[fio.git] / 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
  int two steps: as first thing the code must insert the element in
  order as a red leaf in the tree, 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 <stdlib.h>
#include <inttypes.h>

struct rb_node
{
	intptr_t 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) | (uintptr_t)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_first(struct rb_root *);

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

	*rb_link = node;
}

#endif	/* _LINUX_RBTREE_H */
Commit	Line	Data
	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
	28	int two steps: as first thing the code must insert the element in
	29	order as a red leaf in the tree, then the support library function
	30	rb_insert_color() must be called. Such function will do the
	31	not trivial work to rebalance the rbtree if necessary.
	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 <stdlib.h>
	98	#include <inttypes.h>
	99
	100	struct rb_node
	101	{
	102	intptr_t rb_parent_color;
	103	#define RB_RED 0
	104	#define RB_BLACK 1
	105	struct rb_node *rb_right;
	106	struct rb_node *rb_left;
	107	} __attribute__((aligned(sizeof(long))));
	108	/* The alignment might seem pointless, but allegedly CRIS needs it */
	109
	110	struct rb_root
	111	{
	112	struct rb_node *rb_node;
	113	};
	114
	115
	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)
	122
	123	static inline void rb_set_parent(struct rb_node rb, struct rb_node p)
	124	{
	125	rb->rb_parent_color = (rb->rb_parent_color & 3) \| (uintptr_t)p;
	126	}
	127	static inline void rb_set_color(struct rb_node *rb, int color)
	128	{
	129	rb->rb_parent_color = (rb->rb_parent_color & ~1) \| color;
	130	}
	131
	132	#define RB_ROOT (struct rb_root) { NULL, }
	133	#define rb_entry(ptr, type, member) container_of(ptr, type, member)
	134
	135	#define RB_EMPTY_ROOT(root) ((root)->rb_node == NULL)
	136	#define RB_EMPTY_NODE(node) (rb_parent(node) == node)
	137	#define RB_CLEAR_NODE(node) (rb_set_parent(node, node))
	138
	139	extern void rb_insert_color(struct rb_node , struct rb_root );
	140	extern void rb_erase(struct rb_node , struct rb_root );
	141
	142	/* Find logical next and previous nodes in a tree */
	143	extern struct rb_node rb_first(struct rb_root );
	144
	145	static inline void rb_link_node(struct rb_node * node, struct rb_node * parent,
	146	struct rb_node ** rb_link)
	147	{
	148	node->rb_parent_color = (uintptr_t)parent;
	149	node->rb_left = node->rb_right = NULL;
	150
	151	*rb_link = node;
	152	}
	153
	154	#endif /* _LINUX_RBTREE_H */