aboutsummaryrefslogtreecommitdiff
path: root/include/linux/rbtree.h
blob: 033b507b33b17075e5ab5cf287b264d3b9b22f35 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
/*
  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))

static inline void rb_init_node(struct rb_node *rb)
{
	rb->rb_parent_color = 0;
	rb->rb_right = NULL;
	rb->rb_left = NULL;
	RB_CLEAR_NODE(rb);
}

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 */