172 lines
6.7 KiB
C
172 lines
6.7 KiB
C
/* $OpenBSD: queue.h,v 1.43 2015/12/28 19:38:40 millert Exp $ */
|
|
/* $NetBSD: queue.h,v 1.11 1996/05/16 05:17:14 mycroft Exp $ */
|
|
|
|
/*
|
|
* 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. 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 five types of data structures: singly-linked lists,
|
|
* lists, simple queues, tail queues and XOR simple 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 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 simple 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 to save space, so elements can only be removed from the
|
|
* head of 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 simple queue 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.
|
|
*
|
|
* An XOR simple queue is used in the same way as a regular simple queue.
|
|
* The difference is that the head structure also includes a "cookie" that
|
|
* is XOR'd with the queue pointer (first, last or next) to generate the
|
|
* real pointer value.
|
|
*
|
|
* For details on the use of these macros, see the queue(3) manual page.
|
|
*/
|
|
|
|
#if defined(QUEUE_MACRO_DEBUG) || (defined(_KERNEL) && defined(DIAGNOSTIC))
|
|
#define _Q_INVALIDATE(a) (a) = ((void *)-1)
|
|
#else
|
|
#define _Q_INVALIDATE(a)
|
|
#endif
|
|
|
|
/*
|
|
* List definitions.
|
|
*/
|
|
#define LIST_HEAD(name, type) \
|
|
struct name { \
|
|
struct type *lh_first; /* first element */ \
|
|
}
|
|
|
|
#define LIST_HEAD_INITIALIZER(head) \
|
|
{ NULL }
|
|
|
|
#define LIST_ENTRY(type) \
|
|
struct { \
|
|
struct type *le_next; /* next element */ \
|
|
struct type **le_prev; /* address of previous next element */ \
|
|
}
|
|
|
|
/*
|
|
* List access methods.
|
|
*/
|
|
#define LIST_FIRST(head) ((head)->lh_first)
|
|
#define LIST_END(head) NULL
|
|
#define LIST_EMPTY(head) (LIST_FIRST(head) == LIST_END(head))
|
|
#define LIST_NEXT(elm, field) ((elm)->field.le_next)
|
|
|
|
#define LIST_FOREACH(var, head, field) \
|
|
for((var) = LIST_FIRST(head); \
|
|
(var)!= LIST_END(head); \
|
|
(var) = LIST_NEXT(var, field))
|
|
|
|
#define LIST_FOREACH_SAFE(var, head, field, tvar) \
|
|
for ((var) = LIST_FIRST(head); \
|
|
(var) && ((tvar) = LIST_NEXT(var, field), 1); \
|
|
(var) = (tvar))
|
|
|
|
/*
|
|
* List functions.
|
|
*/
|
|
#define LIST_INIT(head) do { \
|
|
LIST_FIRST(head) = LIST_END(head); \
|
|
} while (0)
|
|
|
|
#define LIST_INSERT_AFTER(listelm, elm, field) do { \
|
|
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; \
|
|
} while (0)
|
|
|
|
#define LIST_INSERT_BEFORE(listelm, elm, field) do { \
|
|
(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; \
|
|
} while (0)
|
|
|
|
#define LIST_INSERT_HEAD(head, elm, field) do { \
|
|
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; \
|
|
} while (0)
|
|
|
|
#define LIST_REMOVE(elm, field) do { \
|
|
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; \
|
|
_Q_INVALIDATE((elm)->field.le_prev); \
|
|
_Q_INVALIDATE((elm)->field.le_next); \
|
|
} while (0)
|
|
|
|
#define LIST_REPLACE(elm, elm2, field) do { \
|
|
if (((elm2)->field.le_next = (elm)->field.le_next) != NULL) \
|
|
(elm2)->field.le_next->field.le_prev = \
|
|
&(elm2)->field.le_next; \
|
|
(elm2)->field.le_prev = (elm)->field.le_prev; \
|
|
*(elm2)->field.le_prev = (elm2); \
|
|
_Q_INVALIDATE((elm)->field.le_prev); \
|
|
_Q_INVALIDATE((elm)->field.le_next); \
|
|
} while (0)
|
|
|
|
#endif /* _SYS_QUEUE_H_ */
|