/* * Copyright (c) 1991, 1993 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)queue.h 8.5 (Berkeley) 8/20/94 * $FreeBSD: src/sys/sys/queue.h,v 1.38 2000/05/26 02:06:56 jake Exp $ */ #ifndef _SYS_QUEUE_H_ #define _SYS_QUEUE_H_ /* * This file defines five types of data structures: singly-linked lists, * singly-linked tail queues, lists, tail queues, and circular queues. * * A singly-linked list is headed by a single forward pointer. The elements * are singly linked for minimum space and pointer manipulation overhead at * the expense of O(n) removal for arbitrary elements. New elements can be * added to the list after an existing element or at the head of the list. * Elements being removed from the head of the list should use the explicit * macro for this purpose for optimum efficiency. A singly-linked list may * only be traversed in the forward direction. Singly-linked lists are ideal * for applications with large datasets and few or no removals or for * implementing a LIFO queue. * * A singly-linked tail queue is headed by a pair of pointers, one to the * head of the list and the other to the tail of the list. The elements are * singly linked for minimum space and pointer manipulation overhead at the * expense of O(n) removal for arbitrary elements. New elements can be added * to the list after an existing element, at the head of the list, or at the * end of the list. Elements being removed from the head of the tail queue * should use the explicit macro for this purpose for optimum efficiency. * A singly-linked tail queue may only be traversed in the forward direction. * Singly-linked tail queues are ideal for applications with large datasets * and few or no removals or for implementing a FIFO queue. * * A list is headed by a single forward pointer (or an array of forward * pointers for a hash table header). The elements are doubly linked * so that an arbitrary element can be removed without a need to * traverse the list. New elements can be added to the list before * or after an existing element or at the head of the list. A list * may only be traversed in the forward direction. * * A tail queue is headed by a pair of pointers, one to the head of the * list and the other to the tail of the list. The elements are doubly * linked so that an arbitrary element can be removed without a need to * traverse the list. New elements can be added to the list before or * after an existing element, at the head of the list, or at the end of * the list. A tail queue may be traversed in either direction. * * A circle queue is headed by a pair of pointers, one to the head of the * list and the other to the tail of the list. The elements are doubly * linked so that an arbitrary element can be removed without a need to * traverse the list. New elements can be added to the list before or after * an existing element, at the head of the list, or at the end of the list. * A circle queue may be traversed in either direction, but has a more * complex end of list detection. * * For details on the use of these macros, see the queue(3) manual page. * * * SLIST LIST STAILQ TAILQ CIRCLEQ * _HEAD + + + + + * _HEAD_INITIALIZER + + + + + * _ENTRY + + + + + * _INIT + + + + + * _EMPTY + + + + + * _FIRST + + + + + * _NEXT + + + + + * _PREV - - - + + * _LAST - - + + + * _FOREACH + + + + + * _FOREACH_REVERSE - - - + + * _INSERT_HEAD + + + + + * _INSERT_BEFORE - + - + + * _INSERT_AFTER + + + + + * _INSERT_TAIL - - + + + * _REMOVE_HEAD + - + - - * _REMOVE + + + + + * */ /* * Singly-linked List declarations. */ #define SLIST_HEAD(name, type) … #define SLIST_HEAD_INITIALIZER(head) … #define SLIST_ENTRY(type) … /* * Singly-linked List functions. */ #define SLIST_EMPTY(head) … #define SLIST_FIRST(head) … #define SLIST_FOREACH(var, head, field) … #define SLIST_INIT(head) … #define SLIST_INSERT_AFTER(slistelm, elm, field) … #define SLIST_INSERT_HEAD(head, elm, field) … #define SLIST_NEXT(elm, field) … #define SLIST_REMOVE(head, elm, type, field) … #define SLIST_REMOVE_HEAD(head, field) … /* * Singly-linked Tail queue declarations. */ #define STAILQ_HEAD(name, type) … #define STAILQ_HEAD_INITIALIZER(head) … #define STAILQ_ENTRY(type) … /* * Singly-linked Tail queue functions. */ #define STAILQ_EMPTY(head) … #define STAILQ_FIRST(head) … #define STAILQ_FOREACH(var, head, field) … #define STAILQ_INIT(head) … #define STAILQ_INSERT_AFTER(head, tqelm, elm, field) … #define STAILQ_INSERT_HEAD(head, elm, field) … #define STAILQ_INSERT_TAIL(head, elm, field) … #define STAILQ_LAST(head) … #define STAILQ_NEXT(elm, field) … #define STAILQ_REMOVE(head, elm, type, field) … #define STAILQ_REMOVE_HEAD(head, field) … #define STAILQ_REMOVE_HEAD_UNTIL(head, elm, field) … /* * List declarations. */ #define BSD_LIST_HEAD(name, type) … #define LIST_HEAD_INITIALIZER(head) … #define LIST_ENTRY(type) … /* * List functions. */ #define LIST_EMPTY(head) … #define LIST_FIRST(head) … #define LIST_FOREACH(var, head, field) … #define LIST_INIT(head) … #define LIST_INSERT_AFTER(listelm, elm, field) … #define LIST_INSERT_BEFORE(listelm, elm, field) … #define LIST_INSERT_HEAD(head, elm, field) … #define LIST_NEXT(elm, field) … #define LIST_REMOVE(elm, field) … /* * Tail queue declarations. */ #define TAILQ_HEAD(name, type) … #define TAILQ_HEAD_INITIALIZER(head) … #define TAILQ_ENTRY(type) … /* * Tail queue functions. */ #define TAILQ_EMPTY(head) … #define TAILQ_FIRST(head) … #define TAILQ_FOREACH(var, head, field) … #define TAILQ_FOREACH_REVERSE(var, head, headname, field) … #define TAILQ_INIT(head) … #define TAILQ_INSERT_AFTER(head, listelm, elm, field) … #define TAILQ_INSERT_BEFORE(listelm, elm, field) … #define TAILQ_INSERT_HEAD(head, elm, field) … #define TAILQ_INSERT_TAIL(head, elm, field) … #define TAILQ_LAST(head, headname) … #define TAILQ_NEXT(elm, field) … #define TAILQ_PREV(elm, headname, field) … #define TAILQ_REMOVE(head, elm, field) … /* * Circular queue declarations. */ #define CIRCLEQ_HEAD(name, type) … #define CIRCLEQ_HEAD_INITIALIZER(head) … #define CIRCLEQ_ENTRY(type) … /* * Circular queue functions. */ #define CIRCLEQ_EMPTY(head) … #define CIRCLEQ_FIRST(head) … #define CIRCLEQ_FOREACH(var, head, field) … #define CIRCLEQ_FOREACH_REVERSE(var, head, field) … #define CIRCLEQ_INIT(head) … #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) … #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) … #define CIRCLEQ_INSERT_HEAD(head, elm, field) … #define CIRCLEQ_INSERT_TAIL(head, elm, field) … #define CIRCLEQ_LAST(head) … #define CIRCLEQ_NEXT(elm,field) … #define CIRCLEQ_PREV(elm,field) … #define CIRCLEQ_REMOVE(head, elm, field) … #endif /* !_SYS_QUEUE_H_ */
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