/*
 * Copyright (c) 2001 Fenris, Inc.
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
 */

#ifndef QUEUE_H
#define QUEUE_H

/*
 * Singly-linked Tail queue definitions.
 */
#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_EMPTY(head) ((head)->stqh_first == NULL)

#define STAILQ_INIT(head) do {                                          \
        (head)->stqh_first = NULL;                                      \
        (head)->stqh_last = &(head)->stqh_first;                        \
} while (0)

#define STAILQ_FIRST(head)      ((head)->stqh_first)
#define STAILQ_LAST(head)       (*(head)->stqh_last)

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

#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 (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 (0)

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

#define STAILQ_NEXT(elm, field) ((elm)->field.stqe_next)

#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 (0)

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


#endif /* QUEUE_H */