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 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 /* Postorder iteration - always visit the parent after its children */
72 extern struct rb_node *rb_first_postorder(const struct rb_root *);
73 extern struct rb_node *rb_next_postorder(const struct rb_node *);
74
75 /* Fast replacement of a single node without remove/rebalance/add/rebalance */
76 extern void rb_replace_node(struct rb_node *victim, struct rb_node *new,
77 struct rb_root *root);
78
rb_link_node(struct rb_node * node,struct rb_node * parent,struct rb_node ** rb_link)79 static inline void rb_link_node(struct rb_node * node, struct rb_node * parent,
80 struct rb_node ** rb_link)
81 {
82 node->__rb_parent_color = (unsigned long)parent;
83 node->rb_left = node->rb_right = NULL;
84
85 *rb_link = node;
86 }
87
88 /**
89 * rbtree_postorder_for_each_entry_safe - iterate over rb_root in post order of
90 * given type safe against removal of rb_node entry
91 *
92 * @pos: the 'type *' to use as a loop cursor.
93 * @n: another 'type *' to use as temporary storage
94 * @root: 'rb_root *' of the rbtree.
95 * @field: the name of the rb_node field within 'type'.
96 */
97 #define rbtree_postorder_for_each_entry_safe(pos, n, root, field) \
98 for (pos = rb_entry(rb_first_postorder(root), typeof(*pos), field),\
99 n = rb_entry(rb_next_postorder(&pos->field), \
100 typeof(*pos), field); \
101 &pos->field; \
102 pos = n, \
103 n = rb_entry(rb_next_postorder(&pos->field), \
104 typeof(*pos), field))
105
106 #endif /* _LINUX_RBTREE_H */
107