/*
  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/include/linux/rbtree.h

  To use rbtrees you'll have to implement your own insert and search cores.
  This will avoid us to use callbacks and to drop drammatically performances.
  I know it's not the cleaner way,  but in C (not in C++) to get
  performances and genericity...
*/

#ifndef _LINUX_RBTREE_H
#define _LINUX_RBTREE_H

#include <stddef.h> /* NULL */

#ifndef container_of
#define container_of(ptr, type, member)                                                            \
	({                                                                                         \
		const typeof(((type *)0)->member) *__mptr = (ptr);                                 \
		(type *)((char *)__mptr - offsetof(type, member));                                 \
	})
#endif

struct rb_node {
	unsigned long rb_parent_color;
#define RB_RED 0
#define RB_BLACK 1
	struct rb_node *rb_right;
	struct rb_node *rb_left;
} __attribute__((aligned(sizeof(long))));
/* The alignment might seem pointless, but allegedly CRIS needs it */

struct rb_root {
	struct rb_node *rb_node;
};

#define rb_parent(r) ((struct rb_node *)((r)->rb_parent_color & ~3))
#define rb_color(r) ((r)->rb_parent_color & 1)
#define rb_is_red(r) (!rb_color(r))
#define rb_is_black(r) rb_color(r)
#define rb_set_red(r)                                                                              \
	do {                                                                                       \
		(r)->rb_parent_color &= ~1;                                                        \
	} while (0)
#define rb_set_black(r)                                                                            \
	do {                                                                                       \
		(r)->rb_parent_color |= 1;                                                         \
	} while (0)

static inline void rb_set_parent(struct rb_node *rb, struct rb_node *p)
{
	rb->rb_parent_color = (rb->rb_parent_color & 3) | (unsigned long)p;
}
static inline void rb_set_color(struct rb_node *rb, int color)
{
	rb->rb_parent_color = (rb->rb_parent_color & ~1) | color;
}

#define RB_ROOT                                                                                    \
	(struct rb_root)                                                                           \
	{                                                                                          \
		NULL,                                                                              \
	}
#define rb_entry(ptr, type, member) container_of(ptr, type, member)

#define RB_EMPTY_ROOT(root) ((root)->rb_node == NULL)
#define RB_EMPTY_NODE(node) (rb_parent(node) == node)
#define RB_CLEAR_NODE(node) (rb_set_parent(node, node))

extern void rb_insert_color(struct rb_node *, struct rb_root *);
extern void rb_erase(struct rb_node *, struct rb_root *);

/* Find logical next and previous nodes in a tree */
extern struct rb_node *rb_next(const struct rb_node *);
extern struct rb_node *rb_prev(const struct rb_node *);
extern struct rb_node *rb_first(const struct rb_root *);
extern struct rb_node *rb_last(const struct rb_root *);

/* Fast replacement of a single node without remove/rebalance/add/rebalance */
extern void rb_replace_node(struct rb_node *victim, struct rb_node *new_entry,
			    struct rb_root *root);

static inline void rb_link_node(struct rb_node *node, struct rb_node *parent,
				struct rb_node **rb_link)
{
	node->rb_parent_color = (unsigned long)parent;
	node->rb_left = node->rb_right = NULL;

	*rb_link = node;
}

#endif /* _LINUX_RBTREE_H */
