Commit | Line | Data |
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1da177e4 LT |
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 | ||
1457d287 | 26 | See Documentation/rbtree.txt for documentation and samples. |
1da177e4 LT |
27 | */ |
28 | ||
29 | #ifndef _LINUX_RBTREE_H | |
30 | #define _LINUX_RBTREE_H | |
31 | ||
32 | #include <linux/kernel.h> | |
33 | #include <linux/stddef.h> | |
d72da4a4 | 34 | #include <linux/rcupdate.h> |
1da177e4 | 35 | |
bf7ad8ee ML |
36 | struct rb_node { |
37 | unsigned long __rb_parent_color; | |
1da177e4 LT |
38 | struct rb_node *rb_right; |
39 | struct rb_node *rb_left; | |
e977145a DW |
40 | } __attribute__((aligned(sizeof(long)))); |
41 | /* The alignment might seem pointless, but allegedly CRIS needs it */ | |
1da177e4 | 42 | |
bf7ad8ee | 43 | struct rb_root { |
1da177e4 LT |
44 | struct rb_node *rb_node; |
45 | }; | |
46 | ||
cd9e61ed DB |
47 | /* |
48 | * Leftmost-cached rbtrees. | |
49 | * | |
50 | * We do not cache the rightmost node based on footprint | |
51 | * size vs number of potential users that could benefit | |
52 | * from O(1) rb_last(). Just not worth it, users that want | |
53 | * this feature can always implement the logic explicitly. | |
54 | * Furthermore, users that want to cache both pointers may | |
55 | * find it a bit asymmetric, but that's ok. | |
56 | */ | |
57 | struct rb_root_cached { | |
58 | struct rb_root rb_root; | |
59 | struct rb_node *rb_leftmost; | |
60 | }; | |
55a98102 | 61 | |
bf7ad8ee | 62 | #define rb_parent(r) ((struct rb_node *)((r)->__rb_parent_color & ~3)) |
55a98102 | 63 | |
b945d6b2 | 64 | #define RB_ROOT (struct rb_root) { NULL, } |
cd9e61ed | 65 | #define RB_ROOT_CACHED (struct rb_root_cached) { {NULL, }, NULL } |
1da177e4 LT |
66 | #define rb_entry(ptr, type, member) container_of(ptr, type, member) |
67 | ||
a460bece | 68 | #define RB_EMPTY_ROOT(root) (READ_ONCE((root)->rb_node) == NULL) |
4c199a93 | 69 | |
7647f14f | 70 | /* 'empty' nodes are nodes that are known not to be inserted in an rbtree */ |
bf7ad8ee ML |
71 | #define RB_EMPTY_NODE(node) \ |
72 | ((node)->__rb_parent_color == (unsigned long)(node)) | |
73 | #define RB_CLEAR_NODE(node) \ | |
74 | ((node)->__rb_parent_color = (unsigned long)(node)) | |
dd67d051 | 75 | |
88d19cf3 | 76 | |
1da177e4 LT |
77 | extern void rb_insert_color(struct rb_node *, struct rb_root *); |
78 | extern void rb_erase(struct rb_node *, struct rb_root *); | |
79 | ||
14b94af0 | 80 | |
1da177e4 | 81 | /* Find logical next and previous nodes in a tree */ |
f4b477c4 AB |
82 | extern struct rb_node *rb_next(const struct rb_node *); |
83 | extern struct rb_node *rb_prev(const struct rb_node *); | |
84 | extern struct rb_node *rb_first(const struct rb_root *); | |
85 | extern struct rb_node *rb_last(const struct rb_root *); | |
1da177e4 | 86 | |
cd9e61ed DB |
87 | extern void rb_insert_color_cached(struct rb_node *, |
88 | struct rb_root_cached *, bool); | |
89 | extern void rb_erase_cached(struct rb_node *node, struct rb_root_cached *); | |
90 | /* Same as rb_first(), but O(1) */ | |
91 | #define rb_first_cached(root) (root)->rb_leftmost | |
92 | ||
9dee5c51 CS |
93 | /* Postorder iteration - always visit the parent after its children */ |
94 | extern struct rb_node *rb_first_postorder(const struct rb_root *); | |
95 | extern struct rb_node *rb_next_postorder(const struct rb_node *); | |
96 | ||
1da177e4 | 97 | /* Fast replacement of a single node without remove/rebalance/add/rebalance */ |
d72da4a4 | 98 | extern void rb_replace_node(struct rb_node *victim, struct rb_node *new, |
1da177e4 | 99 | struct rb_root *root); |
c1adf200 DH |
100 | extern void rb_replace_node_rcu(struct rb_node *victim, struct rb_node *new, |
101 | struct rb_root *root); | |
338f1d9d CW |
102 | extern void rb_replace_node_cached(struct rb_node *victim, struct rb_node *new, |
103 | struct rb_root_cached *root); | |
1da177e4 | 104 | |
d72da4a4 PZ |
105 | static inline void rb_link_node(struct rb_node *node, struct rb_node *parent, |
106 | struct rb_node **rb_link) | |
1da177e4 | 107 | { |
bf7ad8ee | 108 | node->__rb_parent_color = (unsigned long)parent; |
1da177e4 LT |
109 | node->rb_left = node->rb_right = NULL; |
110 | ||
111 | *rb_link = node; | |
112 | } | |
113 | ||
d72da4a4 PZ |
114 | static inline void rb_link_node_rcu(struct rb_node *node, struct rb_node *parent, |
115 | struct rb_node **rb_link) | |
116 | { | |
117 | node->__rb_parent_color = (unsigned long)parent; | |
118 | node->rb_left = node->rb_right = NULL; | |
119 | ||
120 | rcu_assign_pointer(*rb_link, node); | |
121 | } | |
122 | ||
1310a5a9 JK |
123 | #define rb_entry_safe(ptr, type, member) \ |
124 | ({ typeof(ptr) ____ptr = (ptr); \ | |
125 | ____ptr ? rb_entry(____ptr, type, member) : NULL; \ | |
126 | }) | |
127 | ||
2b529089 | 128 | /** |
8de1ee7e CS |
129 | * rbtree_postorder_for_each_entry_safe - iterate in post-order over rb_root of |
130 | * given type allowing the backing memory of @pos to be invalidated | |
2b529089 CS |
131 | * |
132 | * @pos: the 'type *' to use as a loop cursor. | |
133 | * @n: another 'type *' to use as temporary storage | |
134 | * @root: 'rb_root *' of the rbtree. | |
135 | * @field: the name of the rb_node field within 'type'. | |
8de1ee7e CS |
136 | * |
137 | * rbtree_postorder_for_each_entry_safe() provides a similar guarantee as | |
138 | * list_for_each_entry_safe() and allows the iteration to continue independent | |
139 | * of changes to @pos by the body of the loop. | |
140 | * | |
141 | * Note, however, that it cannot handle other modifications that re-order the | |
142 | * rbtree it is iterating over. This includes calling rb_erase() on @pos, as | |
143 | * rb_erase() may rebalance the tree, causing us to miss some nodes. | |
2b529089 CS |
144 | */ |
145 | #define rbtree_postorder_for_each_entry_safe(pos, n, root, field) \ | |
1310a5a9 JK |
146 | for (pos = rb_entry_safe(rb_first_postorder(root), typeof(*pos), field); \ |
147 | pos && ({ n = rb_entry_safe(rb_next_postorder(&pos->field), \ | |
148 | typeof(*pos), field); 1; }); \ | |
149 | pos = n) | |
2b529089 | 150 | |
1da177e4 | 151 | #endif /* _LINUX_RBTREE_H */ |