[net-next-2.6.git] / include / linux / rbtree.h

/*
  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...

  Some example of insert and search follows here. The search is a plain
  normal search over an ordered tree. The insert instead must be implemented
  in two steps: First, the code must insert the element in order as a red leaf
  in the tree, and then the support library function rb_insert_color() must
  be called. Such function will do the not trivial work to rebalance the
  rbtree, if necessary.

-----------------------------------------------------------------------
static inline struct page * rb_search_page_cache(struct inode * inode,
						 unsigned long offset)
{
	struct rb_node * n = inode->i_rb_page_cache.rb_node;
	struct page * page;

	while (n)
	{
		page = rb_entry(n, struct page, rb_page_cache);

		if (offset < page->offset)
			n = n->rb_left;
		else if (offset > page->offset)
			n = n->rb_right;
		else
			return page;
	}
	return NULL;
}

static inline struct page * __rb_insert_page_cache(struct inode * inode,
						   unsigned long offset,
						   struct rb_node * node)
{
	struct rb_node ** p = &inode->i_rb_page_cache.rb_node;
	struct rb_node * parent = NULL;
	struct page * page;

	while (*p)
	{
		parent = *p;
		page = rb_entry(parent, struct page, rb_page_cache);

		if (offset < page->offset)
			p = &(*p)->rb_left;
		else if (offset > page->offset)
			p = &(*p)->rb_right;
		else
			return page;
	}

	rb_link_node(node, parent, p);

	return NULL;
}

static inline struct page * rb_insert_page_cache(struct inode * inode,
						 unsigned long offset,
						 struct rb_node * node)
{
	struct page * ret;
	if ((ret = __rb_insert_page_cache(inode, offset, node)))
		goto out;
	rb_insert_color(node, &inode->i_rb_page_cache);
 out:
	return ret;
}
-----------------------------------------------------------------------
*/

#ifndef	_LINUX_RBTREE_H
#define	_LINUX_RBTREE_H

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

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 *);

typedef void (*rb_augment_f)(struct rb_node *node, void *data);

extern void rb_augment_insert(struct rb_node *node,
			      rb_augment_f func, void *data);
extern struct rb_node *rb_augment_erase_begin(struct rb_node *node);
extern void rb_augment_erase_end(struct rb_node *node,
				 rb_augment_f func, void *data);

/* 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 */
Commit	Line	Data
1da177e4 LT	1	/*
	2	Red Black Trees
	3	(C) 1999 Andrea Arcangeli <andrea@suse.de>
	4
	5	This program is free software; you can redistribute it and/or modify
	6	it under the terms of the GNU General Public License as published by
	7	the Free Software Foundation; either version 2 of the License, or
	8	(at your option) any later version.
	9
	10	This program is distributed in the hope that it will be useful,
	11	but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	13	GNU General Public License for more details.
	14
	15	You should have received a copy of the GNU General Public License
	16	along with this program; if not, write to the Free Software
	17	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	18
	19	linux/include/linux/rbtree.h
	20
	21	To use rbtrees you'll have to implement your own insert and search cores.
	22	This will avoid us to use callbacks and to drop drammatically performances.
	23	I know it's not the cleaner way, but in C (not in C++) to get
	24	performances and genericity...
	25
	26	Some example of insert and search follows here. The search is a plain
	27	normal search over an ordered tree. The insert instead must be implemented
3e589740 NK	28	in two steps: First, the code must insert the element in order as a red leaf
	29	in the tree, and then the support library function rb_insert_color() must
	30	be called. Such function will do the not trivial work to rebalance the
	31	rbtree, if necessary.
1da177e4 LT	32
	33	-----------------------------------------------------------------------
	34	static inline struct page * rb_search_page_cache(struct inode * inode,
	35	unsigned long offset)
	36	{
	37	struct rb_node * n = inode->i_rb_page_cache.rb_node;
	38	struct page * page;
	39
	40	while (n)
	41	{
	42	page = rb_entry(n, struct page, rb_page_cache);
	43
	44	if (offset < page->offset)
	45	n = n->rb_left;
	46	else if (offset > page->offset)
	47	n = n->rb_right;
	48	else
	49	return page;
	50	}
	51	return NULL;
	52	}
	53
	54	static inline struct page * __rb_insert_page_cache(struct inode * inode,
	55	unsigned long offset,
	56	struct rb_node * node)
	57	{
	58	struct rb_node ** p = &inode->i_rb_page_cache.rb_node;
	59	struct rb_node * parent = NULL;
	60	struct page * page;
	61
	62	while (*p)
	63	{
	64	parent = *p;
	65	page = rb_entry(parent, struct page, rb_page_cache);
	66
	67	if (offset < page->offset)
	68	p = &(*p)->rb_left;
	69	else if (offset > page->offset)
	70	p = &(*p)->rb_right;
	71	else
	72	return page;
	73	}
	74
	75	rb_link_node(node, parent, p);
	76
	77	return NULL;
	78	}
	79
	80	static inline struct page * rb_insert_page_cache(struct inode * inode,
	81	unsigned long offset,
	82	struct rb_node * node)
	83	{
	84	struct page * ret;
	85	if ((ret = __rb_insert_page_cache(inode, offset, node)))
	86	goto out;
	87	rb_insert_color(node, &inode->i_rb_page_cache);
	88	out:
	89	return ret;
	90	}
	91	-----------------------------------------------------------------------
	92	*/
	93
	94	#ifndef _LINUX_RBTREE_H
	95	#define _LINUX_RBTREE_H
96
97	#include <linux/kernel.h>
98	#include <linux/stddef.h>
99
100	struct rb_node
101	{
2f3243ae	102	unsigned long rb_parent_color;
1da177e4 LT	103	#define RB_RED 0
	104	#define RB_BLACK 1
	105	struct rb_node *rb_right;
	106	struct rb_node *rb_left;
e977145a DW	107	} __attribute__((aligned(sizeof(long))));
e977145a DW	108	/* The alignment might seem pointless, but allegedly CRIS needs it */
1da177e4 LT	109
	110	struct rb_root
	111	{
	112	struct rb_node *rb_node;
	113	};
	114
55a98102	115
2f3243ae DW	116	#define rb_parent(r) ((struct rb_node *)((r)->rb_parent_color & ~3))
	117	#define rb_color(r) ((r)->rb_parent_color & 1)
	118	#define rb_is_red(r) (!rb_color(r))
	119	#define rb_is_black(r) rb_color(r)
	120	#define rb_set_red(r) do { (r)->rb_parent_color &= ~1; } while (0)
	121	#define rb_set_black(r) do { (r)->rb_parent_color \|= 1; } while (0)
55a98102 DW	122
	123	static inline void rb_set_parent(struct rb_node rb, struct rb_node p)
	124	{
2f3243ae	125	rb->rb_parent_color = (rb->rb_parent_color & 3) \| (unsigned long)p;
55a98102	126	}
2f3243ae	127	static inline void rb_set_color(struct rb_node *rb, int color)
55a98102	128	{
2f3243ae	129	rb->rb_parent_color = (rb->rb_parent_color & ~1) \| color;
55a98102 DW	130	}
55a98102 DW	131
b945d6b2	132	#define RB_ROOT (struct rb_root) { NULL, }
1da177e4 LT	133	#define rb_entry(ptr, type, member) container_of(ptr, type, member)
1da177e4 LT	134
dd67d051	135	#define RB_EMPTY_ROOT(root) ((root)->rb_node == NULL)
10fd48f2	136	#define RB_EMPTY_NODE(node) (rb_parent(node) == node)
dd67d051 JA	137	#define RB_CLEAR_NODE(node) (rb_set_parent(node, node))
dd67d051 JA	138
1da177e4 LT	139	extern void rb_insert_color(struct rb_node , struct rb_root );
	140	extern void rb_erase(struct rb_node , struct rb_root );
	141
b945d6b2 PZ	142	typedef void (rb_augment_f)(struct rb_node node, void *data);
	143
	144	extern void rb_augment_insert(struct rb_node *node,
	145	rb_augment_f func, void *data);
	146	extern struct rb_node rb_augment_erase_begin(struct rb_node node);
	147	extern void rb_augment_erase_end(struct rb_node *node,
	148	rb_augment_f func, void *data);
	149
1da177e4	150	/* Find logical next and previous nodes in a tree */
f4b477c4 AB	151	extern struct rb_node rb_next(const struct rb_node );
	152	extern struct rb_node rb_prev(const struct rb_node );
	153	extern struct rb_node rb_first(const struct rb_root );
	154	extern struct rb_node rb_last(const struct rb_root );
1da177e4 LT	155
	156	/* Fast replacement of a single node without remove/rebalance/add/rebalance */
	157	extern void rb_replace_node(struct rb_node victim, struct rb_node new,
	158	struct rb_root *root);
	159
	160	static inline void rb_link_node(struct rb_node * node, struct rb_node * parent,
	161	struct rb_node ** rb_link)
	162	{
2f3243ae	163	node->rb_parent_color = (unsigned long )parent;
1da177e4 LT	164	node->rb_left = node->rb_right = NULL;
	165
	166	*rb_link = node;
	167	}
	168
	169	#endif /* _LINUX_RBTREE_H */