queue.h revision 8876
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 8.4 (Berkeley) 1/4/94 34 * $Id: queue.h,v 1.2 1994/08/02 07:53:25 davidg Exp $ 35 */ 36 37#ifndef _SYS_QUEUE_H_ 38#define _SYS_QUEUE_H_ 39 40/* 41 * This file defines three types of data structures: lists, tail queues, 42 * and circular queues. 43 * 44 * A list is headed by a single forward pointer (or an array of forward 45 * pointers for a hash table header). The elements are doubly linked 46 * so that an arbitrary element can be removed without a need to 47 * traverse the list. New elements can be added to the list after 48 * an existing element or at the head of the list. A list may only be 49 * traversed in the forward direction. 50 * 51 * A tail queue is headed by a pair of pointers, one to the head of the 52 * list and the other to the tail of the list. The elements are doubly 53 * linked so that an arbitrary element can be removed without a need to 54 * traverse the list. New elements can be added to the list after 55 * an existing element, at the head of the list, or at the end of the 56 * list. A tail queue may only be traversed in the forward direction. 57 * 58 * A circle queue is headed by a pair of pointers, one to the head of the 59 * list and the other to the tail of the list. The elements are doubly 60 * linked so that an arbitrary element can be removed without a need to 61 * traverse the list. New elements can be added to the list before or after 62 * an existing element, at the head of the list, or at the end of the list. 63 * A circle queue may be traversed in either direction, but has a more 64 * complex end of list detection. 65 * 66 * For details on the use of these macros, see the queue(3) manual page. 67 */ 68 69/* 70 * List definitions. 71 */ 72#define LIST_HEAD(name, type) \ 73struct name { \ 74 struct type *lh_first; /* first element */ \ 75} 76 77#define LIST_ENTRY(type) \ 78struct { \ 79 struct type *le_next; /* next element */ \ 80 struct type **le_prev; /* address of previous next element */ \ 81} 82 83/* 84 * List functions. 85 */ 86#define LIST_INIT(head) { \ 87 (head)->lh_first = NULL; \ 88} 89 90#define LIST_INSERT_AFTER(listelm, elm, field) { \ 91 if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \ 92 (listelm)->field.le_next->field.le_prev = \ 93 &(elm)->field.le_next; \ 94 (listelm)->field.le_next = (elm); \ 95 (elm)->field.le_prev = &(listelm)->field.le_next; \ 96} 97 98#define LIST_INSERT_HEAD(head, elm, field) { \ 99 if (((elm)->field.le_next = (head)->lh_first) != NULL) \ 100 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\ 101 (head)->lh_first = (elm); \ 102 (elm)->field.le_prev = &(head)->lh_first; \ 103} 104 105#define LIST_REMOVE(elm, field) { \ 106 if ((elm)->field.le_next != NULL) \ 107 (elm)->field.le_next->field.le_prev = \ 108 (elm)->field.le_prev; \ 109 *(elm)->field.le_prev = (elm)->field.le_next; \ 110} 111 112/* 113 * Tail queue definitions. 114 */ 115#define TAILQ_HEAD(name, type) \ 116struct name { \ 117 struct type *tqh_first; /* first element */ \ 118 struct type **tqh_last; /* addr of last next element */ \ 119} 120 121#define TAILQ_ENTRY(type) \ 122struct { \ 123 struct type *tqe_next; /* next element */ \ 124 struct type **tqe_prev; /* address of previous next element */ \ 125} 126 127/* 128 * Tail queue functions. 129 */ 130#define TAILQ_INIT(head) { \ 131 (head)->tqh_first = NULL; \ 132 (head)->tqh_last = &(head)->tqh_first; \ 133} 134 135#define TAILQ_INSERT_HEAD(head, elm, field) { \ 136 if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \ 137 (elm)->field.tqe_next->field.tqe_prev = \ 138 &(elm)->field.tqe_next; \ 139 else \ 140 (head)->tqh_last = &(elm)->field.tqe_next; \ 141 (head)->tqh_first = (elm); \ 142 (elm)->field.tqe_prev = &(head)->tqh_first; \ 143} 144 145#define TAILQ_INSERT_TAIL(head, elm, field) { \ 146 (elm)->field.tqe_next = NULL; \ 147 (elm)->field.tqe_prev = (head)->tqh_last; \ 148 *(head)->tqh_last = (elm); \ 149 (head)->tqh_last = &(elm)->field.tqe_next; \ 150} 151 152#define TAILQ_INSERT_AFTER(head, listelm, elm, field) { \ 153 if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\ 154 (elm)->field.tqe_next->field.tqe_prev = \ 155 &(elm)->field.tqe_next; \ 156 else \ 157 (head)->tqh_last = &(elm)->field.tqe_next; \ 158 (listelm)->field.tqe_next = (elm); \ 159 (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \ 160} 161 162#define TAILQ_REMOVE(head, elm, field) { \ 163 if (((elm)->field.tqe_next) != NULL) \ 164 (elm)->field.tqe_next->field.tqe_prev = \ 165 (elm)->field.tqe_prev; \ 166 else \ 167 (head)->tqh_last = (elm)->field.tqe_prev; \ 168 *(elm)->field.tqe_prev = (elm)->field.tqe_next; \ 169} 170 171/* 172 * Circular queue definitions. 173 */ 174#define CIRCLEQ_HEAD(name, type) \ 175struct name { \ 176 struct type *cqh_first; /* first element */ \ 177 struct type *cqh_last; /* last element */ \ 178} 179 180#define CIRCLEQ_ENTRY(type) \ 181struct { \ 182 struct type *cqe_next; /* next element */ \ 183 struct type *cqe_prev; /* previous element */ \ 184} 185 186/* 187 * Circular queue functions. 188 */ 189#define CIRCLEQ_INIT(head) { \ 190 (head)->cqh_first = (void *)(head); \ 191 (head)->cqh_last = (void *)(head); \ 192} 193 194#define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) { \ 195 (elm)->field.cqe_next = (listelm)->field.cqe_next; \ 196 (elm)->field.cqe_prev = (listelm); \ 197 if ((listelm)->field.cqe_next == (void *)(head)) \ 198 (head)->cqh_last = (elm); \ 199 else \ 200 (listelm)->field.cqe_next->field.cqe_prev = (elm); \ 201 (listelm)->field.cqe_next = (elm); \ 202} 203 204#define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) { \ 205 (elm)->field.cqe_next = (listelm); \ 206 (elm)->field.cqe_prev = (listelm)->field.cqe_prev; \ 207 if ((listelm)->field.cqe_prev == (void *)(head)) \ 208 (head)->cqh_first = (elm); \ 209 else \ 210 (listelm)->field.cqe_prev->field.cqe_next = (elm); \ 211 (listelm)->field.cqe_prev = (elm); \ 212} 213 214#define CIRCLEQ_INSERT_HEAD(head, elm, field) { \ 215 (elm)->field.cqe_next = (head)->cqh_first; \ 216 (elm)->field.cqe_prev = (void *)(head); \ 217 if ((head)->cqh_last == (void *)(head)) \ 218 (head)->cqh_last = (elm); \ 219 else \ 220 (head)->cqh_first->field.cqe_prev = (elm); \ 221 (head)->cqh_first = (elm); \ 222} 223 224#define CIRCLEQ_INSERT_TAIL(head, elm, field) { \ 225 (elm)->field.cqe_next = (void *)(head); \ 226 (elm)->field.cqe_prev = (head)->cqh_last; \ 227 if ((head)->cqh_first == (void *)(head)) \ 228 (head)->cqh_first = (elm); \ 229 else \ 230 (head)->cqh_last->field.cqe_next = (elm); \ 231 (head)->cqh_last = (elm); \ 232} 233 234#define CIRCLEQ_REMOVE(head, elm, field) { \ 235 if ((elm)->field.cqe_next == (void *)(head)) \ 236 (head)->cqh_last = (elm)->field.cqe_prev; \ 237 else \ 238 (elm)->field.cqe_next->field.cqe_prev = \ 239 (elm)->field.cqe_prev; \ 240 if ((elm)->field.cqe_prev == (void *)(head)) \ 241 (head)->cqh_first = (elm)->field.cqe_next; \ 242 else \ 243 (elm)->field.cqe_prev->field.cqe_next = \ 244 (elm)->field.cqe_next; \ 245} 246#endif /* !_SYS_QUEUE_H_ */ 247