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Commit | Line | Data |
---|---|---|
7ba890bf KP |
1 | /* |
2 | Red Black Trees | |
3 | (C) 1999 Andrea Arcangeli <andrea@suse.de> | |
4 | (C) 2002 David Woodhouse <dwmw2@infradead.org> | |
5 | ||
1a459660 | 6 | * SPDX-License-Identifier: GPL-2.0+ |
7ba890bf KP |
7 | |
8 | linux/lib/rbtree.c | |
9 | */ | |
10 | ||
11 | #include <ubi_uboot.h> | |
12 | #include <linux/rbtree.h> | |
13 | ||
14 | static void __rb_rotate_left(struct rb_node *node, struct rb_root *root) | |
15 | { | |
16 | struct rb_node *right = node->rb_right; | |
17 | struct rb_node *parent = rb_parent(node); | |
18 | ||
19 | if ((node->rb_right = right->rb_left)) | |
20 | rb_set_parent(right->rb_left, node); | |
21 | right->rb_left = node; | |
22 | ||
23 | rb_set_parent(right, parent); | |
24 | ||
25 | if (parent) | |
26 | { | |
27 | if (node == parent->rb_left) | |
28 | parent->rb_left = right; | |
29 | else | |
30 | parent->rb_right = right; | |
31 | } | |
32 | else | |
33 | root->rb_node = right; | |
34 | rb_set_parent(node, right); | |
35 | } | |
36 | ||
37 | static void __rb_rotate_right(struct rb_node *node, struct rb_root *root) | |
38 | { | |
39 | struct rb_node *left = node->rb_left; | |
40 | struct rb_node *parent = rb_parent(node); | |
41 | ||
42 | if ((node->rb_left = left->rb_right)) | |
43 | rb_set_parent(left->rb_right, node); | |
44 | left->rb_right = node; | |
45 | ||
46 | rb_set_parent(left, parent); | |
47 | ||
48 | if (parent) | |
49 | { | |
50 | if (node == parent->rb_right) | |
51 | parent->rb_right = left; | |
52 | else | |
53 | parent->rb_left = left; | |
54 | } | |
55 | else | |
56 | root->rb_node = left; | |
57 | rb_set_parent(node, left); | |
58 | } | |
59 | ||
60 | void rb_insert_color(struct rb_node *node, struct rb_root *root) | |
61 | { | |
62 | struct rb_node *parent, *gparent; | |
63 | ||
64 | while ((parent = rb_parent(node)) && rb_is_red(parent)) | |
65 | { | |
66 | gparent = rb_parent(parent); | |
67 | ||
68 | if (parent == gparent->rb_left) | |
69 | { | |
70 | { | |
71 | register struct rb_node *uncle = gparent->rb_right; | |
72 | if (uncle && rb_is_red(uncle)) | |
73 | { | |
74 | rb_set_black(uncle); | |
75 | rb_set_black(parent); | |
76 | rb_set_red(gparent); | |
77 | node = gparent; | |
78 | continue; | |
79 | } | |
80 | } | |
81 | ||
82 | if (parent->rb_right == node) | |
83 | { | |
84 | register struct rb_node *tmp; | |
85 | __rb_rotate_left(parent, root); | |
86 | tmp = parent; | |
87 | parent = node; | |
88 | node = tmp; | |
89 | } | |
90 | ||
91 | rb_set_black(parent); | |
92 | rb_set_red(gparent); | |
93 | __rb_rotate_right(gparent, root); | |
94 | } else { | |
95 | { | |
96 | register struct rb_node *uncle = gparent->rb_left; | |
97 | if (uncle && rb_is_red(uncle)) | |
98 | { | |
99 | rb_set_black(uncle); | |
100 | rb_set_black(parent); | |
101 | rb_set_red(gparent); | |
102 | node = gparent; | |
103 | continue; | |
104 | } | |
105 | } | |
106 | ||
107 | if (parent->rb_left == node) | |
108 | { | |
109 | register struct rb_node *tmp; | |
110 | __rb_rotate_right(parent, root); | |
111 | tmp = parent; | |
112 | parent = node; | |
113 | node = tmp; | |
114 | } | |
115 | ||
116 | rb_set_black(parent); | |
117 | rb_set_red(gparent); | |
118 | __rb_rotate_left(gparent, root); | |
119 | } | |
120 | } | |
121 | ||
122 | rb_set_black(root->rb_node); | |
123 | } | |
124 | ||
125 | static void __rb_erase_color(struct rb_node *node, struct rb_node *parent, | |
126 | struct rb_root *root) | |
127 | { | |
128 | struct rb_node *other; | |
129 | ||
130 | while ((!node || rb_is_black(node)) && node != root->rb_node) | |
131 | { | |
132 | if (parent->rb_left == node) | |
133 | { | |
134 | other = parent->rb_right; | |
135 | if (rb_is_red(other)) | |
136 | { | |
137 | rb_set_black(other); | |
138 | rb_set_red(parent); | |
139 | __rb_rotate_left(parent, root); | |
140 | other = parent->rb_right; | |
141 | } | |
142 | if ((!other->rb_left || rb_is_black(other->rb_left)) && | |
143 | (!other->rb_right || rb_is_black(other->rb_right))) | |
144 | { | |
145 | rb_set_red(other); | |
146 | node = parent; | |
147 | parent = rb_parent(node); | |
148 | } | |
149 | else | |
150 | { | |
151 | if (!other->rb_right || rb_is_black(other->rb_right)) | |
152 | { | |
153 | struct rb_node *o_left; | |
154 | if ((o_left = other->rb_left)) | |
155 | rb_set_black(o_left); | |
156 | rb_set_red(other); | |
157 | __rb_rotate_right(other, root); | |
158 | other = parent->rb_right; | |
159 | } | |
160 | rb_set_color(other, rb_color(parent)); | |
161 | rb_set_black(parent); | |
162 | if (other->rb_right) | |
163 | rb_set_black(other->rb_right); | |
164 | __rb_rotate_left(parent, root); | |
165 | node = root->rb_node; | |
166 | break; | |
167 | } | |
168 | } | |
169 | else | |
170 | { | |
171 | other = parent->rb_left; | |
172 | if (rb_is_red(other)) | |
173 | { | |
174 | rb_set_black(other); | |
175 | rb_set_red(parent); | |
176 | __rb_rotate_right(parent, root); | |
177 | other = parent->rb_left; | |
178 | } | |
179 | if ((!other->rb_left || rb_is_black(other->rb_left)) && | |
180 | (!other->rb_right || rb_is_black(other->rb_right))) | |
181 | { | |
182 | rb_set_red(other); | |
183 | node = parent; | |
184 | parent = rb_parent(node); | |
185 | } | |
186 | else | |
187 | { | |
188 | if (!other->rb_left || rb_is_black(other->rb_left)) | |
189 | { | |
190 | register struct rb_node *o_right; | |
191 | if ((o_right = other->rb_right)) | |
192 | rb_set_black(o_right); | |
193 | rb_set_red(other); | |
194 | __rb_rotate_left(other, root); | |
195 | other = parent->rb_left; | |
196 | } | |
197 | rb_set_color(other, rb_color(parent)); | |
198 | rb_set_black(parent); | |
199 | if (other->rb_left) | |
200 | rb_set_black(other->rb_left); | |
201 | __rb_rotate_right(parent, root); | |
202 | node = root->rb_node; | |
203 | break; | |
204 | } | |
205 | } | |
206 | } | |
207 | if (node) | |
208 | rb_set_black(node); | |
209 | } | |
210 | ||
211 | void rb_erase(struct rb_node *node, struct rb_root *root) | |
212 | { | |
213 | struct rb_node *child, *parent; | |
214 | int color; | |
215 | ||
216 | if (!node->rb_left) | |
217 | child = node->rb_right; | |
218 | else if (!node->rb_right) | |
219 | child = node->rb_left; | |
220 | else | |
221 | { | |
222 | struct rb_node *old = node, *left; | |
223 | ||
224 | node = node->rb_right; | |
225 | while ((left = node->rb_left) != NULL) | |
226 | node = left; | |
227 | child = node->rb_right; | |
228 | parent = rb_parent(node); | |
229 | color = rb_color(node); | |
230 | ||
231 | if (child) | |
232 | rb_set_parent(child, parent); | |
233 | if (parent == old) { | |
234 | parent->rb_right = child; | |
235 | parent = node; | |
236 | } else | |
237 | parent->rb_left = child; | |
238 | ||
239 | node->rb_parent_color = old->rb_parent_color; | |
240 | node->rb_right = old->rb_right; | |
241 | node->rb_left = old->rb_left; | |
242 | ||
243 | if (rb_parent(old)) | |
244 | { | |
245 | if (rb_parent(old)->rb_left == old) | |
246 | rb_parent(old)->rb_left = node; | |
247 | else | |
248 | rb_parent(old)->rb_right = node; | |
249 | } else | |
250 | root->rb_node = node; | |
251 | ||
252 | rb_set_parent(old->rb_left, node); | |
253 | if (old->rb_right) | |
254 | rb_set_parent(old->rb_right, node); | |
255 | goto color; | |
256 | } | |
257 | ||
258 | parent = rb_parent(node); | |
259 | color = rb_color(node); | |
260 | ||
261 | if (child) | |
262 | rb_set_parent(child, parent); | |
263 | if (parent) | |
264 | { | |
265 | if (parent->rb_left == node) | |
266 | parent->rb_left = child; | |
267 | else | |
268 | parent->rb_right = child; | |
269 | } | |
270 | else | |
271 | root->rb_node = child; | |
272 | ||
273 | color: | |
274 | if (color == RB_BLACK) | |
275 | __rb_erase_color(child, parent, root); | |
276 | } | |
277 | ||
278 | /* | |
279 | * This function returns the first node (in sort order) of the tree. | |
280 | */ | |
281 | struct rb_node *rb_first(struct rb_root *root) | |
282 | { | |
283 | struct rb_node *n; | |
284 | ||
285 | n = root->rb_node; | |
286 | if (!n) | |
287 | return NULL; | |
288 | while (n->rb_left) | |
289 | n = n->rb_left; | |
290 | return n; | |
291 | } | |
292 | ||
293 | struct rb_node *rb_last(struct rb_root *root) | |
294 | { | |
295 | struct rb_node *n; | |
296 | ||
297 | n = root->rb_node; | |
298 | if (!n) | |
299 | return NULL; | |
300 | while (n->rb_right) | |
301 | n = n->rb_right; | |
302 | return n; | |
303 | } | |
304 | ||
305 | struct rb_node *rb_next(struct rb_node *node) | |
306 | { | |
307 | struct rb_node *parent; | |
308 | ||
309 | if (rb_parent(node) == node) | |
310 | return NULL; | |
311 | ||
312 | /* If we have a right-hand child, go down and then left as far | |
313 | as we can. */ | |
314 | if (node->rb_right) { | |
315 | node = node->rb_right; | |
316 | while (node->rb_left) | |
317 | node=node->rb_left; | |
318 | return node; | |
319 | } | |
320 | ||
321 | /* No right-hand children. Everything down and left is | |
322 | smaller than us, so any 'next' node must be in the general | |
323 | direction of our parent. Go up the tree; any time the | |
324 | ancestor is a right-hand child of its parent, keep going | |
325 | up. First time it's a left-hand child of its parent, said | |
326 | parent is our 'next' node. */ | |
327 | while ((parent = rb_parent(node)) && node == parent->rb_right) | |
328 | node = parent; | |
329 | ||
330 | return parent; | |
331 | } | |
332 | ||
333 | struct rb_node *rb_prev(struct rb_node *node) | |
334 | { | |
335 | struct rb_node *parent; | |
336 | ||
337 | if (rb_parent(node) == node) | |
338 | return NULL; | |
339 | ||
340 | /* If we have a left-hand child, go down and then right as far | |
341 | as we can. */ | |
342 | if (node->rb_left) { | |
343 | node = node->rb_left; | |
344 | while (node->rb_right) | |
345 | node=node->rb_right; | |
346 | return node; | |
347 | } | |
348 | ||
349 | /* No left-hand children. Go up till we find an ancestor which | |
350 | is a right-hand child of its parent */ | |
351 | while ((parent = rb_parent(node)) && node == parent->rb_left) | |
352 | node = parent; | |
353 | ||
354 | return parent; | |
355 | } | |
356 | ||
357 | void rb_replace_node(struct rb_node *victim, struct rb_node *new, | |
358 | struct rb_root *root) | |
359 | { | |
360 | struct rb_node *parent = rb_parent(victim); | |
361 | ||
362 | /* Set the surrounding nodes to point to the replacement */ | |
363 | if (parent) { | |
364 | if (victim == parent->rb_left) | |
365 | parent->rb_left = new; | |
366 | else | |
367 | parent->rb_right = new; | |
368 | } else { | |
369 | root->rb_node = new; | |
370 | } | |
371 | if (victim->rb_left) | |
372 | rb_set_parent(victim->rb_left, new); | |
373 | if (victim->rb_right) | |
374 | rb_set_parent(victim->rb_right, new); | |
375 | ||
376 | /* Copy the pointers/colour from the victim to the replacement */ | |
377 | *new = *victim; | |
378 | } |