xref: /openbmc/u-boot/include/linux/rbtree.h (revision ebce73f0)
1 /*
2   Red Black Trees
3   (C) 1999  Andrea Arcangeli <andrea@suse.de>
4 
5  * SPDX-License-Identifier:	GPL-2.0+
6 
7   linux/include/linux/rbtree.h
8 
9   To use rbtrees you'll have to implement your own insert and search cores.
10   This will avoid us to use callbacks and to drop drammatically performances.
11   I know it's not the cleaner way,  but in C (not in C++) to get
12   performances and genericity...
13 
14   See Documentation/rbtree.txt for documentation and samples.
15 */
16 
17 #ifndef	_LINUX_RBTREE_H
18 #define	_LINUX_RBTREE_H
19 
20 #ifndef __UBOOT__
21 #include <linux/kernel.h>
22 #endif
23 #include <linux/stddef.h>
24 
25 struct rb_node {
26 	unsigned long  __rb_parent_color;
27 	struct rb_node *rb_right;
28 	struct rb_node *rb_left;
29 } __attribute__((aligned(sizeof(long))));
30     /* The alignment might seem pointless, but allegedly CRIS needs it */
31 
32 struct rb_root {
33 	struct rb_node *rb_node;
34 };
35 
36 
37 #define rb_parent(r)   ((struct rb_node *)((r)->__rb_parent_color & ~3))
38 
39 #define RB_ROOT	(struct rb_root) { NULL, }
40 #define	rb_entry(ptr, type, member) container_of(ptr, type, member)
41 
42 #define RB_EMPTY_ROOT(root)  ((root)->rb_node == NULL)
43 
44 /* 'empty' nodes are nodes that are known not to be inserted in an rbree */
45 #define RB_EMPTY_NODE(node)  \
46 	((node)->__rb_parent_color == (unsigned long)(node))
47 #define RB_CLEAR_NODE(node)  \
48 	((node)->__rb_parent_color = (unsigned long)(node))
49 
50 
51 extern void rb_insert_color(struct rb_node *, struct rb_root *);
52 extern void rb_erase(struct rb_node *, struct rb_root *);
53 
54 
55 /* Find logical next and previous nodes in a tree */
56 extern struct rb_node *rb_next(const struct rb_node *);
57 extern struct rb_node *rb_prev(const struct rb_node *);
58 extern struct rb_node *rb_first(const struct rb_root *);
59 extern struct rb_node *rb_last(const struct rb_root *);
60 
61 /* Postorder iteration - always visit the parent after its children */
62 extern struct rb_node *rb_first_postorder(const struct rb_root *);
63 extern struct rb_node *rb_next_postorder(const struct rb_node *);
64 
65 /* Fast replacement of a single node without remove/rebalance/add/rebalance */
66 extern void rb_replace_node(struct rb_node *victim, struct rb_node *new,
67 			    struct rb_root *root);
68 
69 static inline void rb_link_node(struct rb_node * node, struct rb_node * parent,
70 				struct rb_node ** rb_link)
71 {
72 	node->__rb_parent_color = (unsigned long)parent;
73 	node->rb_left = node->rb_right = NULL;
74 
75 	*rb_link = node;
76 }
77 
78 #define rb_entry_safe(ptr, type, member) \
79 	({ typeof(ptr) ____ptr = (ptr); \
80 	   ____ptr ? rb_entry(____ptr, type, member) : NULL; \
81 	})
82 
83 /**
84  * rbtree_postorder_for_each_entry_safe - iterate over rb_root in post order of
85  * given type safe against removal of rb_node entry
86  *
87  * @pos:	the 'type *' to use as a loop cursor.
88  * @n:		another 'type *' to use as temporary storage
89  * @root:	'rb_root *' of the rbtree.
90  * @field:	the name of the rb_node field within 'type'.
91  */
92 #define rbtree_postorder_for_each_entry_safe(pos, n, root, field) \
93 	for (pos = rb_entry_safe(rb_first_postorder(root), typeof(*pos), field); \
94 	     pos && ({ n = rb_entry_safe(rb_next_postorder(&pos->field), \
95 			typeof(*pos), field); 1; }); \
96 	     pos = n)
97 
98 #endif	/* _LINUX_RBTREE_H */
99