source: svn/trunk/newcon3bcm2_21bu/toolchain/mipsel-linux-uclibc/include/linux/rbtree.h @ 52

Last change on this file since 52 was 2, checked in by jglee, 11 years ago

first commit
  • Property svn:executable set to *
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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-----------------------------------------------------------------------
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#include <linux/kernel.h>
98#include <linux/stddef.h>
99
100struct rb_node
101{
102        struct rb_node *rb_parent;
103        int rb_color;
104#define RB_RED          0
105#define RB_BLACK        1
106        struct rb_node *rb_right;
107        struct rb_node *rb_left;
108};
109
110struct rb_root
111{
112        struct rb_node *rb_node;
113};
114
115#define RB_ROOT (struct rb_root) { NULL, }
116#define rb_entry(ptr, type, member) container_of(ptr, type, member)
117
118extern void rb_insert_color(struct rb_node *, struct rb_root *);
119extern void rb_erase(struct rb_node *, struct rb_root *);
120
121/* Find logical next and previous nodes in a tree */
122extern struct rb_node *rb_next(struct rb_node *);
123extern struct rb_node *rb_prev(struct rb_node *);
124extern struct rb_node *rb_first(struct rb_root *);
125extern struct rb_node *rb_last(struct rb_root *);
126
127/* Fast replacement of a single node without remove/rebalance/add/rebalance */
128extern void rb_replace_node(struct rb_node *victim, struct rb_node *new, 
129                            struct rb_root *root);
130
131static inline void rb_link_node(struct rb_node * node, struct rb_node * parent,
132                                struct rb_node ** rb_link)
133{
134        node->rb_parent = parent;
135        node->rb_color = RB_RED;
136        node->rb_left = node->rb_right = NULL;
137
138        *rb_link = node;
139}
140
141#endif  /* _LINUX_RBTREE_H */
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