/*      $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_ */