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