field.cqe_next->field.cqe_prev = \ | |
234 | (elm)->field.cqe_prev; \ | |
235 | if ((elm)->field.cqe_prev == (void *)(head)) \ | |
236 | (head)->cqh_first = (elm)->field.cqe_next; \ | |
237 | else \ | |
238 | (elm)->field.cqe_prev->field.cqe_next = \ | |
239 | (elm)->field.cqe_next; \ | |
240 | } | |
241 | #endif /* sys/queue.h */ |