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 tools/linux/include/linux/rbtree_augmented.h
22
23 Copied from:
24 linux/include/linux/rbtree_augmented.h
25 */
26
27 #ifndef _TOOLS_LINUX_RBTREE_AUGMENTED_H
28 #define _TOOLS_LINUX_RBTREE_AUGMENTED_H
29
30 #include <linux/compiler.h>
31 #include <linux/rbtree.h>
32
33 /*
34 * Please note - only struct rb_augment_callbacks and the prototypes for
35 * rb_insert_augmented() and rb_erase_augmented() are intended to be public.
36 * The rest are implementation details you are not expected to depend on.
37 *
38 * See Documentation/rbtree.txt for documentation and samples.
39 */
40
41 struct rb_augment_callbacks {
42 void (*propagate)(struct rb_node *node, struct rb_node *stop);
43 void (*copy)(struct rb_node *old, struct rb_node *new);
44 void (*rotate)(struct rb_node *old, struct rb_node *new);
45 };
46
47 extern void __rb_insert_augmented(struct rb_node *node, struct rb_root *root,
48 void (*augment_rotate)(struct rb_node *old, struct rb_node *new));
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 */
59 static inline void
rb_insert_augmented(struct rb_node * node,struct rb_root * root,const struct rb_augment_callbacks * augment)60 rb_insert_augmented(struct rb_node *node, struct rb_root *root,
61 const struct rb_augment_callbacks *augment)
62 {
63 __rb_insert_augmented(node, root, augment->rotate);
64 }
65
66 #define RB_DECLARE_CALLBACKS(rbstatic, rbname, rbstruct, rbfield, \
67 rbtype, rbaugmented, rbcompute) \
68 static inline void \
69 rbname ## _propagate(struct rb_node *rb, struct rb_node *stop) \
70 { \
71 while (rb != stop) { \
72 rbstruct *node = rb_entry(rb, rbstruct, rbfield); \
73 rbtype augmented = rbcompute(node); \
74 if (node->rbaugmented == augmented) \
75 break; \
76 node->rbaugmented = augmented; \
77 rb = rb_parent(&node->rbfield); \
78 } \
79 } \
80 static inline void \
81 rbname ## _copy(struct rb_node *rb_old, struct rb_node *rb_new) \
82 { \
83 rbstruct *old = rb_entry(rb_old, rbstruct, rbfield); \
84 rbstruct *new = rb_entry(rb_new, rbstruct, rbfield); \
85 new->rbaugmented = old->rbaugmented; \
86 } \
87 static void \
88 rbname ## _rotate(struct rb_node *rb_old, struct rb_node *rb_new) \
89 { \
90 rbstruct *old = rb_entry(rb_old, rbstruct, rbfield); \
91 rbstruct *new = rb_entry(rb_new, rbstruct, rbfield); \
92 new->rbaugmented = old->rbaugmented; \
93 old->rbaugmented = rbcompute(old); \
94 } \
95 rbstatic const struct rb_augment_callbacks rbname = { \
96 rbname ## _propagate, rbname ## _copy, rbname ## _rotate \
97 };
98
99
100 #define RB_RED 0
101 #define RB_BLACK 1
102
103 #define __rb_parent(pc) ((struct rb_node *)(pc & ~3))
104
105 #define __rb_color(pc) ((pc) & 1)
106 #define __rb_is_black(pc) __rb_color(pc)
107 #define __rb_is_red(pc) (!__rb_color(pc))
108 #define rb_color(rb) __rb_color((rb)->__rb_parent_color)
109 #define rb_is_red(rb) __rb_is_red((rb)->__rb_parent_color)
110 #define rb_is_black(rb) __rb_is_black((rb)->__rb_parent_color)
111
rb_set_parent(struct rb_node * rb,struct rb_node * p)112 static inline void rb_set_parent(struct rb_node *rb, struct rb_node *p)
113 {
114 rb->__rb_parent_color = rb_color(rb) | (unsigned long)p;
115 }
116
rb_set_parent_color(struct rb_node * rb,struct rb_node * p,int color)117 static inline void rb_set_parent_color(struct rb_node *rb,
118 struct rb_node *p, int color)
119 {
120 rb->__rb_parent_color = (unsigned long)p | color;
121 }
122
123 static inline void
__rb_change_child(struct rb_node * old,struct rb_node * new,struct rb_node * parent,struct rb_root * root)124 __rb_change_child(struct rb_node *old, struct rb_node *new,
125 struct rb_node *parent, struct rb_root *root)
126 {
127 if (parent) {
128 if (parent->rb_left == old)
129 parent->rb_left = new;
130 else
131 parent->rb_right = new;
132 } else
133 root->rb_node = new;
134 }
135
136 extern void __rb_erase_color(struct rb_node *parent, struct rb_root *root,
137 void (*augment_rotate)(struct rb_node *old, struct rb_node *new));
138
139 static __always_inline struct rb_node *
__rb_erase_augmented(struct rb_node * node,struct rb_root * root,const struct rb_augment_callbacks * augment)140 __rb_erase_augmented(struct rb_node *node, struct rb_root *root,
141 const struct rb_augment_callbacks *augment)
142 {
143 struct rb_node *child = node->rb_right, *tmp = node->rb_left;
144 struct rb_node *parent, *rebalance;
145 unsigned long pc;
146
147 if (!tmp) {
148 /*
149 * Case 1: node to erase has no more than 1 child (easy!)
150 *
151 * Note that if there is one child it must be red due to 5)
152 * and node must be black due to 4). We adjust colors locally
153 * so as to bypass __rb_erase_color() later on.
154 */
155 pc = node->__rb_parent_color;
156 parent = __rb_parent(pc);
157 __rb_change_child(node, child, parent, root);
158 if (child) {
159 child->__rb_parent_color = pc;
160 rebalance = NULL;
161 } else
162 rebalance = __rb_is_black(pc) ? parent : NULL;
163 tmp = parent;
164 } else if (!child) {
165 /* Still case 1, but this time the child is node->rb_left */
166 tmp->__rb_parent_color = pc = node->__rb_parent_color;
167 parent = __rb_parent(pc);
168 __rb_change_child(node, tmp, parent, root);
169 rebalance = NULL;
170 tmp = parent;
171 } else {
172 struct rb_node *successor = child, *child2;
173 tmp = child->rb_left;
174 if (!tmp) {
175 /*
176 * Case 2: node's successor is its right child
177 *
178 * (n) (s)
179 * / \ / \
180 * (x) (s) -> (x) (c)
181 * \
182 * (c)
183 */
184 parent = successor;
185 child2 = successor->rb_right;
186 augment->copy(node, successor);
187 } else {
188 /*
189 * Case 3: node's successor is leftmost under
190 * node's right child subtree
191 *
192 * (n) (s)
193 * / \ / \
194 * (x) (y) -> (x) (y)
195 * / /
196 * (p) (p)
197 * / /
198 * (s) (c)
199 * \
200 * (c)
201 */
202 do {
203 parent = successor;
204 successor = tmp;
205 tmp = tmp->rb_left;
206 } while (tmp);
207 parent->rb_left = child2 = successor->rb_right;
208 successor->rb_right = child;
209 rb_set_parent(child, successor);
210 augment->copy(node, successor);
211 augment->propagate(parent, successor);
212 }
213
214 successor->rb_left = tmp = node->rb_left;
215 rb_set_parent(tmp, successor);
216
217 pc = node->__rb_parent_color;
218 tmp = __rb_parent(pc);
219 __rb_change_child(node, successor, tmp, root);
220 if (child2) {
221 successor->__rb_parent_color = pc;
222 rb_set_parent_color(child2, parent, RB_BLACK);
223 rebalance = NULL;
224 } else {
225 unsigned long pc2 = successor->__rb_parent_color;
226 successor->__rb_parent_color = pc;
227 rebalance = __rb_is_black(pc2) ? parent : NULL;
228 }
229 tmp = successor;
230 }
231
232 augment->propagate(tmp, NULL);
233 return rebalance;
234 }
235
236 static __always_inline void
rb_erase_augmented(struct rb_node * node,struct rb_root * root,const struct rb_augment_callbacks * augment)237 rb_erase_augmented(struct rb_node *node, struct rb_root *root,
238 const struct rb_augment_callbacks *augment)
239 {
240 struct rb_node *rebalance = __rb_erase_augmented(node, root, augment);
241 if (rebalance)
242 __rb_erase_color(rebalance, root, augment->rotate);
243 }
244
245 #endif /* _TOOLS_LINUX_RBTREE_AUGMENTED_H */
246