1 /* $OpenBSD: queue.h,v 1.30 2005/10/25 06:37:47 otto Exp $ */ 2 /* $NetBSD: queue.h,v 1.11 1996/05/16 05:17:14 mycroft Exp $ */ 3 4 /* 5 * Copyright (c) 1991, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * @(#)queue.h 8.5 (Berkeley) 8/20/94 33 */ 34 35 #ifndef SM_TAILQ_H_ 36 #define SM_TAILQ_H_ 37 38 #pragma ident "%Z%%M% %I% %E% SMI" 39 40 /* 41 * This file is a modified copy of queue.h from a BSD system: 42 * we only need tail queues here. 43 * 44 * A tail queue is headed by a pair of pointers, one to the head of the 45 * list and the other to the tail of the list. The elements are doubly 46 * linked so that an arbitrary element can be removed without a need to 47 * traverse the list. New elements can be added to the list before or 48 * after an existing element, at the head of the list, or at the end of 49 * the list. A tail queue may be traversed in either direction. 50 */ 51 52 /* 53 * Tail queue definitions. 54 */ 55 #define SM_TAILQ_HEAD(name, type) \ 56 struct name { \ 57 struct type *tqh_first; /* first element */ \ 58 struct type **tqh_last; /* addr of last next element */ \ 59 } 60 61 #define SM_TAILQ_HEAD_INITIALIZER(head) \ 62 { NULL, &(head).tqh_first } 63 64 #define SM_TAILQ_ENTRY(type) \ 65 struct { \ 66 struct type *tqe_next; /* next element */ \ 67 struct type **tqe_prev; /* address of previous next element */ \ 68 } 69 70 /* 71 * tail queue access methods 72 */ 73 #define SM_TAILQ_FIRST(head) ((head)->tqh_first) 74 #define SM_TAILQ_END(head) NULL 75 #define SM_TAILQ_NEXT(elm, field) ((elm)->field.tqe_next) 76 #define SM_TAILQ_LAST(head, headname) \ 77 (*(((struct headname *)((head)->tqh_last))->tqh_last)) 78 /* XXX */ 79 #define SM_TAILQ_PREV(elm, headname, field) \ 80 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last)) 81 #define SM_TAILQ_EMPTY(head) \ 82 (SM_TAILQ_FIRST(head) == SM_TAILQ_END(head)) 83 84 #define SM_TAILQ_FOREACH(var, head, field) \ 85 for((var) = SM_TAILQ_FIRST(head); \ 86 (var) != SM_TAILQ_END(head); \ 87 (var) = SM_TAILQ_NEXT(var, field)) 88 89 #define SM_TAILQ_FOREACH_REVERSE(var, head, headname, field) \ 90 for((var) = SM_TAILQ_LAST(head, headname); \ 91 (var) != SM_TAILQ_END(head); \ 92 (var) = SM_TAILQ_PREV(var, headname, field)) 93 94 /* 95 * Tail queue functions. 96 */ 97 #define SM_TAILQ_INIT(head) do { \ 98 (head)->tqh_first = NULL; \ 99 (head)->tqh_last = &(head)->tqh_first; \ 100 } while (0) 101 102 #define SM_TAILQ_INSERT_HEAD(head, elm, field) do { \ 103 if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \ 104 (head)->tqh_first->field.tqe_prev = \ 105 &(elm)->field.tqe_next; \ 106 else \ 107 (head)->tqh_last = &(elm)->field.tqe_next; \ 108 (head)->tqh_first = (elm); \ 109 (elm)->field.tqe_prev = &(head)->tqh_first; \ 110 } while (0) 111 112 #define SM_TAILQ_INSERT_TAIL(head, elm, field) do { \ 113 (elm)->field.tqe_next = NULL; \ 114 (elm)->field.tqe_prev = (head)->tqh_last; \ 115 *(head)->tqh_last = (elm); \ 116 (head)->tqh_last = &(elm)->field.tqe_next; \ 117 } while (0) 118 119 #define SM_TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \ 120 if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\ 121 (elm)->field.tqe_next->field.tqe_prev = \ 122 &(elm)->field.tqe_next; \ 123 else \ 124 (head)->tqh_last = &(elm)->field.tqe_next; \ 125 (listelm)->field.tqe_next = (elm); \ 126 (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \ 127 } while (0) 128 129 #define SM_TAILQ_INSERT_BEFORE(listelm, elm, field) do { \ 130 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ 131 (elm)->field.tqe_next = (listelm); \ 132 *(listelm)->field.tqe_prev = (elm); \ 133 (listelm)->field.tqe_prev = &(elm)->field.tqe_next; \ 134 } while (0) 135 136 #define SM_TAILQ_REMOVE(head, elm, field) do { \ 137 if (((elm)->field.tqe_next) != NULL) \ 138 (elm)->field.tqe_next->field.tqe_prev = \ 139 (elm)->field.tqe_prev; \ 140 else \ 141 (head)->tqh_last = (elm)->field.tqe_prev; \ 142 *(elm)->field.tqe_prev = (elm)->field.tqe_next; \ 143 } while (0) 144 145 #define SM_TAILQ_REPLACE(head, elm, elm2, field) do { \ 146 if (((elm2)->field.tqe_next = (elm)->field.tqe_next) != NULL) \ 147 (elm2)->field.tqe_next->field.tqe_prev = \ 148 &(elm2)->field.tqe_next; \ 149 else \ 150 (head)->tqh_last = &(elm2)->field.tqe_next; \ 151 (elm2)->field.tqe_prev = (elm)->field.tqe_prev; \ 152 *(elm2)->field.tqe_prev = (elm2); \ 153 } while (0) 154 155 #endif /* !SM_TAILQ_H_ */ 156