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 8.3 (Berkeley) 12/13/93 34 */ 35 36 #ifndef _QUEUE_H_ 37 #define _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 after 47 * an existing element or at the head of the list. A list may only be 48 * 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 after 54 * an existing element, at the head of the list, or at the end of the 55 * 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) \ 72 struct name { \ 73 struct type *lh_first; /* first element */ \ 74 } 75 76 #define LIST_ENTRY(type) \ 77 struct { \ 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_HEAD(head, elm, field) { \ 98 if (((elm)->field.le_next = (head)->lh_first) != NULL) \ 99 (head)->lh_first->field.le_prev = &(elm)->field.le_next;\ 100 (head)->lh_first = (elm); \ 101 (elm)->field.le_prev = &(head)->lh_first; \ 102 } 103 104 #define LIST_REMOVE(elm, field) { \ 105 if ((elm)->field.le_next != NULL) \ 106 (elm)->field.le_next->field.le_prev = \ 107 (elm)->field.le_prev; \ 108 *(elm)->field.le_prev = (elm)->field.le_next; \ 109 } 110 111 /* 112 * Tail queue definitions. 113 */ 114 #define TAILQ_HEAD(name, type) \ 115 struct name { \ 116 struct type *tqh_first; /* first element */ \ 117 struct type **tqh_last; /* addr of last next element */ \ 118 } 119 120 #define TAILQ_ENTRY(type) \ 121 struct { \ 122 struct type *tqe_next; /* next element */ \ 123 struct type **tqe_prev; /* address of previous next element */ \ 124 } 125 126 /* 127 * Tail queue functions. 128 */ 129 #define TAILQ_INIT(head) { \ 130 (head)->tqh_first = NULL; \ 131 (head)->tqh_last = &(head)->tqh_first; \ 132 } 133 134 #define TAILQ_INSERT_HEAD(head, elm, field) { \ 135 if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \ 136 (elm)->field.tqe_next->field.tqe_prev = \ 137 &(elm)->field.tqe_next; \ 138 else \ 139 (head)->tqh_last = &(elm)->field.tqe_next; \ 140 (head)->tqh_first = (elm); \ 141 (elm)->field.tqe_prev = &(head)->tqh_first; \ 142 } 143 144 #define TAILQ_INSERT_TAIL(head, elm, field) { \ 145 (elm)->field.tqe_next = NULL; \ 146 (elm)->field.tqe_prev = (head)->tqh_last; \ 147 *(head)->tqh_last = (elm); \ 148 (head)->tqh_last = &(elm)->field.tqe_next; \ 149 } 150 151 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) { \ 152 if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\ 153 (elm)->field.tqe_next->field.tqe_prev = \ 154 &(elm)->field.tqe_next; \ 155 else \ 156 (head)->tqh_last = &(elm)->field.tqe_next; \ 157 (listelm)->field.tqe_next = (elm); \ 158 (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \ 159 } 160 161 #define TAILQ_REMOVE(head, elm, field) { \ 162 if (((elm)->field.tqe_next) != NULL) \ 163 (elm)->field.tqe_next->field.tqe_prev = \ 164 (elm)->field.tqe_prev; \ 165 else \ 166 (head)->tqh_last = (elm)->field.tqe_prev; \ 167 *(elm)->field.tqe_prev = (elm)->field.tqe_next; \ 168 } 169 170 /* 171 * Circular queue definitions. 172 */ 173 #define CIRCLEQ_HEAD(name, type) \ 174 struct name { \ 175 struct type *cqh_first; /* first element */ \ 176 struct type *cqh_last; /* last element */ \ 177 } 178 179 #define CIRCLEQ_ENTRY(type) \ 180 struct { \ 181 struct type *cqe_next; /* next element */ \ 182 struct type *cqe_prev; /* previous element */ \ 183 } 184 185 /* 186 * Circular queue functions. 187 */ 188 #define CIRCLEQ_INIT(head) { \ 189 (head)->cqh_first = (void *)(head); \ 190 (head)->cqh_last = (void *)(head); \ 191 } 192 193 #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) { \ 194 (elm)->field.cqe_next = (listelm)->field.cqe_next; \ 195 (elm)->field.cqe_prev = (listelm); \ 196 if ((listelm)->field.cqe_next == (void *)(head)) \ 197 (head)->cqh_last = (elm); \ 198 else \ 199 (listelm)->field.cqe_next->field.cqe_prev = (elm); \ 200 (listelm)->field.cqe_next = (elm); \ 201 } 202 203 #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) { \ 204 (elm)->field.cqe_next = (listelm); \ 205 (elm)->field.cqe_prev = (listelm)->field.cqe_prev; \ 206 if ((listelm)->field.cqe_prev == (void *)(head)) \ 207 (head)->cqh_first = (elm); \ 208 else \ 209 (listelm)->field.cqe_prev->field.cqe_next = (elm); \ 210 (listelm)->field.cqe_prev = (elm); \ 211 } 212 213 #define CIRCLEQ_INSERT_HEAD(head, elm, field) { \ 214 (elm)->field.cqe_next = (head)->cqh_first; \ 215 (elm)->field.cqe_prev = (void *)(head); \ 216 if ((head)->cqh_last == (void *)(head)) \ 217 (head)->cqh_last = (elm); \ 218 else \ 219 (head)->cqh_first->field.cqe_prev = (elm); \ 220 (head)->cqh_first = (elm); \ 221 } 222 223 #define CIRCLEQ_INSERT_TAIL(head, elm, field) { \ 224 (elm)->field.cqe_next = (void *)(head); \ 225 (elm)->field.cqe_prev = (head)->cqh_last; \ 226 if ((head)->cqh_first == (void *)(head)) \ 227 (head)->cqh_first = (elm); \ 228 else \ 229 (head)->cqh_last->field.cqe_next = (elm); \ 230 (head)->cqh_last = (elm); \ 231 } 232 233 #define CIRCLEQ_REMOVE(head, elm, field) { \ 234 if ((elm)->field.cqe_next == (void *)(head)) \ 235 (head)->cqh_last = (elm)->field.cqe_prev; \ 236 else \ 237 (elm)->field.cqe_next->field.cqe_prev = \ 238 (elm)->field.cqe_prev; \ 239 if ((elm)->field.cqe_prev == (void *)(head)) \ 240 (head)->cqh_first = (elm)->field.cqe_next; \ 241 else \ 242 (elm)->field.cqe_prev->field.cqe_next = \ 243 (elm)->field.cqe_next; \ 244 } 245 #endif /* !_QUEUE_H_ */ 246