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9c079add ML |
1 | /* |
2 | Red Black Trees | |
3 | (C) 1999 Andrea Arcangeli <andrea@suse.de> | |
4 | (C) 2002 David Woodhouse <dwmw2@infradead.org> | |
5 | (C) 2012 Michel Lespinasse <walken@google.com> | |
6 | ||
7 | This program is free software; you can redistribute it and/or modify | |
8 | it under the terms of the GNU General Public License as published by | |
9 | the Free Software Foundation; either version 2 of the License, or | |
10 | (at your option) any later version. | |
11 | ||
12 | This program is distributed in the hope that it will be useful, | |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | GNU General Public License for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
18 | along with this program; if not, write to the Free Software | |
19 | Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
20 | ||
21 | linux/include/linux/rbtree_augmented.h | |
22 | */ | |
23 | ||
24 | #ifndef _LINUX_RBTREE_AUGMENTED_H | |
25 | #define _LINUX_RBTREE_AUGMENTED_H | |
26 | ||
29fc7c5a | 27 | #include <linux/compiler.h> |
9c079add | 28 | #include <linux/rbtree.h> |
2075b16e | 29 | #include <linux/rcupdate.h> |
9c079add ML |
30 | |
31 | /* | |
32 | * Please note - only struct rb_augment_callbacks and the prototypes for | |
33 | * rb_insert_augmented() and rb_erase_augmented() are intended to be public. | |
34 | * The rest are implementation details you are not expected to depend on. | |
35 | * | |
36 | * See Documentation/rbtree.txt for documentation and samples. | |
37 | */ | |
38 | ||
39 | struct rb_augment_callbacks { | |
40 | void (*propagate)(struct rb_node *node, struct rb_node *stop); | |
41 | void (*copy)(struct rb_node *old, struct rb_node *new); | |
42 | void (*rotate)(struct rb_node *old, struct rb_node *new); | |
43 | }; | |
44 | ||
cd9e61ed DB |
45 | extern void __rb_insert_augmented(struct rb_node *node, |
46 | struct rb_root *root, | |
47 | bool newleft, struct rb_node **leftmost, | |
9c079add | 48 | void (*augment_rotate)(struct rb_node *old, struct rb_node *new)); |
a841b659 LJ |
49 | /* |
50 | * Fixup the rbtree and update the augmented information when rebalancing. | |
51 | * | |
52 | * On insertion, the user must update the augmented information on the path | |
53 | * leading to the inserted node, then call rb_link_node() as usual and | |
54 | * rb_augment_inserted() instead of the usual rb_insert_color() call. | |
55 | * If rb_augment_inserted() rebalances the rbtree, it will callback into | |
56 | * a user provided function to update the augmented information on the | |
57 | * affected subtrees. | |
58 | */ | |
9c079add ML |
59 | static inline void |
60 | rb_insert_augmented(struct rb_node *node, struct rb_root *root, | |
61 | const struct rb_augment_callbacks *augment) | |
62 | { | |
cd9e61ed DB |
63 | __rb_insert_augmented(node, root, false, NULL, augment->rotate); |
64 | } | |
65 | ||
66 | static inline void | |
67 | rb_insert_augmented_cached(struct rb_node *node, | |
68 | struct rb_root_cached *root, bool newleft, | |
69 | const struct rb_augment_callbacks *augment) | |
70 | { | |
71 | __rb_insert_augmented(node, &root->rb_root, | |
72 | newleft, &root->rb_leftmost, augment->rotate); | |
9c079add ML |
73 | } |
74 | ||
75 | #define RB_DECLARE_CALLBACKS(rbstatic, rbname, rbstruct, rbfield, \ | |
76 | rbtype, rbaugmented, rbcompute) \ | |
77 | static inline void \ | |
78 | rbname ## _propagate(struct rb_node *rb, struct rb_node *stop) \ | |
79 | { \ | |
80 | while (rb != stop) { \ | |
81 | rbstruct *node = rb_entry(rb, rbstruct, rbfield); \ | |
82 | rbtype augmented = rbcompute(node); \ | |
83 | if (node->rbaugmented == augmented) \ | |
84 | break; \ | |
85 | node->rbaugmented = augmented; \ | |
86 | rb = rb_parent(&node->rbfield); \ | |
87 | } \ | |
88 | } \ | |
89 | static inline void \ | |
90 | rbname ## _copy(struct rb_node *rb_old, struct rb_node *rb_new) \ | |
91 | { \ | |
92 | rbstruct *old = rb_entry(rb_old, rbstruct, rbfield); \ | |
93 | rbstruct *new = rb_entry(rb_new, rbstruct, rbfield); \ | |
94 | new->rbaugmented = old->rbaugmented; \ | |
95 | } \ | |
96 | static void \ | |
97 | rbname ## _rotate(struct rb_node *rb_old, struct rb_node *rb_new) \ | |
98 | { \ | |
99 | rbstruct *old = rb_entry(rb_old, rbstruct, rbfield); \ | |
100 | rbstruct *new = rb_entry(rb_new, rbstruct, rbfield); \ | |
101 | new->rbaugmented = old->rbaugmented; \ | |
102 | old->rbaugmented = rbcompute(old); \ | |
103 | } \ | |
104 | rbstatic const struct rb_augment_callbacks rbname = { \ | |
f231aebf KC |
105 | .propagate = rbname ## _propagate, \ |
106 | .copy = rbname ## _copy, \ | |
107 | .rotate = rbname ## _rotate \ | |
9c079add ML |
108 | }; |
109 | ||
110 | ||
111 | #define RB_RED 0 | |
112 | #define RB_BLACK 1 | |
113 | ||
114 | #define __rb_parent(pc) ((struct rb_node *)(pc & ~3)) | |
115 | ||
116 | #define __rb_color(pc) ((pc) & 1) | |
117 | #define __rb_is_black(pc) __rb_color(pc) | |
118 | #define __rb_is_red(pc) (!__rb_color(pc)) | |
119 | #define rb_color(rb) __rb_color((rb)->__rb_parent_color) | |
120 | #define rb_is_red(rb) __rb_is_red((rb)->__rb_parent_color) | |
121 | #define rb_is_black(rb) __rb_is_black((rb)->__rb_parent_color) | |
122 | ||
123 | static inline void rb_set_parent(struct rb_node *rb, struct rb_node *p) | |
124 | { | |
125 | rb->__rb_parent_color = rb_color(rb) | (unsigned long)p; | |
126 | } | |
127 | ||
128 | static inline void rb_set_parent_color(struct rb_node *rb, | |
129 | struct rb_node *p, int color) | |
130 | { | |
131 | rb->__rb_parent_color = (unsigned long)p | color; | |
132 | } | |
133 | ||
134 | static inline void | |
135 | __rb_change_child(struct rb_node *old, struct rb_node *new, | |
136 | struct rb_node *parent, struct rb_root *root) | |
137 | { | |
138 | if (parent) { | |
139 | if (parent->rb_left == old) | |
d72da4a4 | 140 | WRITE_ONCE(parent->rb_left, new); |
9c079add | 141 | else |
d72da4a4 | 142 | WRITE_ONCE(parent->rb_right, new); |
9c079add | 143 | } else |
d72da4a4 | 144 | WRITE_ONCE(root->rb_node, new); |
9c079add ML |
145 | } |
146 | ||
c1adf200 DH |
147 | static inline void |
148 | __rb_change_child_rcu(struct rb_node *old, struct rb_node *new, | |
149 | struct rb_node *parent, struct rb_root *root) | |
150 | { | |
151 | if (parent) { | |
152 | if (parent->rb_left == old) | |
153 | rcu_assign_pointer(parent->rb_left, new); | |
154 | else | |
155 | rcu_assign_pointer(parent->rb_right, new); | |
156 | } else | |
157 | rcu_assign_pointer(root->rb_node, new); | |
158 | } | |
159 | ||
9c079add ML |
160 | extern void __rb_erase_color(struct rb_node *parent, struct rb_root *root, |
161 | void (*augment_rotate)(struct rb_node *old, struct rb_node *new)); | |
162 | ||
3cb7a563 ML |
163 | static __always_inline struct rb_node * |
164 | __rb_erase_augmented(struct rb_node *node, struct rb_root *root, | |
cd9e61ed | 165 | struct rb_node **leftmost, |
3cb7a563 | 166 | const struct rb_augment_callbacks *augment) |
9c079add | 167 | { |
d72da4a4 PZ |
168 | struct rb_node *child = node->rb_right; |
169 | struct rb_node *tmp = node->rb_left; | |
9c079add ML |
170 | struct rb_node *parent, *rebalance; |
171 | unsigned long pc; | |
172 | ||
cd9e61ed DB |
173 | if (leftmost && node == *leftmost) |
174 | *leftmost = rb_next(node); | |
175 | ||
9c079add ML |
176 | if (!tmp) { |
177 | /* | |
178 | * Case 1: node to erase has no more than 1 child (easy!) | |
179 | * | |
180 | * Note that if there is one child it must be red due to 5) | |
181 | * and node must be black due to 4). We adjust colors locally | |
182 | * so as to bypass __rb_erase_color() later on. | |
183 | */ | |
184 | pc = node->__rb_parent_color; | |
185 | parent = __rb_parent(pc); | |
186 | __rb_change_child(node, child, parent, root); | |
187 | if (child) { | |
188 | child->__rb_parent_color = pc; | |
189 | rebalance = NULL; | |
190 | } else | |
191 | rebalance = __rb_is_black(pc) ? parent : NULL; | |
192 | tmp = parent; | |
193 | } else if (!child) { | |
194 | /* Still case 1, but this time the child is node->rb_left */ | |
195 | tmp->__rb_parent_color = pc = node->__rb_parent_color; | |
196 | parent = __rb_parent(pc); | |
197 | __rb_change_child(node, tmp, parent, root); | |
198 | rebalance = NULL; | |
199 | tmp = parent; | |
200 | } else { | |
201 | struct rb_node *successor = child, *child2; | |
d72da4a4 | 202 | |
9c079add ML |
203 | tmp = child->rb_left; |
204 | if (!tmp) { | |
205 | /* | |
206 | * Case 2: node's successor is its right child | |
207 | * | |
208 | * (n) (s) | |
209 | * / \ / \ | |
210 | * (x) (s) -> (x) (c) | |
211 | * \ | |
212 | * (c) | |
213 | */ | |
214 | parent = successor; | |
215 | child2 = successor->rb_right; | |
d72da4a4 | 216 | |
9c079add ML |
217 | augment->copy(node, successor); |
218 | } else { | |
219 | /* | |
220 | * Case 3: node's successor is leftmost under | |
221 | * node's right child subtree | |
222 | * | |
223 | * (n) (s) | |
224 | * / \ / \ | |
225 | * (x) (y) -> (x) (y) | |
226 | * / / | |
227 | * (p) (p) | |
228 | * / / | |
229 | * (s) (c) | |
230 | * \ | |
231 | * (c) | |
232 | */ | |
233 | do { | |
234 | parent = successor; | |
235 | successor = tmp; | |
236 | tmp = tmp->rb_left; | |
237 | } while (tmp); | |
d72da4a4 PZ |
238 | child2 = successor->rb_right; |
239 | WRITE_ONCE(parent->rb_left, child2); | |
240 | WRITE_ONCE(successor->rb_right, child); | |
9c079add | 241 | rb_set_parent(child, successor); |
d72da4a4 | 242 | |
9c079add ML |
243 | augment->copy(node, successor); |
244 | augment->propagate(parent, successor); | |
245 | } | |
246 | ||
d72da4a4 PZ |
247 | tmp = node->rb_left; |
248 | WRITE_ONCE(successor->rb_left, tmp); | |
9c079add ML |
249 | rb_set_parent(tmp, successor); |
250 | ||
251 | pc = node->__rb_parent_color; | |
252 | tmp = __rb_parent(pc); | |
253 | __rb_change_child(node, successor, tmp, root); | |
d72da4a4 | 254 | |
9c079add ML |
255 | if (child2) { |
256 | successor->__rb_parent_color = pc; | |
257 | rb_set_parent_color(child2, parent, RB_BLACK); | |
258 | rebalance = NULL; | |
259 | } else { | |
260 | unsigned long pc2 = successor->__rb_parent_color; | |
261 | successor->__rb_parent_color = pc; | |
262 | rebalance = __rb_is_black(pc2) ? parent : NULL; | |
263 | } | |
264 | tmp = successor; | |
265 | } | |
266 | ||
267 | augment->propagate(tmp, NULL); | |
3cb7a563 ML |
268 | return rebalance; |
269 | } | |
270 | ||
271 | static __always_inline void | |
272 | rb_erase_augmented(struct rb_node *node, struct rb_root *root, | |
273 | const struct rb_augment_callbacks *augment) | |
274 | { | |
cd9e61ed DB |
275 | struct rb_node *rebalance = __rb_erase_augmented(node, root, |
276 | NULL, augment); | |
9c079add ML |
277 | if (rebalance) |
278 | __rb_erase_color(rebalance, root, augment->rotate); | |
279 | } | |
280 | ||
cd9e61ed DB |
281 | static __always_inline void |
282 | rb_erase_augmented_cached(struct rb_node *node, struct rb_root_cached *root, | |
283 | const struct rb_augment_callbacks *augment) | |
284 | { | |
285 | struct rb_node *rebalance = __rb_erase_augmented(node, &root->rb_root, | |
286 | &root->rb_leftmost, | |
287 | augment); | |
288 | if (rebalance) | |
289 | __rb_erase_color(rebalance, &root->rb_root, augment->rotate); | |
290 | } | |
291 | ||
9c079add | 292 | #endif /* _LINUX_RBTREE_AUGMENTED_H */ |