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- /*
- * 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.
- * 4. Neither the name of the University nor the names of its contributors
- * may be used to endorse or promote products derived from this software
- * without specific prior written permission.
- *
- * 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 8.3 (Berkeley) 12/13/93
- */
- #ifndef _SYS_QUEUE_H
- #define _SYS_QUEUE_H 1
- /*
- * This file defines three types of data structures: lists, tail queues,
- * and circular queues.
- *
- * 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 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 after
- * an existing element, at the head of the list, or at the end of the
- * list. A tail queue may only be traversed in the forward 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.
- */
- /*
- * List definitions.
- */
- #define LIST_HEAD(name, type) \
- struct name { \
- struct type *lh_first; /* first element */ \
- }
- #define LIST_ENTRY(type) \
- struct { \
- struct type *le_next; /* next element */ \
- struct type **le_prev; /* address of previous next element */ \
- }
- /*
- * List functions.
- */
- #define LIST_INIT(head) { \
- (head)->lh_first = NULL; \
- }
- #define LIST_INSERT_AFTER(listelm, elm, field) { \
- if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \
- (listelm)->field.le_next->field.le_prev = \
- &(elm)->field.le_next; \
- (listelm)->field.le_next = (elm); \
- (elm)->field.le_prev = &(listelm)->field.le_next; \
- }
- #define LIST_INSERT_HEAD(head, elm, field) { \
- if (((elm)->field.le_next = (head)->lh_first) != NULL) \
- (head)->lh_first->field.le_prev = &(elm)->field.le_next;\
- (head)->lh_first = (elm); \
- (elm)->field.le_prev = &(head)->lh_first; \
- }
- #define LIST_REMOVE(elm, field) { \
- if ((elm)->field.le_next != NULL) \
- (elm)->field.le_next->field.le_prev = \
- (elm)->field.le_prev; \
- *(elm)->field.le_prev = (elm)->field.le_next; \
- }
- /*
- * Tail queue definitions.
- */
- #define TAILQ_HEAD(name, type) \
- struct name { \
- struct type *tqh_first; /* first element */ \
- struct type **tqh_last; /* addr of last next element */ \
- }
- #define TAILQ_ENTRY(type) \
- struct { \
- struct type *tqe_next; /* next element */ \
- struct type **tqe_prev; /* address of previous next element */ \
- }
- /*
- * Tail queue functions.
- */
- #define TAILQ_INIT(head) { \
- (head)->tqh_first = NULL; \
- (head)->tqh_last = &(head)->tqh_first; \
- }
- #define TAILQ_INSERT_HEAD(head, elm, field) { \
- if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \
- (elm)->field.tqe_next->field.tqe_prev = \
- &(elm)->field.tqe_next; \
- else \
- (head)->tqh_last = &(elm)->field.tqe_next; \
- (head)->tqh_first = (elm); \
- (elm)->field.tqe_prev = &(head)->tqh_first; \
- }
- #define TAILQ_INSERT_TAIL(head, elm, field) { \
- (elm)->field.tqe_next = NULL; \
- (elm)->field.tqe_prev = (head)->tqh_last; \
- *(head)->tqh_last = (elm); \
- (head)->tqh_last = &(elm)->field.tqe_next; \
- }
- #define TAILQ_INSERT_AFTER(head, listelm, elm, field) { \
- if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\
- (elm)->field.tqe_next->field.tqe_prev = \
- &(elm)->field.tqe_next; \
- else \
- (head)->tqh_last = &(elm)->field.tqe_next; \
- (listelm)->field.tqe_next = (elm); \
- (elm)->field.tqe_prev = &(listelm)->field.tqe_next; \
- }
- #define TAILQ_REMOVE(head, elm, field) { \
- if (((elm)->field.tqe_next) != NULL) \
- (elm)->field.tqe_next->field.tqe_prev = \
- (elm)->field.tqe_prev; \
- else \
- (head)->tqh_last = (elm)->field.tqe_prev; \
- *(elm)->field.tqe_prev = (elm)->field.tqe_next; \
- }
- /*
- * Circular queue definitions.
- */
- #define CIRCLEQ_HEAD(name, type) \
- struct name { \
- struct type *cqh_first; /* first element */ \
- struct type *cqh_last; /* last element */ \
- }
- #define CIRCLEQ_ENTRY(type) \
- struct { \
- struct type *cqe_next; /* next element */ \
- struct type *cqe_prev; /* previous element */ \
- }
- /*
- * Circular queue functions.
- */
- #define CIRCLEQ_INIT(head) { \
- (head)->cqh_first = (void *)(head); \
- (head)->cqh_last = (void *)(head); \
- }
- #define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) { \
- (elm)->field.cqe_next = (listelm)->field.cqe_next; \
- (elm)->field.cqe_prev = (listelm); \
- if ((listelm)->field.cqe_next == (void *)(head)) \
- (head)->cqh_last = (elm); \
- else \
- (listelm)->field.cqe_next->field.cqe_prev = (elm); \
- (listelm)->field.cqe_next = (elm); \
- }
- #define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) { \
- (elm)->field.cqe_next = (listelm); \
- (elm)->field.cqe_prev = (listelm)->field.cqe_prev; \
- if ((listelm)->field.cqe_prev == (void *)(head)) \
- (head)->cqh_first = (elm); \
- else \
- (listelm)->field.cqe_prev->field.cqe_next = (elm); \
- (listelm)->field.cqe_prev = (elm); \
- }
- #define CIRCLEQ_INSERT_HEAD(head, elm, field) { \
- (elm)->field.cqe_next = (head)->cqh_first; \
- (elm)->field.cqe_prev = (void *)(head); \
- if ((head)->cqh_last == (void *)(head)) \
- (head)->cqh_last = (elm); \
- else \
- (head)->cqh_first->field.cqe_prev = (elm); \
- (head)->cqh_first = (elm); \
- }
- #define CIRCLEQ_INSERT_TAIL(head, elm, field) { \
- (elm)->field.cqe_next = (void *)(head); \
- (elm)->field.cqe_prev = (head)->cqh_last; \
- if ((head)->cqh_first == (void *)(head)) \
- (head)->cqh_first = (elm); \
- else \
- (head)->cqh_last->field.cqe_next = (elm); \
- (head)->cqh_last = (elm); \
- }
- #define CIRCLEQ_REMOVE(head, elm, field) { \
- if ((elm)->field.cqe_next == (void *)(head)) \
- (head)->cqh_last = (elm)->field.cqe_prev; \
- else \
- (elm)->field.cqe_next->field.cqe_prev = \
- (elm)->field.cqe_prev; \
- if ((elm)->field.cqe_prev == (void *)(head)) \
- (head)->cqh_first = (elm)->field.cqe_next; \
- else \
- (elm)->field.cqe_prev->field.cqe_next = \
- (elm)->field.cqe_next; \
- }
- #endif /* sys/queue.h */
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