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rbtree.h
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1 /*
2  Red Black Trees
3  (C) 1999 Andrea Arcangeli <[email protected]>
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  See Documentation/rbtree.txt for documentation and samples.
27 */
28 
29 #ifndef _LINUX_RBTREE_H
30 #define _LINUX_RBTREE_H
31 
32 #include <linux/kernel.h>
33 #include <linux/stddef.h>
34 
35 struct rb_node {
36  unsigned long __rb_parent_color;
37  struct rb_node *rb_right;
38  struct rb_node *rb_left;
39 } __attribute__((aligned(sizeof(long))));
40  /* The alignment might seem pointless, but allegedly CRIS needs it */
41 
42 struct rb_root {
43  struct rb_node *rb_node;
44 };
45 
46 
47 #define rb_parent(r) ((struct rb_node *)((r)->__rb_parent_color & ~3))
48 
49 #define RB_ROOT (struct rb_root) { NULL, }
50 #define rb_entry(ptr, type, member) container_of(ptr, type, member)
51 
52 #define RB_EMPTY_ROOT(root) ((root)->rb_node == NULL)
53 
54 /* 'empty' nodes are nodes that are known not to be inserted in an rbree */
55 #define RB_EMPTY_NODE(node) \
56  ((node)->__rb_parent_color == (unsigned long)(node))
57 #define RB_CLEAR_NODE(node) \
58  ((node)->__rb_parent_color = (unsigned long)(node))
59 
60 
61 extern void rb_insert_color(struct rb_node *, struct rb_root *);
62 extern void rb_erase(struct rb_node *, struct rb_root *);
63 
64 
65 /* Find logical next and previous nodes in a tree */
66 extern struct rb_node *rb_next(const struct rb_node *);
67 extern struct rb_node *rb_prev(const struct rb_node *);
68 extern struct rb_node *rb_first(const struct rb_root *);
69 extern struct rb_node *rb_last(const struct rb_root *);
70 
71 /* Fast replacement of a single node without remove/rebalance/add/rebalance */
72 extern void rb_replace_node(struct rb_node *victim, struct rb_node *new,
73  struct rb_root *root);
74 
75 static inline void rb_link_node(struct rb_node * node, struct rb_node * parent,
76  struct rb_node ** rb_link)
77 {
78  node->__rb_parent_color = (unsigned long)parent;
79  node->rb_left = node->rb_right = NULL;
80 
81  *rb_link = node;
82 }
83 
84 #endif /* _LINUX_RBTREE_H */