/*
  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...

  See Documentation/rbtree.txt for documentation and samples.
*/

#ifndef	_LINUX_RBTREE_H
#define	_LINUX_RBTREE_H

#include <linux/kernel.h>
#include <linux/stddef.h>

struct rb_node {
	unsigned long  __rb_parent_color;
	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_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)

/* 'empty' nodes are nodes that are known not to be inserted in an rbree */
#define RB_EMPTY_NODE(node)  \
	((node)->__rb_parent_color == (unsigned long)(node))
#define RB_CLEAR_NODE(node)  \
	((node)->__rb_parent_color = (unsigned long)(node))


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


struct rb_augment_callbacks {
	void (*propagate)(struct rb_node *node, struct rb_node *stop);
	void (*copy)(struct rb_node *old, struct rb_node *new);
	void (*rotate)(struct rb_node *old, struct rb_node *new);
};

extern void __rb_insert_augmented(struct rb_node *node, struct rb_root *root,
	void (*augment_rotate)(struct rb_node *old, struct rb_node *new));
extern void rb_erase_augmented(struct rb_node *node, struct rb_root *root,
			       const struct rb_augment_callbacks *augment);
static inline void
rb_insert_augmented(struct rb_node *node, struct rb_root *root,
		    const struct rb_augment_callbacks *augment)
{
	__rb_insert_augmented(node, root, augment->rotate);
}

#define RB_DECLARE_CALLBACKS(rbstatic, rbname, rbstruct, rbfield,	      \
			     rbtype, rbaugmented, rbcompute)		      \
static void rbname ## _propagate(struct rb_node *rb, struct rb_node *stop)    \
{									      \
	while (rb != stop) {						      \
		rbstruct *node = rb_entry(rb, rbstruct, rbfield);	      \
		rbtype augmented = rbcompute(node);			      \
		if (node->rbaugmented == augmented)			      \
			break;						      \
		node->rbaugmented = augmented;				      \
		rb = rb_parent(&node->rbfield);				      \
	}								      \
}									      \
static void rbname ## _copy(struct rb_node *rb_old, struct rb_node *rb_new)   \
{									      \
	rbstruct *old = rb_entry(rb_old, rbstruct, rbfield);		      \
	rbstruct *new = rb_entry(rb_new, rbstruct, rbfield);		      \
	new->rbaugmented = old->rbaugmented;				      \
}									      \
static void rbname ## _rotate(struct rb_node *rb_old, struct rb_node *rb_new) \
{									      \
	rbstruct *old = rb_entry(rb_old, rbstruct, rbfield);		      \
	rbstruct *new = rb_entry(rb_new, rbstruct, rbfield);		      \
	new->rbaugmented = old->rbaugmented;				      \
	old->rbaugmented = rbcompute(old);				      \
}									      \
rbstatic const struct rb_augment_callbacks rbname = {			      \
	rbname ## _propagate, rbname ## _copy, rbname ## _rotate	      \
};


/* 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, 
			    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 */