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Diffstat (limited to 'misc/queue.h')
| -rw-r--r-- | misc/queue.h | 245 |
1 files changed, 245 insertions, 0 deletions
diff --git a/misc/queue.h b/misc/queue.h new file mode 100644 index 0000000000..65612ce6f3 --- /dev/null +++ b/misc/queue.h @@ -0,0 +1,245 @@ +/* + * 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 8.3 (Berkeley) 12/13/93 + */ + +#ifndef _QUEUE_H_ +#define _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 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 /* !_QUEUE_H_ */ |