/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
 */

/*
 * Generic doubly-linked list implementation
 */

#include <sys/list.h>
#include <sys/list_impl.h>
#include <sys/types.h>
#include <sys/sysmacros.h>
#ifdef _KERNEL
#include <sys/debug.h>
#else
#include <assert.h>
#define ASSERT(a)       assert(a)
#endif

#ifdef lint
extern list_node_t *list_d2l(list_t *list, void *obj);
#else
#define list_d2l(a, obj) ((list_node_t *)(((char *)obj) + (a)->list_offset))
#endif
#define list_object(a, node) ((void *)(((char *)node) - (a)->list_offset))
#define list_empty(a) ((a)->list_head.list_next == &(a)->list_head)

#define list_insert_after_node(list, node, object) {    \
        list_node_t *lnew = list_d2l(list, object);     \
        lnew->list_prev = (node);                       \
        lnew->list_next = (node)->list_next;            \
        (node)->list_next->list_prev = lnew;            \
        (node)->list_next = lnew;                       \
}

#define list_insert_before_node(list, node, object) {   \
        list_node_t *lnew = list_d2l(list, object);     \
        lnew->list_next = (node);                       \
        lnew->list_prev = (node)->list_prev;            \
        (node)->list_prev->list_next = lnew;            \
        (node)->list_prev = lnew;                       \
}

#define list_remove_node(node)                                  \
        (node)->list_prev->list_next = (node)->list_next;       \
        (node)->list_next->list_prev = (node)->list_prev;       \
        (node)->list_next = (node)->list_prev = NULL

void
list_create(list_t *list, size_t size, size_t offset)
{
        ASSERT(list);
        ASSERT(size > 0);
        ASSERT(size >= offset + sizeof (list_node_t));

        list->list_size = size;
        list->list_offset = offset;
        list->list_head.list_next = list->list_head.list_prev =
            &list->list_head;
}

void
list_destroy(list_t *list)
{
        list_node_t *node = &list->list_head;

        ASSERT(list);
        ASSERT(list->list_head.list_next == node);
        ASSERT(list->list_head.list_prev == node);

        node->list_next = node->list_prev = NULL;
}

void
list_insert_after(list_t *list, void *object, void *nobject)
{
        if (object == NULL) {
                list_insert_head(list, nobject);
        } else {
                list_node_t *lold = list_d2l(list, object);
                list_insert_after_node(list, lold, nobject);
        }
}

void
list_insert_before(list_t *list, void *object, void *nobject)
{
        if (object == NULL) {
                list_insert_tail(list, nobject);
        } else {
                list_node_t *lold = list_d2l(list, object);
                list_insert_before_node(list, lold, nobject);
        }
}

void
list_insert_head(list_t *list, void *object)
{
        list_node_t *lold = &list->list_head;
        list_insert_after_node(list, lold, object);
}

void
list_insert_tail(list_t *list, void *object)
{
        list_node_t *lold = &list->list_head;
        list_insert_before_node(list, lold, object);
}

void
list_remove(list_t *list, void *object)
{
        list_node_t *lold = list_d2l(list, object);
        ASSERT(!list_empty(list));
        ASSERT(lold->list_next != NULL);
        list_remove_node(lold);
}

void *
list_remove_head(list_t *list)
{
        list_node_t *head = list->list_head.list_next;
        if (head == &list->list_head)
                return (NULL);
        list_remove_node(head);
        return (list_object(list, head));
}

void *
list_remove_tail(list_t *list)
{
        list_node_t *tail = list->list_head.list_prev;
        if (tail == &list->list_head)
                return (NULL);
        list_remove_node(tail);
        return (list_object(list, tail));
}

void *
list_head(list_t *list)
{
        if (list_empty(list))
                return (NULL);
        return (list_object(list, list->list_head.list_next));
}

void *
list_tail(list_t *list)
{
        if (list_empty(list))
                return (NULL);
        return (list_object(list, list->list_head.list_prev));
}

void *
list_next(list_t *list, void *object)
{
        list_node_t *node = list_d2l(list, object);

        if (node->list_next != &list->list_head)
                return (list_object(list, node->list_next));

        return (NULL);
}

void *
list_prev(list_t *list, void *object)
{
        list_node_t *node = list_d2l(list, object);

        if (node->list_prev != &list->list_head)
                return (list_object(list, node->list_prev));

        return (NULL);
}

/*
 *  Insert src list after dst list. Empty src list thereafter.
 */
void
list_move_tail(list_t *dst, list_t *src)
{
        list_node_t *dstnode = &dst->list_head;
        list_node_t *srcnode = &src->list_head;

        ASSERT(dst->list_size == src->list_size);
        ASSERT(dst->list_offset == src->list_offset);

        if (list_empty(src))
                return;

        dstnode->list_prev->list_next = srcnode->list_next;
        srcnode->list_next->list_prev = dstnode->list_prev;
        dstnode->list_prev = srcnode->list_prev;
        srcnode->list_prev->list_next = dstnode;

        /* empty src list */
        srcnode->list_next = srcnode->list_prev = srcnode;
}

void
list_link_replace(list_node_t *lold, list_node_t *lnew)
{
        ASSERT(list_link_active(lold));
        ASSERT(!list_link_active(lnew));

        lnew->list_next = lold->list_next;
        lnew->list_prev = lold->list_prev;
        lold->list_prev->list_next = lnew;
        lold->list_next->list_prev = lnew;
        lold->list_next = lold->list_prev = NULL;
}

void
list_link_init(list_node_t *link)
{
        link->list_next = NULL;
        link->list_prev = NULL;
}

int
list_link_active(list_node_t *link)
{
        return (link->list_next != NULL);
}

int
list_is_empty(list_t *list)
{
        return (list_empty(list));
}