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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 | ||
27 | #include <linux/rbtree.h> | |
28 | ||
29 | /* | |
30 | * Please note - only struct rb_augment_callbacks and the prototypes for | |
31 | * rb_insert_augmented() and rb_erase_augmented() are intended to be public. | |
32 | * The rest are implementation details you are not expected to depend on. | |
33 | * | |
34 | * See Documentation/rbtree.txt for documentation and samples. | |
35 | */ | |
36 | ||
37 | struct rb_augment_callbacks { | |
38 | void (*propagate)(struct rb_node *node, struct rb_node *stop); | |
39 | void (*copy)(struct rb_node *old, struct rb_node *new); | |
40 | void (*rotate)(struct rb_node *old, struct rb_node *new); | |
41 | }; | |
42 | ||
43 | extern void __rb_insert_augmented(struct rb_node *node, struct rb_root *root, | |
44 | void (*augment_rotate)(struct rb_node *old, struct rb_node *new)); | |
45 | static inline void | |
46 | rb_insert_augmented(struct rb_node *node, struct rb_root *root, | |
47 | const struct rb_augment_callbacks *augment) | |
48 | { | |
49 | __rb_insert_augmented(node, root, augment->rotate); | |
50 | } | |
51 | ||
52 | #define RB_DECLARE_CALLBACKS(rbstatic, rbname, rbstruct, rbfield, \ | |
53 | rbtype, rbaugmented, rbcompute) \ | |
54 | static inline void \ | |
55 | rbname ## _propagate(struct rb_node *rb, struct rb_node *stop) \ | |
56 | { \ | |
57 | while (rb != stop) { \ | |
58 | rbstruct *node = rb_entry(rb, rbstruct, rbfield); \ | |
59 | rbtype augmented = rbcompute(node); \ | |
60 | if (node->rbaugmented == augmented) \ | |
61 | break; \ | |
62 | node->rbaugmented = augmented; \ | |
63 | rb = rb_parent(&node->rbfield); \ | |
64 | } \ | |
65 | } \ | |
66 | static inline void \ | |
67 | rbname ## _copy(struct rb_node *rb_old, struct rb_node *rb_new) \ | |
68 | { \ | |
69 | rbstruct *old = rb_entry(rb_old, rbstruct, rbfield); \ | |
70 | rbstruct *new = rb_entry(rb_new, rbstruct, rbfield); \ | |
71 | new->rbaugmented = old->rbaugmented; \ | |
72 | } \ | |
73 | static void \ | |
74 | rbname ## _rotate(struct rb_node *rb_old, struct rb_node *rb_new) \ | |
75 | { \ | |
76 | rbstruct *old = rb_entry(rb_old, rbstruct, rbfield); \ | |
77 | rbstruct *new = rb_entry(rb_new, rbstruct, rbfield); \ | |
78 | new->rbaugmented = old->rbaugmented; \ | |
79 | old->rbaugmented = rbcompute(old); \ | |
80 | } \ | |
81 | rbstatic const struct rb_augment_callbacks rbname = { \ | |
82 | rbname ## _propagate, rbname ## _copy, rbname ## _rotate \ | |
83 | }; | |
84 | ||
85 | ||
86 | #define RB_RED 0 | |
87 | #define RB_BLACK 1 | |
88 | ||
89 | #define __rb_parent(pc) ((struct rb_node *)(pc & ~3)) | |
90 | ||
91 | #define __rb_color(pc) ((pc) & 1) | |
92 | #define __rb_is_black(pc) __rb_color(pc) | |
93 | #define __rb_is_red(pc) (!__rb_color(pc)) | |
94 | #define rb_color(rb) __rb_color((rb)->__rb_parent_color) | |
95 | #define rb_is_red(rb) __rb_is_red((rb)->__rb_parent_color) | |
96 | #define rb_is_black(rb) __rb_is_black((rb)->__rb_parent_color) | |
97 | ||
98 | static inline void rb_set_parent(struct rb_node *rb, struct rb_node *p) | |
99 | { | |
100 | rb->__rb_parent_color = rb_color(rb) | (unsigned long)p; | |
101 | } | |
102 | ||
103 | static inline void rb_set_parent_color(struct rb_node *rb, | |
104 | struct rb_node *p, int color) | |
105 | { | |
106 | rb->__rb_parent_color = (unsigned long)p | color; | |
107 | } | |
108 | ||
109 | static inline void | |
110 | __rb_change_child(struct rb_node *old, struct rb_node *new, | |
111 | struct rb_node *parent, struct rb_root *root) | |
112 | { | |
113 | if (parent) { | |
114 | if (parent->rb_left == old) | |
115 | parent->rb_left = new; | |
116 | else | |
117 | parent->rb_right = new; | |
118 | } else | |
119 | root->rb_node = new; | |
120 | } | |
121 | ||
122 | extern void __rb_erase_color(struct rb_node *parent, struct rb_root *root, | |
123 | void (*augment_rotate)(struct rb_node *old, struct rb_node *new)); | |
124 | ||
125 | static __always_inline void | |
126 | rb_erase_augmented(struct rb_node *node, struct rb_root *root, | |
127 | const struct rb_augment_callbacks *augment) | |
128 | { | |
129 | struct rb_node *child = node->rb_right, *tmp = node->rb_left; | |
130 | struct rb_node *parent, *rebalance; | |
131 | unsigned long pc; | |
132 | ||
133 | if (!tmp) { | |
134 | /* | |
135 | * Case 1: node to erase has no more than 1 child (easy!) | |
136 | * | |
137 | * Note that if there is one child it must be red due to 5) | |
138 | * and node must be black due to 4). We adjust colors locally | |
139 | * so as to bypass __rb_erase_color() later on. | |
140 | */ | |
141 | pc = node->__rb_parent_color; | |
142 | parent = __rb_parent(pc); | |
143 | __rb_change_child(node, child, parent, root); | |
144 | if (child) { | |
145 | child->__rb_parent_color = pc; | |
146 | rebalance = NULL; | |
147 | } else | |
148 | rebalance = __rb_is_black(pc) ? parent : NULL; | |
149 | tmp = parent; | |
150 | } else if (!child) { | |
151 | /* Still case 1, but this time the child is node->rb_left */ | |
152 | tmp->__rb_parent_color = pc = node->__rb_parent_color; | |
153 | parent = __rb_parent(pc); | |
154 | __rb_change_child(node, tmp, parent, root); | |
155 | rebalance = NULL; | |
156 | tmp = parent; | |
157 | } else { | |
158 | struct rb_node *successor = child, *child2; | |
159 | tmp = child->rb_left; | |
160 | if (!tmp) { | |
161 | /* | |
162 | * Case 2: node's successor is its right child | |
163 | * | |
164 | * (n) (s) | |
165 | * / \ / \ | |
166 | * (x) (s) -> (x) (c) | |
167 | * \ | |
168 | * (c) | |
169 | */ | |
170 | parent = successor; | |
171 | child2 = successor->rb_right; | |
172 | augment->copy(node, successor); | |
173 | } else { | |
174 | /* | |
175 | * Case 3: node's successor is leftmost under | |
176 | * node's right child subtree | |
177 | * | |
178 | * (n) (s) | |
179 | * / \ / \ | |
180 | * (x) (y) -> (x) (y) | |
181 | * / / | |
182 | * (p) (p) | |
183 | * / / | |
184 | * (s) (c) | |
185 | * \ | |
186 | * (c) | |
187 | */ | |
188 | do { | |
189 | parent = successor; | |
190 | successor = tmp; | |
191 | tmp = tmp->rb_left; | |
192 | } while (tmp); | |
193 | parent->rb_left = child2 = successor->rb_right; | |
194 | successor->rb_right = child; | |
195 | rb_set_parent(child, successor); | |
196 | augment->copy(node, successor); | |
197 | augment->propagate(parent, successor); | |
198 | } | |
199 | ||
200 | successor->rb_left = tmp = node->rb_left; | |
201 | rb_set_parent(tmp, successor); | |
202 | ||
203 | pc = node->__rb_parent_color; | |
204 | tmp = __rb_parent(pc); | |
205 | __rb_change_child(node, successor, tmp, root); | |
206 | if (child2) { | |
207 | successor->__rb_parent_color = pc; | |
208 | rb_set_parent_color(child2, parent, RB_BLACK); | |
209 | rebalance = NULL; | |
210 | } else { | |
211 | unsigned long pc2 = successor->__rb_parent_color; | |
212 | successor->__rb_parent_color = pc; | |
213 | rebalance = __rb_is_black(pc2) ? parent : NULL; | |
214 | } | |
215 | tmp = successor; | |
216 | } | |
217 | ||
218 | augment->propagate(tmp, NULL); | |
219 | if (rebalance) | |
220 | __rb_erase_color(rebalance, root, augment->rotate); | |
221 | } | |
222 | ||
223 | #endif /* _LINUX_RBTREE_AUGMENTED_H */ |