/*-
 * Copyright (c) 2010 Isilon Systems, Inc.
 * Copyright (c) 2010 iX Systems, Inc.
 * Copyright (c) 2010 Panasas, Inc.
 * Copyright (c) 2013, 2014 Mellanox Technologies, Ltd.
 * 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 unmodified, 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 ``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 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 _LINUXKPI_LINUX_RBTREE_H_
#define _LINUXKPI_LINUX_RBTREE_H_

#ifndef _STANDALONE
#include <sys/stddef.h>
#endif

#include <sys/types.h>
#include <sys/tree.h>

struct rb_node {
        RB_ENTRY(rb_node)       __entry;
};
#define rb_left         __entry.rbe_link[_RB_L]
#define rb_right        __entry.rbe_link[_RB_R]

/*
 * We provide a false structure that has the same bit pattern as tree.h
 * presents so it matches the member names expected by linux.
 */
struct rb_root {
        struct  rb_node *rb_node;
};

struct rb_root_cached {
        struct rb_root rb_root;
        struct rb_node *rb_leftmost;
};

/*
 * In linux all of the comparisons are done by the caller.
 */
int panic_cmp(struct rb_node *one, struct rb_node *two);

RB_HEAD(linux_root, rb_node);
RB_PROTOTYPE(linux_root, rb_node, __entry, panic_cmp);

#define rb_parent(r)    RB_PARENT(r, __entry)
#define rb_entry(ptr, type, member)     container_of(ptr, type, member)
#define rb_entry_safe(ptr, type, member) \
        ((ptr) != NULL ? rb_entry(ptr, type, member) : NULL)

#define RB_EMPTY_ROOT(root)     ((root)->rb_node == NULL)
#define RB_EMPTY_NODE(node)     (RB_PARENT(node, __entry) == node)
#define RB_CLEAR_NODE(node)     RB_SET_PARENT(node, node, __entry)

#define rb_insert_color(node, root) do {                                \
        if (rb_parent(node))                                            \
                linux_root_RB_INSERT_COLOR((struct linux_root *)(root), \
                    rb_parent(node), (node));                           \
} while (0)
#define rb_erase(node, root)                                            \
        linux_root_RB_REMOVE((struct linux_root *)(root), (node))
#define rb_next(node)   RB_NEXT(linux_root, NULL, (node))
#define rb_prev(node)   RB_PREV(linux_root, NULL, (node))
#define rb_first(root)  RB_MIN(linux_root, (struct linux_root *)(root))
#define rb_last(root)   RB_MAX(linux_root, (struct linux_root *)(root))
#define rb_first_cached(root)   (root)->rb_leftmost

static inline struct rb_node *
__rb_deepest_left(struct rb_node *node)
{
        struct rb_node *parent = NULL;
        while (node != NULL) {
                parent = node;
                if (RB_LEFT(node, __entry))
                        node = RB_LEFT(node, __entry);
                else
                        node = RB_RIGHT(node, __entry);
        }
        return (parent);
}

static inline struct rb_node *
rb_next_postorder(const struct rb_node *node)
{
        struct rb_node *parent =
            RB_PARENT(__DECONST(struct rb_node *, node), __entry);
        /* left -> right, right -> root */
        if (parent != NULL &&
            (node == RB_LEFT(parent, __entry)) &&
            (RB_RIGHT(parent, __entry)))
                return (__rb_deepest_left(RB_RIGHT(parent, __entry)));
        else
                return (parent);
}

#define rbtree_postorder_for_each_entry_safe(x, y, head, member)        \
        for ((x) = rb_entry_safe(__rb_deepest_left((head)->rb_node),    \
            __typeof(*x), member);                                      \
            ((x) != NULL) && ((y) =                                     \
            rb_entry_safe(rb_next_postorder(&x->member), typeof(*x), member), 1); \
            (x) = (y))

static inline void
rb_link_node(struct rb_node *node, struct rb_node *parent,
    struct rb_node **rb_link)
{
        RB_SET(node, parent, __entry);
        *rb_link = node;
}

static inline void
rb_replace_node(struct rb_node *victim, struct rb_node *new,
    struct rb_root *root)
{

        RB_SWAP_CHILD((struct linux_root *)root, rb_parent(victim),
            victim, new, __entry);
        if (RB_LEFT(victim, __entry))
                RB_SET_PARENT(RB_LEFT(victim, __entry), new, __entry);
        if (RB_RIGHT(victim, __entry))
                RB_SET_PARENT(RB_RIGHT(victim, __entry), new, __entry);
        *new = *victim;
}

static inline void
rb_insert_color_cached(struct rb_node *node, struct rb_root_cached *root,
    bool leftmost)
{
        if (rb_parent(node))
                linux_root_RB_INSERT_COLOR((struct linux_root *)&root->rb_root,
                    rb_parent(node), node);
        if (leftmost)
                root->rb_leftmost = node;
}

static inline struct rb_node *
rb_erase_cached(struct rb_node *node, struct rb_root_cached *root)
{
        struct rb_node *retval;

        if (node == root->rb_leftmost)
                retval = root->rb_leftmost = linux_root_RB_NEXT(node);
        else
                retval = NULL;
        linux_root_RB_REMOVE((struct linux_root *)&root->rb_root, node);
        return (retval);
}

static inline void
rb_replace_node_cached(struct rb_node *old, struct rb_node *new,
    struct rb_root_cached *root)
{
        rb_replace_node(old, new, &root->rb_root);
        if (root->rb_leftmost == old)
                root->rb_leftmost = new;
}

static inline struct rb_node *
rb_add_cached(struct rb_node *node, struct rb_root_cached *tree,
    bool (*less)(struct rb_node *, const struct rb_node *))
{
        struct rb_node **link = &tree->rb_root.rb_node;
        struct rb_node *parent = NULL;
        bool leftmost = true;

        while (*link != NULL) {
                parent = *link;
                if (less(node, parent)) {
                        link = &RB_LEFT(parent, __entry);
                } else {
                        link = &RB_RIGHT(parent, __entry);
                        leftmost = false;
                }
        }

        rb_link_node(node, parent, link);
        rb_insert_color_cached(node, tree, leftmost);

        return (leftmost ? node : NULL);
}

#undef RB_ROOT
#define RB_ROOT         (struct rb_root) { NULL }
#define RB_ROOT_CACHED  (struct rb_root_cached) { RB_ROOT, NULL }

#endif  /* _LINUXKPI_LINUX_RBTREE_H_ */