rbtree.h revision 7d82a4640abdcc3ffbd89c7971a11e4ac7953b7f 
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  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.
32
33-----------------------------------------------------------------------
34static 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
54static 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
80static 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/* ANDROID_CHANGE_BEGIN */
98#ifdef __APPLE__
99#include "../kernel.h"
100#else
101#include <linux/kernel.h>
102#include <linux/stddef.h>
103#endif
104/* ANDROID_CHANGE_END */
105
106struct rb_node
107{
108	unsigned long  rb_parent_color;
109#define	RB_RED		0
110#define	RB_BLACK	1
111	struct rb_node *rb_right;
112	struct rb_node *rb_left;
113} __attribute__((aligned(sizeof(long))));
114    /* The alignment might seem pointless, but allegedly CRIS needs it */
115
116struct rb_root
117{
118	struct rb_node *rb_node;
119};
120
121
122#define rb_parent(r)   ((struct rb_node *)((r)->rb_parent_color & ~3))
123#define rb_color(r)   ((r)->rb_parent_color & 1)
124#define rb_is_red(r)   (!rb_color(r))
125#define rb_is_black(r) rb_color(r)
126#define rb_set_red(r)  do { (r)->rb_parent_color &= ~1; } while (0)
127#define rb_set_black(r)  do { (r)->rb_parent_color |= 1; } while (0)
128
129static inline void rb_set_parent(struct rb_node *rb, struct rb_node *p)
130{
131	rb->rb_parent_color = (rb->rb_parent_color & 3) | (unsigned long)p;
132}
133static inline void rb_set_color(struct rb_node *rb, int color)
134{
135	rb->rb_parent_color = (rb->rb_parent_color & ~1) | color;
136}
137
138#define RB_ROOT	(struct rb_root) { NULL, }
139#define	rb_entry(ptr, type, member) container_of(ptr, type, member)
140
141#define RB_EMPTY_ROOT(root)	((root)->rb_node == NULL)
142#define RB_EMPTY_NODE(node)	(rb_parent(node) == node)
143#define RB_CLEAR_NODE(node)	(rb_set_parent(node, node))
144
145extern void rb_insert_color(struct rb_node *, struct rb_root *);
146extern void rb_erase(struct rb_node *, struct rb_root *);
147
148typedef void (*rb_augment_f)(struct rb_node *node, void *data);
149
150extern void rb_augment_insert(struct rb_node *node,
151			      rb_augment_f func, void *data);
152extern struct rb_node *rb_augment_erase_begin(struct rb_node *node);
153extern void rb_augment_erase_end(struct rb_node *node,
154				 rb_augment_f func, void *data);
155
156/* Find logical next and previous nodes in a tree */
157extern struct rb_node *rb_next(const struct rb_node *);
158extern struct rb_node *rb_prev(const struct rb_node *);
159extern struct rb_node *rb_first(const struct rb_root *);
160extern struct rb_node *rb_last(const struct rb_root *);
161
162/* Fast replacement of a single node without remove/rebalance/add/rebalance */
163extern void rb_replace_node(struct rb_node *victim, struct rb_node *new,
164			    struct rb_root *root);
165
166static inline void rb_link_node(struct rb_node * node, struct rb_node * parent,
167				struct rb_node ** rb_link)
168{
169	node->rb_parent_color = (unsigned long )parent;
170	node->rb_left = node->rb_right = NULL;
171
172	*rb_link = node;
173}
174
175#endif	/* _LINUX_RBTREE_H */
176