queue.h (11732B)
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. ***REMOVED*** - see 14 * ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change 15 * 4. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 * 31 * @(#)queue.h 8.3 (Berkeley) 12/13/93 32 */ 33 34 #ifndef _QUEUE_H_ 35 #define _QUEUE_H_ 36 37 /* 38 * This file defines three types of data structures: lists, tail queues, 39 * and circular queues. 40 * 41 * A list is headed by a single forward pointer (or an array of forward 42 * pointers for a hash table header). The elements are doubly linked 43 * so that an arbitrary element can be removed without a need to 44 * traverse the list. New elements can be added to the list after 45 * an existing element or at the head of the list. A list may only be 46 * traversed in the forward direction. 47 * 48 * A tail queue is headed by a pair of pointers, one to the head of the 49 * list and the other to the tail of the list. The elements are doubly 50 * linked so that an arbitrary element can be removed without a need to 51 * traverse the list. New elements can be added to the list after 52 * an existing element, at the head of the list, or at the end of the 53 * list. A tail queue may only be traversed in the forward direction. 54 * 55 * A circle queue is headed by a pair of pointers, one to the head of the 56 * list and the other to the tail of the list. The elements are doubly 57 * linked so that an arbitrary element can be removed without a need to 58 * traverse the list. New elements can be added to the list before or after 59 * an existing element, at the head of the list, or at the end of the list. 60 * A circle queue may be traversed in either direction, but has a more 61 * complex end of list detection. 62 * 63 * For details on the use of these macros, see the queue(3) manual page. 64 */ 65 66 /* 67 * List definitions. 68 */ 69 #define LIST_HEAD(name, type) \ 70 struct name { \ 71 struct type *lh_first; /* first element */ \ 72 } 73 74 #define LIST_ENTRY(type) \ 75 struct { \ 76 struct type *le_next; /* next element */ \ 77 struct type **le_prev; /* address of previous next element */ \ 78 } 79 80 /* 81 * List functions. 82 */ 83 #define LIST_INIT(head) \ 84 { \ 85 (head)->lh_first = NULL; \ 86 } 87 88 #define LIST_INSERT_AFTER(listelm, elm, field) \ 89 { \ 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 { \ 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 { \ 107 if ((elm)->field.le_next != NULL) \ 108 (elm)->field.le_next->field.le_prev = \ 109 (elm)->field.le_prev; \ 110 *(elm)->field.le_prev = (elm)->field.le_next; \ 111 } 112 113 /* 114 * Tail queue definitions. 115 */ 116 #define TAILQ_HEAD(name, type) \ 117 struct name { \ 118 struct type *tqh_first; /* first element */ \ 119 struct type **tqh_last; /* addr of last next element */ \ 120 } 121 122 #define TAILQ_ENTRY(type) \ 123 struct { \ 124 struct type *tqe_next; /* next element */ \ 125 struct type **tqe_prev; /* address of previous next element */ \ 126 } 127 128 /* 129 * Tail queue functions. 130 */ 131 #define TAILQ_INIT(head) \ 132 { \ 133 (head)->tqh_first = NULL; \ 134 (head)->tqh_last = &(head)->tqh_first; \ 135 } 136 137 #define TAILQ_INSERT_HEAD(head, elm, field) \ 138 { \ 139 if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \ 140 (elm)->field.tqe_next->field.tqe_prev = \ 141 &(elm)->field.tqe_next; \ 142 else \ 143 (head)->tqh_last = &(elm)->field.tqe_next; \ 144 (head)->tqh_first = (elm); \ 145 (elm)->field.tqe_prev = &(head)->tqh_first; \ 146 } 147 148 #define TAILQ_INSERT_TAIL(head, elm, field) \ 149 { \ 150 (elm)->field.tqe_next = NULL; \ 151 (elm)->field.tqe_prev = (head)->tqh_last; \ 152 *(head)->tqh_last = (elm); \ 153 (head)->tqh_last = &(elm)->field.tqe_next; \ 154 } 155 156 #define TAILQ_INSERT_AFTER(head, listelm, elm, field) \ 157 { \ 158 if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL) \ 159 (elm)->field.tqe_next->field.tqe_prev = \ 160 &(elm)->field.tqe_next; \ 161 else \ 162 (head)->tqh_last = &(elm)->field.tqe_next; \ 163 (listelm)->field.tqe_next = (elm); \ 164 (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \ 165 } 166 167 #define TAILQ_REMOVE(head, elm, field) \ 168 { \ 169 if (((elm)->field.tqe_next) != NULL) \ 170 (elm)->field.tqe_next->field.tqe_prev = \ 171 (elm)->field.tqe_prev; \ 172 else \ 173 (head)->tqh_last = (elm)->field.tqe_prev; \ 174 *(elm)->field.tqe_prev = (elm)->field.tqe_next; \ 175 } 176 177 /* 178 * Circular queue definitions. 179 */ 180 #define CIRCLEQ_HEAD(name, type) \ 181 struct name { \ 182 struct type *cqh_first; /* first element */ \ 183 struct type *cqh_last; /* last element */ \ 184 } 185 186 #define CIRCLEQ_ENTRY(type) \ 187 struct { \ 188 struct type *cqe_next; /* next element */ \ 189 struct type *cqe_prev; /* previous element */ \ 190 } 191 192 /* 193 * Circular queue functions. 194 */ 195 #define CIRCLEQ_INIT(head) \ 196 { \ 197 (head)->cqh_first = (void *)(head); \ 198 (head)->cqh_last = (void *)(head); \ 199 } 200 201 #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) \ 202 { \ 203 (elm)->field.cqe_next = (listelm)->field.cqe_next; \ 204 (elm)->field.cqe_prev = (listelm); \ 205 if ((listelm)->field.cqe_next == (void *)(head)) \ 206 (head)->cqh_last = (elm); \ 207 else \ 208 (listelm)->field.cqe_next->field.cqe_prev = (elm); \ 209 (listelm)->field.cqe_next = (elm); \ 210 } 211 212 #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) \ 213 { \ 214 (elm)->field.cqe_next = (listelm); \ 215 (elm)->field.cqe_prev = (listelm)->field.cqe_prev; \ 216 if ((listelm)->field.cqe_prev == (void *)(head)) \ 217 (head)->cqh_first = (elm); \ 218 else \ 219 (listelm)->field.cqe_prev->field.cqe_next = (elm); \ 220 (listelm)->field.cqe_prev = (elm); \ 221 } 222 223 #define CIRCLEQ_INSERT_HEAD(head, elm, field) \ 224 { \ 225 (elm)->field.cqe_next = (head)->cqh_first; \ 226 (elm)->field.cqe_prev = (void *)(head); \ 227 if ((head)->cqh_last == (void *)(head)) \ 228 (head)->cqh_last = (elm); \ 229 else \ 230 (head)->cqh_first->field.cqe_prev = (elm); \ 231 (head)->cqh_first = (elm); \ 232 } 233 234 #define CIRCLEQ_INSERT_TAIL(head, elm, field) \ 235 { \ 236 (elm)->field.cqe_next = (void *)(head); \ 237 (elm)->field.cqe_prev = (head)->cqh_last; \ 238 if ((head)->cqh_first == (void *)(head)) \ 239 (head)->cqh_first = (elm); \ 240 else \ 241 (head)->cqh_last->field.cqe_next = (elm); \ 242 (head)->cqh_last = (elm); \ 243 } 244 245 #define CIRCLEQ_REMOVE(head, elm, field) \ 246 { \ 247 if ((elm)->field.cqe_next == (void *)(head)) \ 248 (head)->cqh_last = (elm)->field.cqe_prev; \ 249 else \ 250 (elm)->field.cqe_next->field.cqe_prev = \ 251 (elm)->field.cqe_prev; \ 252 if ((elm)->field.cqe_prev == (void *)(head)) \ 253 (head)->cqh_first = (elm)->field.cqe_next; \ 254 else \ 255 (elm)->field.cqe_prev->field.cqe_next = \ 256 (elm)->field.cqe_next; \ 257 } 258 #endif /* !_QUEUE_H_ */