/*
  Red Black Trees
  (C) 1999  Andrea Arcangeli <andrea@suse.de>
  
  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 2 of the License, or
  (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

  linux/lib/rbtree.c
*/

#include <linux/rbtree.h>
#include <linux/module.h>

static void __rb_rotate_left(rb_node_t * node, rb_root_t * root)
{
        rb_node_t * right = node->rb_right;

        if ((node->rb_right = right->rb_left))
                right->rb_left->rb_parent = node;
        right->rb_left = node;

        if ((right->rb_parent = node->rb_parent))
        {
                if (node == node->rb_parent->rb_left)
                        node->rb_parent->rb_left = right;
                else
                        node->rb_parent->rb_right = right;
        }
        else
                root->rb_node = right;
        node->rb_parent = right;
}

static void __rb_rotate_right(rb_node_t * node, rb_root_t * root)
{
        rb_node_t * left = node->rb_left;

        if ((node->rb_left = left->rb_right))
                left->rb_right->rb_parent = node;
        left->rb_right = node;

        if ((left->rb_parent = node->rb_parent))
        {
                if (node == node->rb_parent->rb_right)
                        node->rb_parent->rb_right = left;
                else
                        node->rb_parent->rb_left = left;
        }
        else
                root->rb_node = left;
        node->rb_parent = left;
}

void rb_insert_color(rb_node_t * node, rb_root_t * root)
{
        rb_node_t * parent, * gparent;

        while ((parent = node->rb_parent) && parent->rb_color == RB_RED)
        {
                gparent = parent->rb_parent;

                if (parent == gparent->rb_left)
                {
                        {
                                register rb_node_t * uncle = gparent->rb_right;
                                if (uncle && uncle->rb_color == RB_RED)
                                {
                                        uncle->rb_color = RB_BLACK;
                                        parent->rb_color = RB_BLACK;
                                        gparent->rb_color = RB_RED;
                                        node = gparent;
                                        continue;
                                }
                        }

                        if (parent->rb_right == node)
                        {
                                register rb_node_t * tmp;
                                __rb_rotate_left(parent, root);
                                tmp = parent;
                                parent = node;
                                node = tmp;
                        }

                        parent->rb_color = RB_BLACK;
                        gparent->rb_color = RB_RED;
                        __rb_rotate_right(gparent, root);
                } else {
                        {
                                register rb_node_t * uncle = gparent->rb_left;
                                if (uncle && uncle->rb_color == RB_RED)
                                {
                                        uncle->rb_color = RB_BLACK;
                                        parent->rb_color = RB_BLACK;
                                        gparent->rb_color = RB_RED;
                                        node = gparent;
                                        continue;
                                }
                        }

                        if (parent->rb_left == node)
                        {
                                register rb_node_t * tmp;
                                __rb_rotate_right(parent, root);
                                tmp = parent;
                                parent = node;
                                node = tmp;
                        }

                        parent->rb_color = RB_BLACK;
                        gparent->rb_color = RB_RED;
                        __rb_rotate_left(gparent, root);
                }
        }

        root->rb_node->rb_color = RB_BLACK;
}
EXPORT_SYMBOL(rb_insert_color);

static void __rb_erase_color(rb_node_t * node, rb_node_t * parent,
                             rb_root_t * root)
{
        rb_node_t * other;

        while ((!node || node->rb_color == RB_BLACK) && node != root->rb_node)
        {
                if (parent->rb_left == node)
                {
                        other = parent->rb_right;
                        if (other->rb_color == RB_RED)
                        {
                                other->rb_color = RB_BLACK;
                                parent->rb_color = RB_RED;
                                __rb_rotate_left(parent, root);
                                other = parent->rb_right;
                        }
                        if ((!other->rb_left ||
                             other->rb_left->rb_color == RB_BLACK)
                            && (!other->rb_right ||
                                other->rb_right->rb_color == RB_BLACK))
                        {
                                other->rb_color = RB_RED;
                                node = parent;
                                parent = node->rb_parent;
                        }
                        else
                        {
                                if (!other->rb_right ||
                                    other->rb_right->rb_color == RB_BLACK)
                                {
                                        register rb_node_t * o_left;
                                        if ((o_left = other->rb_left))
                                                o_left->rb_color = RB_BLACK;
                                        other->rb_color = RB_RED;
                                        __rb_rotate_right(other, root);
                                        other = parent->rb_right;
                                }
                                other->rb_color = parent->rb_color;
                                parent->rb_color = RB_BLACK;
                                if (other->rb_right)
                                        other->rb_right->rb_color = RB_BLACK;
                                __rb_rotate_left(parent, root);
                                node = root->rb_node;
                                break;
                        }
                }
                else
                {
                        other = parent->rb_left;
                        if (other->rb_color == RB_RED)
                        {
                                other->rb_color = RB_BLACK;
                                parent->rb_color = RB_RED;
                                __rb_rotate_right(parent, root);
                                other = parent->rb_left;
                        }
                        if ((!other->rb_left ||
                             other->rb_left->rb_color == RB_BLACK)
                            && (!other->rb_right ||
                                other->rb_right->rb_color == RB_BLACK))
                        {
                                other->rb_color = RB_RED;
                                node = parent;
                                parent = node->rb_parent;
                        }
                        else
                        {
                                if (!other->rb_left ||
                                    other->rb_left->rb_color == RB_BLACK)
                                {
                                        register rb_node_t * o_right;
                                        if ((o_right = other->rb_right))
                                                o_right->rb_color = RB_BLACK;
                                        other->rb_color = RB_RED;
                                        __rb_rotate_left(other, root);
                                        other = parent->rb_left;
                                }
                                other->rb_color = parent->rb_color;
                                parent->rb_color = RB_BLACK;
                                if (other->rb_left)
                                        other->rb_left->rb_color = RB_BLACK;
                                __rb_rotate_right(parent, root);
                                node = root->rb_node;
                                break;
                        }
                }
        }
        if (node)
                node->rb_color = RB_BLACK;
}

void rb_erase(rb_node_t * node, rb_root_t * root)
{
        rb_node_t * child, * parent;
        int color;

        if (!node->rb_left)
                child = node->rb_right;
        else if (!node->rb_right)
                child = node->rb_left;
        else
        {
                rb_node_t * old = node, * left;

                node = node->rb_right;
                while ((left = node->rb_left))
                        node = left;
                child = node->rb_right;
                parent = node->rb_parent;
                color = node->rb_color;

                if (child)
                        child->rb_parent = parent;
                if (parent)
                {
                        if (parent->rb_left == node)
                                parent->rb_left = child;
                        else
                                parent->rb_right = child;
                }
                else
                        root->rb_node = child;

                if (node->rb_parent == old)
                        parent = node;
                node->rb_parent = old->rb_parent;
                node->rb_color = old->rb_color;
                node->rb_right = old->rb_right;
                node->rb_left = old->rb_left;

                if (old->rb_parent)
                {
                        if (old->rb_parent->rb_left == old)
                                old->rb_parent->rb_left = node;
                        else
                                old->rb_parent->rb_right = node;
                } else
                        root->rb_node = node;

                old->rb_left->rb_parent = node;
                if (old->rb_right)
                        old->rb_right->rb_parent = node;
                goto color;
        }

        parent = node->rb_parent;
        color = node->rb_color;

        if (child)
                child->rb_parent = parent;
        if (parent)
        {
                if (parent->rb_left == node)
                        parent->rb_left = child;
                else
                        parent->rb_right = child;
        }
        else
                root->rb_node = child;

 color:
        if (color == RB_BLACK)
                __rb_erase_color(child, parent, root);
}
EXPORT_SYMBOL(rb_erase);