454 lines
14 KiB
C
454 lines
14 KiB
C
/*
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* Copyright (c) 1991, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)queue.h 8.5 (Berkeley) 8/20/94
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* $FreeBSD$
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*/
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#ifndef _SYS_QUEUE_H_
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#define _SYS_QUEUE_H_
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#include <machine/ansi.h> /* for __offsetof */
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/*
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* This file defines four types of data structures: singly-linked lists,
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* singly-linked tail queues, lists and tail queues.
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*
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* A singly-linked list is headed by a single forward pointer. The elements
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* are singly linked for minimum space and pointer manipulation overhead at
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* the expense of O(n) removal for arbitrary elements. New elements can be
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* added to the list after an existing element or at the head of the list.
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* Elements being removed from the head of the list should use the explicit
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* macro for this purpose for optimum efficiency. A singly-linked list may
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* only be traversed in the forward direction. Singly-linked lists are ideal
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* for applications with large datasets and few or no removals or for
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* implementing a LIFO queue.
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*
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* A singly-linked tail queue is headed by a pair of pointers, one to the
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* head of the list and the other to the tail of the list. The elements are
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* singly linked for minimum space and pointer manipulation overhead at the
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* expense of O(n) removal for arbitrary elements. New elements can be added
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* to the list after an existing element, at the head of the list, or at the
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* end of the list. Elements being removed from the head of the tail queue
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* should use the explicit macro for this purpose for optimum efficiency.
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* A singly-linked tail queue may only be traversed in the forward direction.
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* Singly-linked tail queues are ideal for applications with large datasets
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* and few or no removals or for implementing a FIFO queue.
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*
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* A list is headed by a single forward pointer (or an array of forward
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* pointers for a hash table header). The elements are doubly linked
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* so that an arbitrary element can be removed without a need to
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* traverse the list. New elements can be added to the list before
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* or after an existing element or at the head of the list. A list
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* may only be traversed in the forward direction.
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*
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* A tail queue is headed by a pair of pointers, one to the head of the
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* list and the other to the tail of the list. The elements are doubly
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* linked so that an arbitrary element can be removed without a need to
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* traverse the list. New elements can be added to the list before or
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* after an existing element, at the head of the list, or at the end of
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* the list. A tail queue may be traversed in either direction.
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*
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* For details on the use of these macros, see the queue(3) manual page.
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*
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*
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* SLIST LIST STAILQ TAILQ
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* _HEAD + + + +
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* _HEAD_INITIALIZER + + + +
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* _ENTRY + + + +
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* _INIT + + + +
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* _EMPTY + + + +
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* _FIRST + + + +
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* _NEXT + + + +
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* _PREV - - - +
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* _LAST - - + +
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* _FOREACH + + + +
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* _FOREACH_REVERSE - - - +
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* _INSERT_HEAD + + + +
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* _INSERT_BEFORE - + - +
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* _INSERT_AFTER + + + +
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* _INSERT_TAIL - - + +
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* _REMOVE_HEAD + - + -
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* _REMOVE + + + +
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*
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*/
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/*
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* Singly-linked List declarations.
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*/
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#define SLIST_HEAD(name, type) \
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struct name { \
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struct type *slh_first; /* first element */ \
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}
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#define SLIST_HEAD_INITIALIZER(head) \
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{ NULL }
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#define SLIST_ENTRY(type) \
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struct { \
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struct type *sle_next; /* next element */ \
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}
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/*
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* Singly-linked List functions.
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*/
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#define SLIST_EMPTY(head) ((head)->slh_first == NULL)
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#define SLIST_FIRST(head) ((head)->slh_first)
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#define SLIST_FOREACH(var, head, field) \
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for ((var) = SLIST_FIRST((head)); \
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(var); \
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(var) = SLIST_NEXT((var), field))
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#define SLIST_INIT(head) do { \
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SLIST_FIRST((head)) = NULL; \
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} while (0)
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#define SLIST_INSERT_AFTER(slistelm, elm, field) do { \
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SLIST_NEXT((elm), field) = SLIST_NEXT((slistelm), field); \
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SLIST_NEXT((slistelm), field) = (elm); \
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} while (0)
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#define SLIST_INSERT_HEAD(head, elm, field) do { \
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SLIST_NEXT((elm), field) = SLIST_FIRST((head)); \
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SLIST_FIRST((head)) = (elm); \
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} while (0)
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#define SLIST_NEXT(elm, field) ((elm)->field.sle_next)
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#define SLIST_REMOVE(head, elm, type, field) do { \
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if (SLIST_FIRST((head)) == (elm)) { \
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SLIST_REMOVE_HEAD((head), field); \
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} \
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else { \
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struct type *curelm = SLIST_FIRST((head)); \
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while (SLIST_NEXT(curelm, field) != (elm)) \
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curelm = SLIST_NEXT(curelm, field); \
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SLIST_NEXT(curelm, field) = \
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SLIST_NEXT(SLIST_NEXT(curelm, field), field); \
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} \
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} while (0)
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#define SLIST_REMOVE_HEAD(head, field) do { \
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SLIST_FIRST((head)) = SLIST_NEXT(SLIST_FIRST((head)), field); \
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} while (0)
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/*
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* Singly-linked Tail queue declarations.
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*/
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#define STAILQ_HEAD(name, type) \
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struct name { \
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struct type *stqh_first;/* first element */ \
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struct type **stqh_last;/* addr of last next element */ \
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}
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#define STAILQ_HEAD_INITIALIZER(head) \
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{ NULL, &(head).stqh_first }
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#define STAILQ_ENTRY(type) \
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struct { \
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struct type *stqe_next; /* next element */ \
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}
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/*
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* Singly-linked Tail queue functions.
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*/
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#define STAILQ_EMPTY(head) ((head)->stqh_first == NULL)
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#define STAILQ_FIRST(head) ((head)->stqh_first)
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#define STAILQ_FOREACH(var, head, field) \
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for((var) = STAILQ_FIRST((head)); \
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(var); \
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(var) = STAILQ_NEXT((var), field))
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#define STAILQ_INIT(head) do { \
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STAILQ_FIRST((head)) = NULL; \
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(head)->stqh_last = &STAILQ_FIRST((head)); \
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} while (0)
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#define STAILQ_INSERT_AFTER(head, tqelm, elm, field) do { \
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if ((STAILQ_NEXT((elm), field) = STAILQ_NEXT((tqelm), field)) == NULL)\
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(head)->stqh_last = &STAILQ_NEXT((elm), field); \
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STAILQ_NEXT((tqelm), field) = (elm); \
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} while (0)
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#define STAILQ_INSERT_HEAD(head, elm, field) do { \
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if ((STAILQ_NEXT((elm), field) = STAILQ_FIRST((head))) == NULL) \
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(head)->stqh_last = &STAILQ_NEXT((elm), field); \
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STAILQ_FIRST((head)) = (elm); \
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} while (0)
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#define STAILQ_INSERT_TAIL(head, elm, field) do { \
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STAILQ_NEXT((elm), field) = NULL; \
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*(head)->stqh_last = (elm); \
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(head)->stqh_last = &STAILQ_NEXT((elm), field); \
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} while (0)
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#define STAILQ_LAST(head, type, field) \
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(STAILQ_EMPTY(head) ? \
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NULL : \
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((struct type *) \
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((char *)((head)->stqh_last) - __offsetof(struct type, field))))
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#define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next)
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#define STAILQ_REMOVE(head, elm, type, field) do { \
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if (STAILQ_FIRST((head)) == (elm)) { \
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STAILQ_REMOVE_HEAD(head, field); \
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} \
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else { \
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struct type *curelm = STAILQ_FIRST((head)); \
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while (STAILQ_NEXT(curelm, field) != (elm)) \
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curelm = STAILQ_NEXT(curelm, field); \
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if ((STAILQ_NEXT(curelm, field) = \
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STAILQ_NEXT(STAILQ_NEXT(curelm, field), field)) == NULL)\
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(head)->stqh_last = &STAILQ_NEXT((curelm), field);\
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} \
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} while (0)
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#define STAILQ_REMOVE_HEAD(head, field) do { \
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if ((STAILQ_FIRST((head)) = \
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STAILQ_NEXT(STAILQ_FIRST((head)), field)) == NULL) \
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(head)->stqh_last = &STAILQ_FIRST((head)); \
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} while (0)
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#define STAILQ_REMOVE_HEAD_UNTIL(head, elm, field) do { \
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if ((STAILQ_FIRST((head)) = STAILQ_NEXT((elm), field)) == NULL) \
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(head)->stqh_last = &STAILQ_FIRST((head)); \
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} while (0)
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/*
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* List declarations.
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*/
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#define LIST_HEAD(name, type) \
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struct name { \
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struct type *lh_first; /* first element */ \
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}
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#define LIST_HEAD_INITIALIZER(head) \
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{ NULL }
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#define LIST_ENTRY(type) \
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struct { \
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struct type *le_next; /* next element */ \
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struct type **le_prev; /* address of previous next element */ \
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}
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/*
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* List functions.
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*/
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#define LIST_EMPTY(head) ((head)->lh_first == NULL)
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#define LIST_FIRST(head) ((head)->lh_first)
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#define LIST_FOREACH(var, head, field) \
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for ((var) = LIST_FIRST((head)); \
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(var); \
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(var) = LIST_NEXT((var), field))
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#define LIST_INIT(head) do { \
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LIST_FIRST((head)) = NULL; \
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} while (0)
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#define LIST_INSERT_AFTER(listelm, elm, field) do { \
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if ((LIST_NEXT((elm), field) = LIST_NEXT((listelm), field)) != NULL)\
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LIST_NEXT((listelm), field)->field.le_prev = \
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&LIST_NEXT((elm), field); \
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LIST_NEXT((listelm), field) = (elm); \
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(elm)->field.le_prev = &LIST_NEXT((listelm), field); \
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} while (0)
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#define LIST_INSERT_BEFORE(listelm, elm, field) do { \
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(elm)->field.le_prev = (listelm)->field.le_prev; \
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LIST_NEXT((elm), field) = (listelm); \
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*(listelm)->field.le_prev = (elm); \
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(listelm)->field.le_prev = &LIST_NEXT((elm), field); \
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} while (0)
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#define LIST_INSERT_HEAD(head, elm, field) do { \
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if ((LIST_NEXT((elm), field) = LIST_FIRST((head))) != NULL) \
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LIST_FIRST((head))->field.le_prev = &LIST_NEXT((elm), field);\
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LIST_FIRST((head)) = (elm); \
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(elm)->field.le_prev = &LIST_FIRST((head)); \
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} while (0)
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#define LIST_NEXT(elm, field) ((elm)->field.le_next)
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#define LIST_REMOVE(elm, field) do { \
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if (LIST_NEXT((elm), field) != NULL) \
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LIST_NEXT((elm), field)->field.le_prev = \
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(elm)->field.le_prev; \
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*(elm)->field.le_prev = LIST_NEXT((elm), field); \
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} while (0)
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/*
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* Tail queue declarations.
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*/
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#define TAILQ_HEAD(name, type) \
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struct name { \
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struct type *tqh_first; /* first element */ \
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struct type **tqh_last; /* addr of last next element */ \
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}
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#define TAILQ_HEAD_INITIALIZER(head) \
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{ NULL, &(head).tqh_first }
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#define TAILQ_ENTRY(type) \
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struct { \
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struct type *tqe_next; /* next element */ \
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struct type **tqe_prev; /* address of previous next element */ \
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}
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/*
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* Tail queue functions.
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*/
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#define TAILQ_EMPTY(head) ((head)->tqh_first == NULL)
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#define TAILQ_FIRST(head) ((head)->tqh_first)
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#define TAILQ_FOREACH(var, head, field) \
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for ((var) = TAILQ_FIRST((head)); \
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(var); \
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(var) = TAILQ_NEXT((var), field))
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#define TAILQ_FOREACH_REVERSE(var, head, headname, field) \
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for ((var) = TAILQ_LAST((head), headname); \
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(var); \
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(var) = TAILQ_PREV((var), headname, field))
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#define TAILQ_INIT(head) do { \
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TAILQ_FIRST((head)) = NULL; \
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(head)->tqh_last = &TAILQ_FIRST((head)); \
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} while (0)
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#define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \
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if ((TAILQ_NEXT((elm), field) = TAILQ_NEXT((listelm), field)) != NULL)\
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TAILQ_NEXT((elm), field)->field.tqe_prev = \
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&TAILQ_NEXT((elm), field); \
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else \
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(head)->tqh_last = &TAILQ_NEXT((elm), field); \
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TAILQ_NEXT((listelm), field) = (elm); \
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(elm)->field.tqe_prev = &TAILQ_NEXT((listelm), field); \
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} while (0)
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#define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \
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(elm)->field.tqe_prev = (listelm)->field.tqe_prev; \
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TAILQ_NEXT((elm), field) = (listelm); \
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*(listelm)->field.tqe_prev = (elm); \
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(listelm)->field.tqe_prev = &TAILQ_NEXT((elm), field); \
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} while (0)
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#define TAILQ_INSERT_HEAD(head, elm, field) do { \
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if ((TAILQ_NEXT((elm), field) = TAILQ_FIRST((head))) != NULL) \
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TAILQ_FIRST((head))->field.tqe_prev = \
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&TAILQ_NEXT((elm), field); \
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else \
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(head)->tqh_last = &TAILQ_NEXT((elm), field); \
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TAILQ_FIRST((head)) = (elm); \
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(elm)->field.tqe_prev = &TAILQ_FIRST((head)); \
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} while (0)
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#define TAILQ_INSERT_TAIL(head, elm, field) do { \
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TAILQ_NEXT((elm), field) = NULL; \
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(elm)->field.tqe_prev = (head)->tqh_last; \
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*(head)->tqh_last = (elm); \
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(head)->tqh_last = &TAILQ_NEXT((elm), field); \
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} while (0)
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#define TAILQ_LAST(head, headname) \
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(*(((struct headname *)((head)->tqh_last))->tqh_last))
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#define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
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#define TAILQ_PREV(elm, headname, field) \
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(*(((struct headname *)((elm)->field.tqe_prev))->tqh_last))
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#define TAILQ_REMOVE(head, elm, field) do { \
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if ((TAILQ_NEXT((elm), field)) != NULL) \
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TAILQ_NEXT((elm), field)->field.tqe_prev = \
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(elm)->field.tqe_prev; \
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else \
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(head)->tqh_last = (elm)->field.tqe_prev; \
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*(elm)->field.tqe_prev = TAILQ_NEXT((elm), field); \
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} while (0)
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#ifdef _KERNEL
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/*
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* XXX insque() and remque() are an old way of handling certain queues.
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* They bogusly assumes that all queue heads look alike.
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*/
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struct quehead {
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struct quehead *qh_link;
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struct quehead *qh_rlink;
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};
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#ifdef __GNUC__
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static __inline void
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insque(void *a, void *b)
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{
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struct quehead *element = (struct quehead *)a,
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*head = (struct quehead *)b;
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element->qh_link = head->qh_link;
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element->qh_rlink = head;
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head->qh_link = element;
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element->qh_link->qh_rlink = element;
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}
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static __inline void
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remque(void *a)
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{
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struct quehead *element = (struct quehead *)a;
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element->qh_link->qh_rlink = element->qh_rlink;
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element->qh_rlink->qh_link = element->qh_link;
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element->qh_rlink = 0;
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}
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#else /* !__GNUC__ */
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void insque(void *a, void *b);
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void remque(void *a);
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#endif /* __GNUC__ */
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#endif /* _KERNEL */
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#endif /* !_SYS_QUEUE_H_ */
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