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/*!\file sys/queue.h |
* |
*/ |
|
/* |
* 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. |
* 3. All advertising materials mentioning features or use of this software |
* must display the following acknowledgement: |
* This product includes software developed by the University of |
* California, Berkeley and its contributors. |
* 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 8.5 (Berkeley) 8/20/94 |
*/ |
|
#ifndef __SYS_QUEUE_H |
#define __SYS_QUEUE_H |
|
/* |
* 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 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 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_BEFORE(listelm, elm, field) { \ |
(elm)->field.le_prev = (listelm)->field.le_prev; \ |
(elm)->field.le_next = (listelm); \ |
*(listelm)->field.le_prev = (elm); \ |
(listelm)->field.le_prev = &(elm)->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) \ |
(head)->tqh_first->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_INSERT_BEFORE(listelm, elm, field) { \ |
(elm)->field.tqe_prev = (listelm)->field.tqe_prev; \ |
(elm)->field.tqe_next = (listelm); \ |
*(listelm)->field.tqe_prev = (elm); \ |
(listelm)->field.tqe_prev = &(elm)->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 |