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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
35struct 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
42struct rb_root {
43 struct rb_node *rb_node;
44};
45
46/*
47 * Leftmost-cached rbtrees.
48 *
49 * We do not cache the rightmost node based on footprint
50 * size vs number of potential users that could benefit
51 * from O(1) rb_last(). Just not worth it, users that want
52 * this feature can always implement the logic explicitly.
53 * Furthermore, users that want to cache both pointers may
54 * find it a bit asymmetric, but that's ok.
55 */
56struct rb_root_cached {
57 struct rb_root rb_root;
58 struct rb_node *rb_leftmost;
59};
60
61#define rb_parent(r) ((struct rb_node *)((r)->__rb_parent_color & ~3))
62
63#define RB_ROOT (struct rb_root) { NULL, }
64#define RB_ROOT_CACHED (struct rb_root_cached) { {NULL, }, NULL }
65#define rb_entry(ptr, type, member) container_of(ptr, type, member)
66
67#define RB_EMPTY_ROOT(root) (READ_ONCE((root)->rb_node) == NULL)
68
69/* 'empty' nodes are nodes that are known not to be inserted in an rbtree */
70#define RB_EMPTY_NODE(node) \
71 ((node)->__rb_parent_color == (unsigned long)(node))
72#define RB_CLEAR_NODE(node) \
73 ((node)->__rb_parent_color = (unsigned long)(node))
74
75
76extern void rb_insert_color(struct rb_node *, struct rb_root *);
77extern void rb_erase(struct rb_node *, struct rb_root *);
78
79
80/* Find logical next and previous nodes in a tree */
81extern struct rb_node *rb_next(const struct rb_node *);
82extern struct rb_node *rb_prev(const struct rb_node *);
83extern struct rb_node *rb_first(const struct rb_root *);
84extern struct rb_node *rb_last(const struct rb_root *);
85
86extern void rb_insert_color_cached(struct rb_node *,
87 struct rb_root_cached *, bool);
88extern void rb_erase_cached(struct rb_node *node, struct rb_root_cached *);
89/* Same as rb_first(), but O(1) */
90#define rb_first_cached(root) (root)->rb_leftmost
91
92/* Postorder iteration - always visit the parent after its children */
93extern struct rb_node *rb_first_postorder(const struct rb_root *);
94extern struct rb_node *rb_next_postorder(const struct rb_node *);
95
96/* Fast replacement of a single node without remove/rebalance/add/rebalance */
97extern void rb_replace_node(struct rb_node *victim, struct rb_node *new,
98 struct rb_root *root);
99extern void rb_replace_node_cached(struct rb_node *victim, struct rb_node *new,
100 struct rb_root_cached *root);
101
102static inline void rb_link_node(struct rb_node *node, struct rb_node *parent,
103 struct rb_node **rb_link)
104{
105 node->__rb_parent_color = (unsigned long)parent;
106 node->rb_left = node->rb_right = NULL;
107
108 *rb_link = node;
109}
110
111#define rb_entry_safe(ptr, type, member) \
112 ({ typeof(ptr) ____ptr = (ptr); \
113 ____ptr ? rb_entry(____ptr, type, member) : NULL; \
114 })
115
116/**
117 * rbtree_postorder_for_each_entry_safe - iterate in post-order over rb_root of
118 * given type allowing the backing memory of @pos to be invalidated
119 *
120 * @pos: the 'type *' to use as a loop cursor.
121 * @n: another 'type *' to use as temporary storage
122 * @root: 'rb_root *' of the rbtree.
123 * @field: the name of the rb_node field within 'type'.
124 *
125 * rbtree_postorder_for_each_entry_safe() provides a similar guarantee as
126 * list_for_each_entry_safe() and allows the iteration to continue independent
127 * of changes to @pos by the body of the loop.
128 *
129 * Note, however, that it cannot handle other modifications that re-order the
130 * rbtree it is iterating over. This includes calling rb_erase() on @pos, as
131 * rb_erase() may rebalance the tree, causing us to miss some nodes.
132 */
133#define rbtree_postorder_for_each_entry_safe(pos, n, root, field) \
134 for (pos = rb_entry_safe(rb_first_postorder(root), typeof(*pos), field); \
135 pos && ({ n = rb_entry_safe(rb_next_postorder(&pos->field), \
136 typeof(*pos), field); 1; }); \
137 pos = n)
138
139static inline void rb_erase_init(struct rb_node *n, struct rb_root *root)
140{
141 rb_erase(n, root);
142 RB_CLEAR_NODE(n);
143}
144#endif /* __TOOLS_LINUX_PERF_RBTREE_H */