Differential D5988 Diff 22699 swh/loader/cvs/rcsparse/queue.h

Changeset View

Standalone View

swh/loader/cvs/rcsparse/queue.h

This file was added.

				/* $NetBSD: queue.h,v 1.45 2006/03/07 17:56:00 pooka 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 circular 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 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 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.
				*
				* 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_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 functions.
				*/
				#if defined(_KERNEL) && defined(QUEUEDEBUG)
				#define QUEUEDEBUG_LIST_INSERT_HEAD(head, elm, field) \
				if ((head)->lh_first && \
				(head)->lh_first->field.le_prev != &(head)->lh_first) \
				panic("LIST_INSERT_HEAD %p %s:%d", (head), __FILE__, __LINE__);
				#define QUEUEDEBUG_LIST_OP(elm, field) \
				if ((elm)->field.le_next && \
				(elm)->field.le_next->field.le_prev != \
				&(elm)->field.le_next) \
				panic("LIST_* forw %p %s:%d", (elm), __FILE__, __LINE__);\
				if (*(elm)->field.le_prev != (elm)) \
				panic("LIST_* back %p %s:%d", (elm), __FILE__, __LINE__);
				#define QUEUEDEBUG_LIST_POSTREMOVE(elm, field) \
				(elm)->field.le_next = (void *)1L; \
				(elm)->field.le_prev = (void *)1L;
				#else
				#define QUEUEDEBUG_LIST_INSERT_HEAD(head, elm, field)
				#define QUEUEDEBUG_LIST_OP(elm, field)
				#define QUEUEDEBUG_LIST_POSTREMOVE(elm, field)
				#endif

				#define LIST_INIT(head) do { \
				(head)->lh_first = NULL; \
				} while (/CONSTCOND/0)

				#define LIST_INSERT_AFTER(listelm, elm, field) do { \
				QUEUEDEBUG_LIST_OP((listelm), 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; \
				} while (/CONSTCOND/0)

				#define LIST_INSERT_BEFORE(listelm, elm, field) do { \
				QUEUEDEBUG_LIST_OP((listelm), 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; \
				} while (/CONSTCOND/0)

				#define LIST_INSERT_HEAD(head, elm, field) do { \
				QUEUEDEBUG_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; \
				} while (/CONSTCOND/0)

				#define LIST_REMOVE(elm, field) do { \
				QUEUEDEBUG_LIST_OP((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; \
				QUEUEDEBUG_LIST_POSTREMOVE((elm), field) \
				} while (/CONSTCOND/0)

				#define LIST_FOREACH(var, head, field) \
				for ((var) = ((head)->lh_first); \
				(var); \
				(var) = ((var)->field.le_next))

				/*
				* List access methods.
				*/
				#define LIST_EMPTY(head) ((head)->lh_first == NULL)
				#define LIST_FIRST(head) ((head)->lh_first)
				#define LIST_NEXT(elm, field) ((elm)->field.le_next)


				/*
				* Singly-linked List definitions.
				*/
				#define SLIST_HEAD(name, type) \
				struct name { \
				struct type slh_first; / first element */ \
				}

				#define SLIST_HEAD_INITIALIZER(head) \
				{ NULL }

				#define SLIST_ENTRY(type) \
				struct { \
				struct type sle_next; / next element */ \
				}

				/*
				* Singly-linked List functions.
				*/
				#define SLIST_INIT(head) do { \
				(head)->slh_first = NULL; \
				} while (/CONSTCOND/0)

				#define SLIST_INSERT_AFTER(slistelm, elm, field) do { \
				(elm)->field.sle_next = (slistelm)->field.sle_next; \
				(slistelm)->field.sle_next = (elm); \
				} while (/CONSTCOND/0)

				#define SLIST_INSERT_HEAD(head, elm, field) do { \
				(elm)->field.sle_next = (head)->slh_first; \
				(head)->slh_first = (elm); \
				} while (/CONSTCOND/0)

				#define SLIST_REMOVE_HEAD(head, field) do { \
				(head)->slh_first = (head)->slh_first->field.sle_next; \
				} while (/CONSTCOND/0)

				#define SLIST_REMOVE(head, elm, type, field) do { \
				if ((head)->slh_first == (elm)) { \
				SLIST_REMOVE_HEAD((head), field); \
				} \
				else { \
				struct type *curelm = (head)->slh_first; \
				while(curelm->field.sle_next != (elm)) \
				curelm = curelm->field.sle_next; \
				curelm->field.sle_next = \
				curelm->field.sle_next->field.sle_next; \
				} \
				} while (/CONSTCOND/0)

				#define SLIST_FOREACH(var, head, field) \
				for((var) = (head)->slh_first; (var); (var) = (var)->field.sle_next)

				/*
				* Singly-linked List access methods.
				*/
				#define SLIST_EMPTY(head) ((head)->slh_first == NULL)
				#define SLIST_FIRST(head) ((head)->slh_first)
				#define SLIST_NEXT(elm, field) ((elm)->field.sle_next)


				/*
				* Singly-linked Tail queue declarations.
				*/
				#define STAILQ_HEAD(name, type) \
				struct name { \
				struct type stqh_first; / first element */ \
				struct type *stqh_last; / addr of last next element */ \
				}

				#define STAILQ_HEAD_INITIALIZER(head) \
				{ NULL, &(head).stqh_first }

				#define STAILQ_ENTRY(type) \
				struct { \
				struct type stqe_next; / next element */ \
				}

				/*
				* Singly-linked Tail queue functions.
				*/
				#define STAILQ_INIT(head) do { \
				(head)->stqh_first = NULL; \
				(head)->stqh_last = &(head)->stqh_first; \
				} while (/CONSTCOND/0)

				#define STAILQ_INSERT_HEAD(head, elm, field) do { \
				if (((elm)->field.stqe_next = (head)->stqh_first) == NULL) \
				(head)->stqh_last = &(elm)->field.stqe_next; \
				(head)->stqh_first = (elm); \
				} while (/CONSTCOND/0)

				#define STAILQ_INSERT_TAIL(head, elm, field) do { \
				(elm)->field.stqe_next = NULL; \
				*(head)->stqh_last = (elm); \
				(head)->stqh_last = &(elm)->field.stqe_next; \
				} while (/CONSTCOND/0)

				#define STAILQ_INSERT_AFTER(head, listelm, elm, field) do { \
				if (((elm)->field.stqe_next = (listelm)->field.stqe_next) == NULL)\
				(head)->stqh_last = &(elm)->field.stqe_next; \
				(listelm)->field.stqe_next = (elm); \
				} while (/CONSTCOND/0)

				#define STAILQ_REMOVE_HEAD(head, field) do { \
				if (((head)->stqh_first = (head)->stqh_first->field.stqe_next) == NULL) \
				(head)->stqh_last = &(head)->stqh_first; \
				} while (/CONSTCOND/0)

				#define STAILQ_REMOVE(head, elm, type, field) do { \
				if ((head)->stqh_first == (elm)) { \
				STAILQ_REMOVE_HEAD((head), field); \
				} else { \
				struct type *curelm = (head)->stqh_first; \
				while (curelm->field.stqe_next != (elm)) \
				curelm = curelm->field.stqe_next; \
				if ((curelm->field.stqe_next = \
				curelm->field.stqe_next->field.stqe_next) == NULL) \
				(head)->stqh_last = &(curelm)->field.stqe_next; \
				} \
				} while (/CONSTCOND/0)

				#define STAILQ_FOREACH(var, head, field) \
				for ((var) = ((head)->stqh_first); \
				(var); \
				(var) = ((var)->field.stqe_next))

				/*
				* Singly-linked Tail queue access methods.
				*/
				#define STAILQ_EMPTY(head) ((head)->stqh_first == NULL)
				#define STAILQ_FIRST(head) ((head)->stqh_first)
				#define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next)


				/*
				* Simple queue definitions.
				*/
				#define SIMPLEQ_HEAD(name, type) \
				struct name { \
				struct type sqh_first; / first element */ \
				struct type *sqh_last; / addr of last next element */ \
				}

				#define SIMPLEQ_HEAD_INITIALIZER(head) \
				{ NULL, &(head).sqh_first }

				#define SIMPLEQ_ENTRY(type) \
				struct { \
				struct type sqe_next; / next element */ \
				}

				/*
				* Simple queue functions.
				*/
				#define SIMPLEQ_INIT(head) do { \
				(head)->sqh_first = NULL; \
				(head)->sqh_last = &(head)->sqh_first; \
				} while (/CONSTCOND/0)

				#define SIMPLEQ_INSERT_HEAD(head, elm, field) do { \
				if (((elm)->field.sqe_next = (head)->sqh_first) == NULL) \
				(head)->sqh_last = &(elm)->field.sqe_next; \
				(head)->sqh_first = (elm); \
				} while (/CONSTCOND/0)

				#define SIMPLEQ_INSERT_TAIL(head, elm, field) do { \
				(elm)->field.sqe_next = NULL; \
				*(head)->sqh_last = (elm); \
				(head)->sqh_last = &(elm)->field.sqe_next; \
				} while (/CONSTCOND/0)

				#define SIMPLEQ_INSERT_AFTER(head, listelm, elm, field) do { \
				if (((elm)->field.sqe_next = (listelm)->field.sqe_next) == NULL)\
				(head)->sqh_last = &(elm)->field.sqe_next; \
				(listelm)->field.sqe_next = (elm); \
				} while (/CONSTCOND/0)

				#define SIMPLEQ_REMOVE_HEAD(head, field) do { \
				if (((head)->sqh_first = (head)->sqh_first->field.sqe_next) == NULL) \
				(head)->sqh_last = &(head)->sqh_first; \
				} while (/CONSTCOND/0)

				#define SIMPLEQ_REMOVE(head, elm, type, field) do { \
				if ((head)->sqh_first == (elm)) { \
				SIMPLEQ_REMOVE_HEAD((head), field); \
				} else { \
				struct type *curelm = (head)->sqh_first; \
				while (curelm->field.sqe_next != (elm)) \
				curelm = curelm->field.sqe_next; \
				if ((curelm->field.sqe_next = \
				curelm->field.sqe_next->field.sqe_next) == NULL) \
				(head)->sqh_last = &(curelm)->field.sqe_next; \
				} \
				} while (/CONSTCOND/0)

				#define SIMPLEQ_FOREACH(var, head, field) \
				for ((var) = ((head)->sqh_first); \
				(var); \
				(var) = ((var)->field.sqe_next))

				/*
				* Simple queue access methods.
				*/
				#define SIMPLEQ_EMPTY(head) ((head)->sqh_first == NULL)
				#define SIMPLEQ_FIRST(head) ((head)->sqh_first)
				#define SIMPLEQ_NEXT(elm, field) ((elm)->field.sqe_next)


				/*
				* Tail queue definitions.
				*/
				#define _TAILQ_HEAD(name, type, qual) \
				struct name { \
				qual type tqh_first; / first element */ \
				qual type qual tqh_last; /* addr of last next element */ \
				}
				#define TAILQ_HEAD(name, type) _TAILQ_HEAD(name, struct type,)

				#define TAILQ_HEAD_INITIALIZER(head) \
				{ NULL, &(head).tqh_first }

				#define _TAILQ_ENTRY(type, qual) \
				struct { \
				qual type tqe_next; / next element */ \
				qual type qual tqe_prev; /* address of previous next element */\
				}
				#define TAILQ_ENTRY(type) _TAILQ_ENTRY(struct type,)

				/*
				* Tail queue functions.
				*/
				#if defined(_KERNEL) && defined(QUEUEDEBUG)
				#define QUEUEDEBUG_TAILQ_INSERT_HEAD(head, elm, field) \
				if ((head)->tqh_first && \
				(head)->tqh_first->field.tqe_prev != &(head)->tqh_first) \
				panic("TAILQ_INSERT_HEAD %p %s:%d", (head), __FILE__, __LINE__);
				#define QUEUEDEBUG_TAILQ_INSERT_TAIL(head, elm, field) \
				if (*(head)->tqh_last != NULL) \
				panic("TAILQ_INSERT_TAIL %p %s:%d", (head), __FILE__, __LINE__);
				#define QUEUEDEBUG_TAILQ_OP(elm, field) \
				if ((elm)->field.tqe_next && \
				(elm)->field.tqe_next->field.tqe_prev != \
				&(elm)->field.tqe_next) \
				panic("TAILQ_* forw %p %s:%d", (elm), __FILE__, __LINE__);\
				if (*(elm)->field.tqe_prev != (elm)) \
				panic("TAILQ_* back %p %s:%d", (elm), __FILE__, __LINE__);
				#define QUEUEDEBUG_TAILQ_PREREMOVE(head, elm, field) \
				if ((elm)->field.tqe_next == NULL && \
				(head)->tqh_last != &(elm)->field.tqe_next) \
				panic("TAILQ_PREREMOVE head %p elm %p %s:%d", \
				(head), (elm), __FILE__, __LINE__);
				#define QUEUEDEBUG_TAILQ_POSTREMOVE(elm, field) \
				(elm)->field.tqe_next = (void *)1L; \
				(elm)->field.tqe_prev = (void *)1L;
				#else
				#define QUEUEDEBUG_TAILQ_INSERT_HEAD(head, elm, field)
				#define QUEUEDEBUG_TAILQ_INSERT_TAIL(head, elm, field)
				#define QUEUEDEBUG_TAILQ_OP(elm, field)
				#define QUEUEDEBUG_TAILQ_PREREMOVE(head, elm, field)
				#define QUEUEDEBUG_TAILQ_POSTREMOVE(elm, field)
				#endif

				#define TAILQ_INIT(head) do { \
				(head)->tqh_first = NULL; \
				(head)->tqh_last = &(head)->tqh_first; \
				} while (/CONSTCOND/0)

				#define TAILQ_INSERT_HEAD(head, elm, field) do { \
				QUEUEDEBUG_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; \
				} while (/CONSTCOND/0)

				#define TAILQ_INSERT_TAIL(head, elm, field) do { \
				QUEUEDEBUG_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; \
				} while (/CONSTCOND/0)

				#define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \
				QUEUEDEBUG_TAILQ_OP((listelm), 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; \
				} while (/CONSTCOND/0)

				#define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \
				QUEUEDEBUG_TAILQ_OP((listelm), 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; \
				} while (/CONSTCOND/0)

				#define TAILQ_REMOVE(head, elm, field) do { \
				QUEUEDEBUG_TAILQ_PREREMOVE((head), (elm), field) \
				QUEUEDEBUG_TAILQ_OP((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; \
				QUEUEDEBUG_TAILQ_POSTREMOVE((elm), field); \
				} while (/CONSTCOND/0)

				#define TAILQ_FOREACH(var, head, field) \
				for ((var) = ((head)->tqh_first); \
				(var); \
				(var) = ((var)->field.tqe_next))

				#define TAILQ_FOREACH_REVERSE(var, head, headname, field) \
				for ((var) = ((((struct headname )((head)->tqh_last))->tqh_last)); \
				(var); \
				(var) = ((((struct headname )((var)->field.tqe_prev))->tqh_last)))

				/*
				* Tail queue access methods.
				*/
				#define TAILQ_EMPTY(head) ((head)->tqh_first == NULL)
				#define TAILQ_FIRST(head) ((head)->tqh_first)
				#define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)

				#define TAILQ_LAST(head, headname) \
				((((struct headname )((head)->tqh_last))->tqh_last))
				#define TAILQ_PREV(elm, headname, field) \
				((((struct headname )((elm)->field.tqe_prev))->tqh_last))


				/*
				* Circular queue definitions.
				*/
				#if defined(_KERNEL) && defined(QUEUEDEBUG)
				#define QUEUEDEBUG_CIRCLEQ_HEAD(head, field) \
				if ((head)->cqh_first != (void *)(head) && \
				(head)->cqh_first->field.cqe_prev != (void *)(head)) \
				panic("CIRCLEQ head forw %p %s:%d", (head), \
				__FILE__, __LINE__); \
				if ((head)->cqh_last != (void *)(head) && \
				(head)->cqh_last->field.cqe_next != (void *)(head)) \
				panic("CIRCLEQ head back %p %s:%d", (head), \
				__FILE__, __LINE__);
				#define QUEUEDEBUG_CIRCLEQ_ELM(head, elm, field) \
				if ((elm)->field.cqe_next == (void *)(head)) { \
				if ((head)->cqh_last != (elm)) \
				panic("CIRCLEQ elm last %p %s:%d", (elm), \
				__FILE__, __LINE__); \
				} else { \
				if ((elm)->field.cqe_next->field.cqe_prev != (elm)) \
				panic("CIRCLEQ elm forw %p %s:%d", (elm), \
				__FILE__, __LINE__); \
				} \
				if ((elm)->field.cqe_prev == (void *)(head)) { \
				if ((head)->cqh_first != (elm)) \
				panic("CIRCLEQ elm first %p %s:%d", (elm), \
				__FILE__, __LINE__); \
				} else { \
				if ((elm)->field.cqe_prev->field.cqe_next != (elm)) \
				panic("CIRCLEQ elm prev %p %s:%d", (elm), \
				__FILE__, __LINE__); \
				}
				#define QUEUEDEBUG_CIRCLEQ_POSTREMOVE(elm, field) \
				(elm)->field.cqe_next = (void *)1L; \
				(elm)->field.cqe_prev = (void *)1L;
				#else
				#define QUEUEDEBUG_CIRCLEQ_HEAD(head, field)
				#define QUEUEDEBUG_CIRCLEQ_ELM(head, elm, field)
				#define QUEUEDEBUG_CIRCLEQ_POSTREMOVE(elm, field)
				#endif

				#define CIRCLEQ_HEAD(name, type) \
				struct name { \
				struct type cqh_first; / first element */ \
				struct type cqh_last; / last element */ \
				}

				#define CIRCLEQ_HEAD_INITIALIZER(head) \
				{ (void )&head, (void )&head }

				#define CIRCLEQ_ENTRY(type) \
				struct { \
				struct type cqe_next; / next element */ \
				struct type cqe_prev; / previous element */ \
				}

				/*
				* Circular queue functions.
				*/
				#define CIRCLEQ_INIT(head) do { \
				(head)->cqh_first = (void *)(head); \
				(head)->cqh_last = (void *)(head); \
				} while (/CONSTCOND/0)

				#define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do { \
				QUEUEDEBUG_CIRCLEQ_HEAD((head), field) \
				QUEUEDEBUG_CIRCLEQ_ELM((head), (listelm), 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); \
				} while (/CONSTCOND/0)

				#define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do { \
				QUEUEDEBUG_CIRCLEQ_HEAD((head), field) \
				QUEUEDEBUG_CIRCLEQ_ELM((head), (listelm), 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); \
				} while (/CONSTCOND/0)

				#define CIRCLEQ_INSERT_HEAD(head, elm, field) do { \
				QUEUEDEBUG_CIRCLEQ_HEAD((head), 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); \
				} while (/CONSTCOND/0)

				#define CIRCLEQ_INSERT_TAIL(head, elm, field) do { \
				QUEUEDEBUG_CIRCLEQ_HEAD((head), 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); \
				} while (/CONSTCOND/0)

				#define CIRCLEQ_REMOVE(head, elm, field) do { \
				QUEUEDEBUG_CIRCLEQ_HEAD((head), field) \
				QUEUEDEBUG_CIRCLEQ_ELM((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; \
				QUEUEDEBUG_CIRCLEQ_POSTREMOVE((elm), field) \
				} while (/CONSTCOND/0)

				#define CIRCLEQ_FOREACH(var, head, field) \
				for ((var) = ((head)->cqh_first); \
				(var) != (const void *)(head); \
				(var) = ((var)->field.cqe_next))

				#define CIRCLEQ_FOREACH_REVERSE(var, head, field) \
				for ((var) = ((head)->cqh_last); \
				(var) != (const void *)(head); \
				(var) = ((var)->field.cqe_prev))

				/*
				* Circular queue access methods.
				*/
				#define CIRCLEQ_EMPTY(head) ((head)->cqh_first == (void *)(head))
				#define CIRCLEQ_FIRST(head) ((head)->cqh_first)
				#define CIRCLEQ_LAST(head) ((head)->cqh_last)
				#define CIRCLEQ_NEXT(elm, field) ((elm)->field.cqe_next)
				#define CIRCLEQ_PREV(elm, field) ((elm)->field.cqe_prev)

				#define CIRCLEQ_LOOP_NEXT(head, elm, field) \
				(((elm)->field.cqe_next == (void *)(head)) \
				? ((head)->cqh_first) \
				: (elm->field.cqe_next))
				#define CIRCLEQ_LOOP_PREV(head, elm, field) \
				(((elm)->field.cqe_prev == (void *)(head)) \
				? ((head)->cqh_last) \
				: (elm->field.cqe_prev))

				#endif /* !_SYS_QUEUE_H_ */