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 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)queue.h 8.5 (Berkeley) 8/20/94 34 */ 35 36#ifndef _SYS_QUEUE_H_ 37#define _SYS_QUEUE_H_ 38 39/* 40 * This file defines three types of data structures: lists, tail queues, 41 * and circular queues. 42 * 43 * A list is headed by a single forward pointer (or an array of forward 44 * pointers for a hash table header). The elements are doubly linked 45 * so that an arbitrary element can be removed without a need to 46 * traverse the list. New elements can be added to the list before 47 * or after an existing element or at the head of the list. A list 48 * may only be traversed in the forward direction. 49 * 50 * A tail queue is headed by a pair of pointers, one to the head of the 51 * list and the other to the tail of the list. The elements are doubly 52 * linked so that an arbitrary element can be removed without a need to 53 * traverse the list. New elements can be added to the list before or 54 * after an existing element, at the head of the list, or at the end of 55 * the list. A tail queue may only be traversed in the forward direction. 56 * 57 * A circle queue is headed by a pair of pointers, one to the head of the 58 * list and the other to the tail of the list. The elements are doubly 59 * linked so that an arbitrary element can be removed without a need to 60 * traverse the list. New elements can be added to the list before or after 61 * an existing element, at the head of the list, or at the end of the list. 62 * A circle queue may be traversed in either direction, but has a more 63 * complex end of list detection. 64 * 65 * For details on the use of these macros, see the queue(3) manual page. 66 */ 67 68/* 69 * List definitions. 70 */ 71#define LIST_HEAD(name, type) \ 72struct name { \ 73 struct type *lh_first; /* first element */ \ 74} 75 76#define LIST_ENTRY(type) \ 77struct { \ 78 struct type *le_next; /* next element */ \ 79 struct type **le_prev; /* address of previous next element */ \ 80} 81 82/* 83 * List functions. 84 */ 85#define LIST_INIT(head) { \ 86 (head)->lh_first = NULL; \ 87} 88 89#define LIST_INSERT_AFTER(listelm, elm, field) { \ 90 if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \ 91 (listelm)->field.le_next->field.le_prev = \ 92 &(elm)->field.le_next; \ 93 (listelm)->field.le_next = (elm); \ 94 (elm)->field.le_prev = &(listelm)->field.le_next; \ 95} 96 97#define LIST_INSERT_BEFORE(listelm, elm, field) { \ 98 (elm)->field.le_prev = (listelm)->field.le_prev; \ 99 (elm)->field.le_next = (listelm); \ 100 *(listelm)->field.le_prev = (elm); \ 101 (listelm)->field.le_prev = &(elm)->field.le_next; \ 102} 103 104#define LIST_INSERT_HEAD(head, elm, field) { \ 105 if (((elm)->field.le_next = (head)->lh_first) != NULL) \ 106 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\ 107 (head)->lh_first = (elm); \ 108 (elm)->field.le_prev = &(head)->lh_first; \ 109} 110 111#define LIST_REMOVE(elm, field) { \ 112 if ((elm)->field.le_next != NULL) \ 113 (elm)->field.le_next->field.le_prev = \ 114 (elm)->field.le_prev; \ 115 *(elm)->field.le_prev = (elm)->field.le_next; \ 116} 117 118/* 119 * Tail queue definitions. 120 */ 121#define TAILQ_HEAD(name, type) \ 122struct name { \ 123 struct type *tqh_first; /* first element */ \ 124 struct type **tqh_last; /* addr of last next element */ \ 125} 126 127#define TAILQ_ENTRY(type) \ 128struct { \ 129 struct type *tqe_next; /* next element */ \ 130 struct type **tqe_prev; /* address of previous next element */ \ 131} 132 133/* 134 * Tail queue functions. 135 */ 136#define TAILQ_INIT(head) { \ 137 (head)->tqh_first = NULL; \ 138 (head)->tqh_last = &(head)->tqh_first; \ 139} 140 141#define TAILQ_INSERT_HEAD(head, elm, field) { \ 142 if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \ 143 (head)->tqh_first->field.tqe_prev = \ 144 &(elm)->field.tqe_next; \ 145 else \ 146 (head)->tqh_last = &(elm)->field.tqe_next; \ 147 (head)->tqh_first = (elm); \ 148 (elm)->field.tqe_prev = &(head)->tqh_first; \ 149} 150 151#define TAILQ_INSERT_TAIL(head, elm, field) { \ 152 (elm)->field.tqe_next = NULL; \ 153 (elm)->field.tqe_prev = (head)->tqh_last; \ 154 *(head)->tqh_last = (elm); \ 155 (head)->tqh_last = &(elm)->field.tqe_next; \ 156} 157 158#define TAILQ_INSERT_AFTER(head, listelm, elm, field) { \ 159 if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\ 160 (elm)->field.tqe_next->field.tqe_prev = \ 161 &(elm)->field.tqe_next; \ 162 else \ 163 (head)->tqh_last = &(elm)->field.tqe_next; \ 164 (listelm)->field.tqe_next = (elm); \ 165 (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \ 166} 167 168#define TAILQ_INSERT_BEFORE(listelm, elm, field) { \ 169 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ 170 (elm)->field.tqe_next = (listelm); \ 171 *(listelm)->field.tqe_prev = (elm); \ 172 (listelm)->field.tqe_prev = &(elm)->field.tqe_next; \ 173} 174 175#define TAILQ_REMOVE(head, elm, field) { \ 176 if (((elm)->field.tqe_next) != NULL) \ 177 (elm)->field.tqe_next->field.tqe_prev = \ 178 (elm)->field.tqe_prev; \ 179 else \ 180 (head)->tqh_last = (elm)->field.tqe_prev; \ 181 *(elm)->field.tqe_prev = (elm)->field.tqe_next; \ 182} 183 184/* 185 * Circular queue definitions. 186 */ 187#define CIRCLEQ_HEAD(name, type) \ 188struct name { \ 189 struct type *cqh_first; /* first element */ \ 190 struct type *cqh_last; /* last element */ \ 191} 192 193#define CIRCLEQ_ENTRY(type) \ 194struct { \ 195 struct type *cqe_next; /* next element */ \ 196 struct type *cqe_prev; /* previous element */ \ 197} 198 199/* 200 * Circular queue functions. 201 */ 202#define CIRCLEQ_INIT(head) { \ 203 (head)->cqh_first = (void *)(head); \ 204 (head)->cqh_last = (void *)(head); \ 205} 206 207#define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) { \ 208 (elm)->field.cqe_next = (listelm)->field.cqe_next; \ 209 (elm)->field.cqe_prev = (listelm); \ 210 if ((listelm)->field.cqe_next == (void *)(head)) \ 211 (head)->cqh_last = (elm); \ 212 else \ 213 (listelm)->field.cqe_next->field.cqe_prev = (elm); \ 214 (listelm)->field.cqe_next = (elm); \ 215} 216 217#define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) { \ 218 (elm)->field.cqe_next = (listelm); \ 219 (elm)->field.cqe_prev = (listelm)->field.cqe_prev; \ 220 if ((listelm)->field.cqe_prev == (void *)(head)) \ 221 (head)->cqh_first = (elm); \ 222 else \ 223 (listelm)->field.cqe_prev->field.cqe_next = (elm); \ 224 (listelm)->field.cqe_prev = (elm); \ 225} 226 227#define CIRCLEQ_INSERT_HEAD(head, elm, field) { \ 228 (elm)->field.cqe_next = (head)->cqh_first; \ 229 (elm)->field.cqe_prev = (void *)(head); \ 230 if ((head)->cqh_last == (void *)(head)) \ 231 (head)->cqh_last = (elm); \ 232 else \ 233 (head)->cqh_first->field.cqe_prev = (elm); \ 234 (head)->cqh_first = (elm); \ 235} 236 237#define CIRCLEQ_INSERT_TAIL(head, elm, field) { \ 238 (elm)->field.cqe_next = (void *)(head); \ 239 (elm)->field.cqe_prev = (head)->cqh_last; \ 240 if ((head)->cqh_first == (void *)(head)) \ 241 (head)->cqh_first = (elm); \ 242 else \ 243 (head)->cqh_last->field.cqe_next = (elm); \ 244 (head)->cqh_last = (elm); \ 245} 246 247#define CIRCLEQ_REMOVE(head, elm, field) { \ 248 if ((elm)->field.cqe_next == (void *)(head)) \ 249 (head)->cqh_last = (elm)->field.cqe_prev; \ 250 else \ 251 (elm)->field.cqe_next->field.cqe_prev = \ 252 (elm)->field.cqe_prev; \ 253 if ((elm)->field.cqe_prev == (void *)(head)) \ 254 (head)->cqh_first = (elm)->field.cqe_next; \ 255 else \ 256 (elm)->field.cqe_prev->field.cqe_next = \ 257 (elm)->field.cqe_next; \ 258} 259#endif /* !_SYS_QUEUE_H_ */ 260