[qemu.git] / sys-queue.h

/*      $NetBSD: queue.h,v 1.45.14.1 2007/07/18 20:13:24 liamjfoy Exp $ */

/*
 * Qemu version: Copy from netbsd, removed debug code, removed some of
 * the implementations.  Left in lists, tail queues and circular queues.
 */

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


/*
 * 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.
 */
#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 {                        \
        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 {                        \
        (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 {              \
        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 {                   \
        (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 {                             \
        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;                 \
} while (/*CONSTCOND*/0)

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

#define TAILQ_FOREACH_SAFE(var, head, field, next_var)                  \
        for ((var) = ((head)->tqh_first);                               \
                (var) && ((next_var) = ((var)->field.tqe_next), 1);     \
                (var) = (next_var))

#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.
 */
#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 {            \
        (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 {           \
        (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 {                      \
        (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 {                      \
        (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 {                           \
        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;                              \
} 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_ */
Commit	Line	Data
fc56ef08 BS	1	/* $NetBSD: queue.h,v 1.45.14.1 2007/07/18 20:13:24 liamjfoy Exp $ */
	2
	3	/*
	4	* Qemu version: Copy from netbsd, removed debug code, removed some of
	5	* the implementations. Left in lists, tail queues and circular queues.
	6	*/
	7
	8	/*
	9	* Copyright (c) 1991, 1993
	10	* The Regents of the University of California. All rights reserved.
	11	*
	12	* Redistribution and use in source and binary forms, with or without
	13	* modification, are permitted provided that the following conditions
	14	* are met:
	15	* 1. Redistributions of source code must retain the above copyright
	16	* notice, this list of conditions and the following disclaimer.
	17	* 2. Redistributions in binary form must reproduce the above copyright
	18	* notice, this list of conditions and the following disclaimer in the
	19	* documentation and/or other materials provided with the distribution.
	20	* 3. Neither the name of the University nor the names of its contributors
	21	* may be used to endorse or promote products derived from this software
	22	* without specific prior written permission.
	23	*
	24	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	25	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	26	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	27	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	28	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	29	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	30	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	31	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	32	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	33	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	34	* SUCH DAMAGE.
	35	*
	36	* @(#)queue.h 8.5 (Berkeley) 8/20/94
	37	*/
	38
	39	#ifndef _SYS_QUEUE_H_
	40	#define _SYS_QUEUE_H_
	41
	42	/*
	43	* This file defines three types of data structures:
	44	* lists, tail queues, and circular queues.
	45	*
	46	* A list is headed by a single forward pointer (or an array of forward
	47	* pointers for a hash table header). The elements are doubly linked
	48	* so that an arbitrary element can be removed without a need to
	49	* traverse the list. New elements can be added to the list before
	50	* or after an existing element or at the head of the list. A list
	51	* may only be traversed in the forward direction.
	52	*
	53	* A tail queue is headed by a pair of pointers, one to the head of the
	54	* list and the other to the tail of the list. The elements are doubly
	55	* linked so that an arbitrary element can be removed without a need to
	56	* traverse the list. New elements can be added to the list before or
	57	* after an existing element, at the head of the list, or at the end of
	58	* the list. A tail queue may be traversed in either direction.
	59	*
	60	* A circle queue is headed by a pair of pointers, one to the head of the
	61	* list and the other to the tail of the list. The elements are doubly
	62	* linked so that an arbitrary element can be removed without a need to
	63	* traverse the list. New elements can be added to the list before or after
	64	* an existing element, at the head of the list, or at the end of the list.
65	* A circle queue may be traversed in either direction, but has a more
66	* complex end of list detection.
67	*
68	* For details on the use of these macros, see the queue(3) manual page.
69	*/
70
71	/*
72	* List definitions.
73	*/
74	#define LIST_HEAD(name, type) \
75	struct name { \
76	struct type lh_first; / first element */ \
77	}
78
79	#define LIST_HEAD_INITIALIZER(head) \
80	{ NULL }
81
82	#define LIST_ENTRY(type) \
83	struct { \
84	struct type le_next; / next element */ \
85	struct type *le_prev; / address of previous next element */ \
86	}
87
88	/*
89	* List functions.
90	*/
91	#define LIST_INIT(head) do { \
92	(head)->lh_first = NULL; \
93	} while (/CONSTCOND/0)
94
95	#define LIST_INSERT_AFTER(listelm, elm, field) do { \
96	if (((elm)->field.le_next = (listelm)->field.le_next) != NULL) \
97	(listelm)->field.le_next->field.le_prev = \
98	&(elm)->field.le_next; \
99	(listelm)->field.le_next = (elm); \
100	(elm)->field.le_prev = &(listelm)->field.le_next; \
101	} while (/CONSTCOND/0)
102
103	#define LIST_INSERT_BEFORE(listelm, elm, field) do { \
104	(elm)->field.le_prev = (listelm)->field.le_prev; \
105	(elm)->field.le_next = (listelm); \
106	*(listelm)->field.le_prev = (elm); \
107	(listelm)->field.le_prev = &(elm)->field.le_next; \
108	} while (/CONSTCOND/0)
109
110	#define LIST_INSERT_HEAD(head, elm, field) do { \
111	if (((elm)->field.le_next = (head)->lh_first) != NULL) \
112	(head)->lh_first->field.le_prev = &(elm)->field.le_next;\
113	(head)->lh_first = (elm); \
114	(elm)->field.le_prev = &(head)->lh_first; \
115	} while (/CONSTCOND/0)
116
117	#define LIST_REMOVE(elm, field) do { \
118	if ((elm)->field.le_next != NULL) \
119	(elm)->field.le_next->field.le_prev = \
120	(elm)->field.le_prev; \
121	*(elm)->field.le_prev = (elm)->field.le_next; \
122	} while (/CONSTCOND/0)
123
124	#define LIST_FOREACH(var, head, field) \
125	for ((var) = ((head)->lh_first); \
126	(var); \
127	(var) = ((var)->field.le_next))
128
129	/*
130	* List access methods.
131	*/
132	#define LIST_EMPTY(head) ((head)->lh_first == NULL)
133	#define LIST_FIRST(head) ((head)->lh_first)
134	#define LIST_NEXT(elm, field) ((elm)->field.le_next)
135
136
137	/*
138	* Tail queue definitions.
139	*/
140	#define _TAILQ_HEAD(name, type, qual) \
141	struct name { \
142	qual type tqh_first; / first element */ \
143	qual type qual tqh_last; /* addr of last next element */ \
144	}
145	#define TAILQ_HEAD(name, type) _TAILQ_HEAD(name, struct type,)
146
147	#define TAILQ_HEAD_INITIALIZER(head) \
148	{ NULL, &(head).tqh_first }
149
150	#define _TAILQ_ENTRY(type, qual) \
151	struct { \
152	qual type tqe_next; / next element */ \
153	qual type qual tqe_prev; /* address of previous next element */\
154	}
155	#define TAILQ_ENTRY(type) _TAILQ_ENTRY(struct type,)
156
157	/*
158	* Tail queue functions.
159	*/
160	#define TAILQ_INIT(head) do { \
161	(head)->tqh_first = NULL; \
162	(head)->tqh_last = &(head)->tqh_first; \
163	} while (/CONSTCOND/0)
164
165	#define TAILQ_INSERT_HEAD(head, elm, field) do { \
166	if (((elm)->field.tqe_next = (head)->tqh_first) != NULL) \
167	(head)->tqh_first->field.tqe_prev = \
168	&(elm)->field.tqe_next; \
169	else \
170	(head)->tqh_last = &(elm)->field.tqe_next; \
171	(head)->tqh_first = (elm); \
172	(elm)->field.tqe_prev = &(head)->tqh_first; \
173	} while (/CONSTCOND/0)
174
175	#define TAILQ_INSERT_TAIL(head, elm, field) do { \
176	(elm)->field.tqe_next = NULL; \
177	(elm)->field.tqe_prev = (head)->tqh_last; \
178	*(head)->tqh_last = (elm); \
179	(head)->tqh_last = &(elm)->field.tqe_next; \
180	} while (/CONSTCOND/0)
181
182	#define TAILQ_INSERT_AFTER(head, listelm, elm, field) do { \
183	if (((elm)->field.tqe_next = (listelm)->field.tqe_next) != NULL)\
184	(elm)->field.tqe_next->field.tqe_prev = \
185	&(elm)->field.tqe_next; \
186	else \
187	(head)->tqh_last = &(elm)->field.tqe_next; \
188	(listelm)->field.tqe_next = (elm); \
189	(elm)->field.tqe_prev = &(listelm)->field.tqe_next; \
190	} while (/CONSTCOND/0)
191
192	#define TAILQ_INSERT_BEFORE(listelm, elm, field) do { \
193	(elm)->field.tqe_prev = (listelm)->field.tqe_prev; \
194	(elm)->field.tqe_next = (listelm); \
195	*(listelm)->field.tqe_prev = (elm); \
196	(listelm)->field.tqe_prev = &(elm)->field.tqe_next; \
197	} while (/CONSTCOND/0)
198
199	#define TAILQ_REMOVE(head, elm, field) do { \
200	if (((elm)->field.tqe_next) != NULL) \
201	(elm)->field.tqe_next->field.tqe_prev = \
202	(elm)->field.tqe_prev; \
203	else \
204	(head)->tqh_last = (elm)->field.tqe_prev; \
205	*(elm)->field.tqe_prev = (elm)->field.tqe_next; \
206	} while (/CONSTCOND/0)
207
208	#define TAILQ_FOREACH(var, head, field) \
209	for ((var) = ((head)->tqh_first); \
210	(var); \
211	(var) = ((var)->field.tqe_next))
212
213	#define TAILQ_FOREACH_SAFE(var, head, field, next_var) \
214	for ((var) = ((head)->tqh_first); \
215	(var) && ((next_var) = ((var)->field.tqe_next), 1); \
216	(var) = (next_var))
217
218	#define TAILQ_FOREACH_REVERSE(var, head, headname, field) \
219	for ((var) = ((((struct headname )((head)->tqh_last))->tqh_last)); \
220	(var); \
221	(var) = ((((struct headname )((var)->field.tqe_prev))->tqh_last)))
222
223	/*
224	* Tail queue access methods.
225	*/
226	#define TAILQ_EMPTY(head) ((head)->tqh_first == NULL)
227	#define TAILQ_FIRST(head) ((head)->tqh_first)
228	#define TAILQ_NEXT(elm, field) ((elm)->field.tqe_next)
229
230	#define TAILQ_LAST(head, headname) \
231	((((struct headname )((head)->tqh_last))->tqh_last))
232	#define TAILQ_PREV(elm, headname, field) \
233	((((struct headname )((elm)->field.tqe_prev))->tqh_last))
234
235
236	/*
237	* Circular queue definitions.
238	*/
239	#define CIRCLEQ_HEAD(name, type) \
240	struct name { \
241	struct type cqh_first; / first element */ \
242	struct type cqh_last; / last element */ \
243	}
244
245	#define CIRCLEQ_HEAD_INITIALIZER(head) \
246	{ (void )&head, (void )&head }
247
248	#define CIRCLEQ_ENTRY(type) \
249	struct { \
250	struct type cqe_next; / next element */ \
251	struct type cqe_prev; / previous element */ \
252	}
253
254	/*
255	* Circular queue functions.
256	*/
257	#define CIRCLEQ_INIT(head) do { \
258	(head)->cqh_first = (void *)(head); \
259	(head)->cqh_last = (void *)(head); \
260	} while (/CONSTCOND/0)
261
262	#define CIRCLEQ_INSERT_AFTER(head, listelm, elm, field) do { \
263	(elm)->field.cqe_next = (listelm)->field.cqe_next; \
264	(elm)->field.cqe_prev = (listelm); \
265	if ((listelm)->field.cqe_next == (void *)(head)) \
266	(head)->cqh_last = (elm); \
267	else \
268	(listelm)->field.cqe_next->field.cqe_prev = (elm); \
269	(listelm)->field.cqe_next = (elm); \
270	} while (/CONSTCOND/0)
271
272	#define CIRCLEQ_INSERT_BEFORE(head, listelm, elm, field) do { \
273	(elm)->field.cqe_next = (listelm); \
274	(elm)->field.cqe_prev = (listelm)->field.cqe_prev; \
275	if ((listelm)->field.cqe_prev == (void *)(head)) \
276	(head)->cqh_first = (elm); \
277	else \
278	(listelm)->field.cqe_prev->field.cqe_next = (elm); \
279	(listelm)->field.cqe_prev = (elm); \
280	} while (/CONSTCOND/0)
281
282	#define CIRCLEQ_INSERT_HEAD(head, elm, field) do { \
283	(elm)->field.cqe_next = (head)->cqh_first; \
284	(elm)->field.cqe_prev = (void *)(head); \
285	if ((head)->cqh_last == (void *)(head)) \
286	(head)->cqh_last = (elm); \
287	else \
288	(head)->cqh_first->field.cqe_prev = (elm); \
289	(head)->cqh_first = (elm); \
290	} while (/CONSTCOND/0)
291
292	#define CIRCLEQ_INSERT_TAIL(head, elm, field) do { \
293	(elm)->field.cqe_next = (void *)(head); \
294	(elm)->field.cqe_prev = (head)->cqh_last; \
295	if ((head)->cqh_first == (void *)(head)) \
296	(head)->cqh_first = (elm); \
297	else \
298	(head)->cqh_last->field.cqe_next = (elm); \
299	(head)->cqh_last = (elm); \
300	} while (/CONSTCOND/0)
301
302	#define CIRCLEQ_REMOVE(head, elm, field) do { \
303	if ((elm)->field.cqe_next == (void *)(head)) \
304	(head)->cqh_last = (elm)->field.cqe_prev; \
305	else \
306	(elm)->field.cqe_next->field.cqe_prev = \
307	(elm)->field.cqe_prev; \
308	if ((elm)->field.cqe_prev == (void *)(head)) \
309	(head)->cqh_first = (elm)->field.cqe_next; \
310	else \
311	(elm)->field.cqe_prev->field.cqe_next = \
312	(elm)->field.cqe_next; \
313	} while (/CONSTCOND/0)
314
315	#define CIRCLEQ_FOREACH(var, head, field) \
316	for ((var) = ((head)->cqh_first); \
317	(var) != (const void *)(head); \
318	(var) = ((var)->field.cqe_next))
319
320	#define CIRCLEQ_FOREACH_REVERSE(var, head, field) \
321	for ((var) = ((head)->cqh_last); \
322	(var) != (const void *)(head); \
323	(var) = ((var)->field.cqe_prev))
324
325	/*
326	* Circular queue access methods.
327	*/
328	#define CIRCLEQ_EMPTY(head) ((head)->cqh_first == (void *)(head))
329	#define CIRCLEQ_FIRST(head) ((head)->cqh_first)
330	#define CIRCLEQ_LAST(head) ((head)->cqh_last)
331	#define CIRCLEQ_NEXT(elm, field) ((elm)->field.cqe_next)
332	#define CIRCLEQ_PREV(elm, field) ((elm)->field.cqe_prev)
333
334	#define CIRCLEQ_LOOP_NEXT(head, elm, field) \
335	(((elm)->field.cqe_next == (void *)(head)) \
336	? ((head)->cqh_first) \
337	: (elm->field.cqe_next))
338	#define CIRCLEQ_LOOP_PREV(head, elm, field) \
339	(((elm)->field.cqe_prev == (void *)(head)) \
340	? ((head)->cqh_last) \
341	: (elm->field.cqe_prev))
342
343	#endif /* !_SYS_QUEUE_H_ */