[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>

struct rb_node
{
	struct rb_node *rb_parent;
	int rb_color;
#define	RB_RED		0
#define	RB_BLACK	1
	struct rb_node *rb_right;
	struct rb_node *rb_left;
};

struct rb_root
{
	struct rb_node *rb_node;
};

#undef offsetof
#ifdef __compiler_offsetof
#define offsetof(TYPE,MEMBER) __compiler_offsetof(TYPE,MEMBER)
#else
#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
#endif

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

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

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(struct rb_node *);
extern struct rb_node *rb_prev(struct rb_node *);
extern struct rb_node *rb_first(struct rb_root *);
extern struct rb_node *rb_last(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 = parent;
	node->rb_color = RB_RED;
	node->rb_left = node->rb_right = NULL;

	*rb_link = node;
}

#endif	/* _LINUX_RBTREE_H */
Commit	Line	Data
4b87898e JA	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
99	struct rb_node
100	{
101	struct rb_node *rb_parent;
102	int rb_color;
103	#define RB_RED 0
104	#define RB_BLACK 1
105	struct rb_node *rb_right;
106	struct rb_node *rb_left;
107	};
108
109	struct rb_root
110	{
111	struct rb_node *rb_node;
112	};
113
114	#undef offsetof
115	#ifdef __compiler_offsetof
116	#define offsetof(TYPE,MEMBER) __compiler_offsetof(TYPE,MEMBER)
117	#else
118	#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
119	#endif
120
121	#define container_of(ptr, type, member) ({ \
122	const typeof( ((type )0)->member ) __mptr = (ptr); \
123	(type )( (char )__mptr - offsetof(type,member) );})
124
125	#define RB_ROOT (struct rb_root) { NULL, }
126	#define rb_entry(ptr, type, member) container_of(ptr, type, member)
127
128	extern void rb_insert_color(struct rb_node , struct rb_root );
129	extern void rb_erase(struct rb_node , struct rb_root );
130
131	/* Find logical next and previous nodes in a tree */
132	extern struct rb_node rb_next(struct rb_node );
133	extern struct rb_node rb_prev(struct rb_node );
134	extern struct rb_node rb_first(struct rb_root );
135	extern struct rb_node rb_last(struct rb_root );
136
137	static inline void rb_link_node(struct rb_node * node, struct rb_node * parent,
138	struct rb_node ** rb_link)
139	{
140	node->rb_parent = parent;
141	node->rb_color = RB_RED;
142	node->rb_left = node->rb_right = NULL;
143
144	*rb_link = node;
145	}
146
147	#endif /* _LINUX_RBTREE_H */