1 /* SPDX-License-Identifier: GPL-2.0+ */
2 /*
3 Red Black Trees
4 (C) 1999 Andrea Arcangeli <andrea@suse.de>
5
6 linux/include/linux/rbtree.h
7
8 To use rbtrees you'll have to implement your own insert and search cores.
9 This will avoid us to use callbacks and to drop drammatically performances.
10 I know it's not the cleaner way, but in C (not in C++) to get
11 performances and genericity...
12
13 See Documentation/rbtree.txt for documentation and samples.
14 */
15
16 #ifndef _LINUX_RBTREE_H
17 #define _LINUX_RBTREE_H
18
19 #ifndef __UBOOT__
20 #include <linux/kernel.h>
21 #endif
22 #include <linux/stddef.h>
23
24 struct rb_node {
25 unsigned long __rb_parent_color;
26 struct rb_node *rb_right;
27 struct rb_node *rb_left;
28 } __attribute__((aligned(sizeof(long))));
29 /* The alignment might seem pointless, but allegedly CRIS needs it */
30
31 struct rb_root {
32 struct rb_node *rb_node;
33 };
34
35 #define rb_parent(r) ((struct rb_node *)((r)->__rb_parent_color & ~3))
36
37 #define RB_ROOT (struct rb_root) { NULL, }
38 #define rb_entry(ptr, type, member) container_of(ptr, type, member)
39
40 #define RB_EMPTY_ROOT(root) ((root)->rb_node == NULL)
41
42 /* 'empty' nodes are nodes that are known not to be inserted in an rbree */
43 #define RB_EMPTY_NODE(node) \
44 ((node)->__rb_parent_color == (unsigned long)(node))
45 #define RB_CLEAR_NODE(node) \
46 ((node)->__rb_parent_color = (unsigned long)(node))
47
48 extern void rb_insert_color(struct rb_node *, struct rb_root *);
49 extern void rb_erase(struct rb_node *, struct rb_root *);
50
51 /* Find logical next and previous nodes in a tree */
52 extern struct rb_node *rb_next(const struct rb_node *);
53 extern struct rb_node *rb_prev(const struct rb_node *);
54 extern struct rb_node *rb_first(const struct rb_root *);
55 extern struct rb_node *rb_last(const struct rb_root *);
56
57 /* Postorder iteration - always visit the parent after its children */
58 extern struct rb_node *rb_first_postorder(const struct rb_root *);
59 extern struct rb_node *rb_next_postorder(const struct rb_node *);
60
61 /* Fast replacement of a single node without remove/rebalance/add/rebalance */
62 extern void rb_replace_node(struct rb_node *victim, struct rb_node *new,
63 struct rb_root *root);
64
rb_link_node(struct rb_node * node,struct rb_node * parent,struct rb_node ** rb_link)65 static inline void rb_link_node(struct rb_node * node, struct rb_node * parent,
66 struct rb_node ** rb_link)
67 {
68 node->__rb_parent_color = (unsigned long)parent;
69 node->rb_left = node->rb_right = NULL;
70
71 *rb_link = node;
72 }
73
74 #define rb_entry_safe(ptr, type, member) \
75 ({ typeof(ptr) ____ptr = (ptr); \
76 ____ptr ? rb_entry(____ptr, type, member) : NULL; \
77 })
78
79 /**
80 * rbtree_postorder_for_each_entry_safe - iterate over rb_root in post order of
81 * given type safe against removal of rb_node entry
82 *
83 * @pos: the 'type *' to use as a loop cursor.
84 * @n: another 'type *' to use as temporary storage
85 * @root: 'rb_root *' of the rbtree.
86 * @field: the name of the rb_node field within 'type'.
87 */
88 #define rbtree_postorder_for_each_entry_safe(pos, n, root, field) \
89 for (pos = rb_entry_safe(rb_first_postorder(root), typeof(*pos), field); \
90 pos && ({ n = rb_entry_safe(rb_next_postorder(&pos->field), \
91 typeof(*pos), field); 1; }); \
92 pos = n)
93
94 #endif /* _LINUX_RBTREE_H */
95