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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   See Documentation/rbtree.txt for documentation and samples.
27 */
28 
29 #ifndef __TOOLS_LINUX_PERF_RBTREE_H
30 #define __TOOLS_LINUX_PERF_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 rbtree */
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 #define rb_entry_safe(ptr, type, member) \
89 	({ typeof(ptr) ____ptr = (ptr); \
90 	   ____ptr ? rb_entry(____ptr, type, member) : NULL; \
91 	})
92 
93 
94 /*
95  * Handy for checking that we are not deleting an entry that is
96  * already in a list, found in block/{blk-throttle,cfq-iosched}.c,
97  * probably should be moved to lib/rbtree.c...
98  */
rb_erase_init(struct rb_node * n,struct rb_root * root)99 static inline void rb_erase_init(struct rb_node *n, struct rb_root *root)
100 {
101 	rb_erase(n, root);
102 	RB_CLEAR_NODE(n);
103 }
104 #endif /* __TOOLS_LINUX_PERF_RBTREE_H */
105