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 * $Id: tailq.h,v 1.2 2007/06/29 23:09:57 ca Exp $ 42 * 43 * This file is a modified copy of queue.h from a BSD system: 44 * we only need tail queues here. 45 * We do not use queue.h directly because there is a conflict with 46 * some versions of that file on some OSs. 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 before or 52 * after an existing element, at the head of the list, or at the end of 53 * the list. A tail queue may be traversed in either direction. 54 */ 55 56 /* 57 * Tail queue definitions. 58 */ 59 #define SM_TAILQ_HEAD(name, type) \ 60 struct name { \ 61 struct type *tqh_first; /* first element */ \ 62 struct type **tqh_last; /* addr of last next element */ \ 63 } 64 65 #define SM_TAILQ_HEAD_INITIALIZER(head) \ 66 { NULL, &(head).tqh_first } 67 68 #define SM_TAILQ_ENTRY(type) \ 69 struct { \ 70 struct type *tqe_next; /* next element */ \ 71 struct type **tqe_prev; /* address of previous next element */ \ 72 } 73 74 /* 75 * tail queue access methods 76 */ 77 #define SM_TAILQ_FIRST(head) ((head)->tqh_first) 78 #define SM_TAILQ_END(head) NULL 79 #define SM_TAILQ_NEXT(elm, field) ((elm)->field.tqe_next) 80 #define SM_TAILQ_LAST(head, headname) \ 81 (*(((struct headname *)((head)->tqh_last))->tqh_last)) 82 /* XXX */ 83 #define SM_TAILQ_PREV(elm, headname, field) \ 84 (*(((struct headname *)((elm)->field.tqe_prev))->tqh_last)) 85 #define SM_TAILQ_EMPTY(head) \ 86 (SM_TAILQ_FIRST(head) == SM_TAILQ_END(head)) 87 88 #define SM_TAILQ_FOREACH(var, head, field) \ 89 for((var) = SM_TAILQ_FIRST(head); \ 90 (var) != SM_TAILQ_END(head); \ 91 (var) = SM_TAILQ_NEXT(var, field)) 92 93 #define SM_TAILQ_FOREACH_REVERSE(var, head, headname, field) \ 94 for((var) = SM_TAILQ_LAST(head, headname); \ 95 (var) != SM_TAILQ_END(head); \ 96 (var) = SM_TAILQ_PREV(var, headname, field)) 97 98 /* 99 * Tail queue functions. 100 */ 101 #define SM_TAILQ_INIT(head) do { \ 102 (head)->tqh_first = NULL; \ 103 (head)->tqh_last = &(head)->tqh_first; \ 104 } while (0) 105 106 #define SM_TAILQ_INSERT_HEAD(head, elm, field) do { \ 107 if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \ 108 (head)->tqh_first->field.tqe_prev = \ 109 &(elm)->field.tqe_next; \ 110 else \ 111 (head)->tqh_last = &(elm)->field.tqe_next; \ 112 (head)->tqh_first = (elm); \ 113 (elm)->field.tqe_prev = &(head)->tqh_first; \ 114 } while (0) 115 116 #define SM_TAILQ_INSERT_TAIL(head, elm, field) do { \ 117 (elm)->field.tqe_next = NULL; \ 118 (elm)->field.tqe_prev = (head)->tqh_last; \ 119 *(head)->tqh_last = (elm); \ 120 (head)->tqh_last = &(elm)->field.tqe_next; \ 121 } while (0) 122 123 #define SM_TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \ 124 if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\ 125 (elm)->field.tqe_next->field.tqe_prev = \ 126 &(elm)->field.tqe_next; \ 127 else \ 128 (head)->tqh_last = &(elm)->field.tqe_next; \ 129 (listelm)->field.tqe_next = (elm); \ 130 (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \ 131 } while (0) 132 133 #define SM_TAILQ_INSERT_BEFORE(listelm, elm, field) do { \ 134 (elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ 135 (elm)->field.tqe_next = (listelm); \ 136 *(listelm)->field.tqe_prev = (elm); \ 137 (listelm)->field.tqe_prev = &(elm)->field.tqe_next; \ 138 } while (0) 139 140 #define SM_TAILQ_REMOVE(head, elm, field) do { \ 141 if (((elm)->field.tqe_next) != NULL) \ 142 (elm)->field.tqe_next->field.tqe_prev = \ 143 (elm)->field.tqe_prev; \ 144 else \ 145 (head)->tqh_last = (elm)->field.tqe_prev; \ 146 *(elm)->field.tqe_prev = (elm)->field.tqe_next; \ 147 } while (0) 148 149 #define SM_TAILQ_REPLACE(head, elm, elm2, field) do { \ 150 if (((elm2)->field.tqe_next = (elm)->field.tqe_next) != NULL) \ 151 (elm2)->field.tqe_next->field.tqe_prev = \ 152 &(elm2)->field.tqe_next; \ 153 else \ 154 (head)->tqh_last = &(elm2)->field.tqe_next; \ 155 (elm2)->field.tqe_prev = (elm)->field.tqe_prev; \ 156 *(elm2)->field.tqe_prev = (elm2); \ 157 } while (0) 158 159 #endif /* !SM_TAILQ_H_ */ 160