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1 | // SPDX-License-Identifier: ISC AND BSD-2-Clause | |
2 | /* RB-tree */ | |
3 | ||
4 | /* | |
5 | * Copyright 2002 Niels Provos <provos@citi.umich.edu> | |
6 | */ | |
7 | ||
8 | /* | |
9 | * Copyright (c) 2016 David Gwynne <dlg@openbsd.org> | |
10 | */ | |
11 | ||
12 | #ifdef HAVE_CONFIG_H | |
13 | #include "config.h" | |
14 | #endif | |
15 | ||
16 | #include <string.h> | |
17 | #include "typerb.h" | |
18 | ||
19 | #define RB_BLACK 0 | |
20 | #define RB_RED 1 | |
21 | ||
22 | #define rb_entry typed_rb_entry | |
23 | #define rbt_tree typed_rb_root | |
24 | ||
25 | #define RBE_LEFT(_rbe) (_rbe)->rbt_left | |
26 | #define RBE_RIGHT(_rbe) (_rbe)->rbt_right | |
27 | #define RBE_PARENT(_rbe) (_rbe)->rbt_parent | |
28 | #define RBE_COLOR(_rbe) (_rbe)->rbt_color | |
29 | ||
30 | #define RBH_ROOT(_rbt) (_rbt)->rbt_root | |
31 | ||
32 | static inline void rbe_set(struct rb_entry *rbe, struct rb_entry *parent) | |
33 | { | |
34 | RBE_PARENT(rbe) = parent; | |
35 | RBE_LEFT(rbe) = RBE_RIGHT(rbe) = NULL; | |
36 | RBE_COLOR(rbe) = RB_RED; | |
37 | } | |
38 | ||
39 | static inline void rbe_set_blackred(struct rb_entry *black, | |
40 | struct rb_entry *red) | |
41 | { | |
42 | RBE_COLOR(black) = RB_BLACK; | |
43 | RBE_COLOR(red) = RB_RED; | |
44 | } | |
45 | ||
46 | static inline void rbe_rotate_left(struct rbt_tree *rbt, struct rb_entry *rbe) | |
47 | { | |
48 | struct rb_entry *parent; | |
49 | struct rb_entry *tmp; | |
50 | ||
51 | tmp = RBE_RIGHT(rbe); | |
52 | RBE_RIGHT(rbe) = RBE_LEFT(tmp); | |
53 | if (RBE_RIGHT(rbe) != NULL) | |
54 | RBE_PARENT(RBE_LEFT(tmp)) = rbe; | |
55 | ||
56 | parent = RBE_PARENT(rbe); | |
57 | RBE_PARENT(tmp) = parent; | |
58 | if (parent != NULL) { | |
59 | if (rbe == RBE_LEFT(parent)) | |
60 | RBE_LEFT(parent) = tmp; | |
61 | else | |
62 | RBE_RIGHT(parent) = tmp; | |
63 | } else | |
64 | RBH_ROOT(rbt) = tmp; | |
65 | ||
66 | RBE_LEFT(tmp) = rbe; | |
67 | RBE_PARENT(rbe) = tmp; | |
68 | } | |
69 | ||
70 | static inline void rbe_rotate_right(struct rbt_tree *rbt, struct rb_entry *rbe) | |
71 | { | |
72 | struct rb_entry *parent; | |
73 | struct rb_entry *tmp; | |
74 | ||
75 | tmp = RBE_LEFT(rbe); | |
76 | RBE_LEFT(rbe) = RBE_RIGHT(tmp); | |
77 | if (RBE_LEFT(rbe) != NULL) | |
78 | RBE_PARENT(RBE_RIGHT(tmp)) = rbe; | |
79 | ||
80 | parent = RBE_PARENT(rbe); | |
81 | RBE_PARENT(tmp) = parent; | |
82 | if (parent != NULL) { | |
83 | if (rbe == RBE_LEFT(parent)) | |
84 | RBE_LEFT(parent) = tmp; | |
85 | else | |
86 | RBE_RIGHT(parent) = tmp; | |
87 | } else | |
88 | RBH_ROOT(rbt) = tmp; | |
89 | ||
90 | RBE_RIGHT(tmp) = rbe; | |
91 | RBE_PARENT(rbe) = tmp; | |
92 | } | |
93 | ||
94 | static inline void rbe_insert_color(struct rbt_tree *rbt, struct rb_entry *rbe) | |
95 | { | |
96 | struct rb_entry *parent, *gparent, *tmp; | |
97 | ||
98 | rbt->count++; | |
99 | ||
100 | while ((parent = RBE_PARENT(rbe)) != NULL | |
101 | && RBE_COLOR(parent) == RB_RED) { | |
102 | gparent = RBE_PARENT(parent); | |
103 | ||
104 | if (parent == RBE_LEFT(gparent)) { | |
105 | tmp = RBE_RIGHT(gparent); | |
106 | if (tmp != NULL && RBE_COLOR(tmp) == RB_RED) { | |
107 | RBE_COLOR(tmp) = RB_BLACK; | |
108 | rbe_set_blackred(parent, gparent); | |
109 | rbe = gparent; | |
110 | continue; | |
111 | } | |
112 | ||
113 | if (RBE_RIGHT(parent) == rbe) { | |
114 | rbe_rotate_left(rbt, parent); | |
115 | tmp = parent; | |
116 | parent = rbe; | |
117 | rbe = tmp; | |
118 | } | |
119 | ||
120 | rbe_set_blackred(parent, gparent); | |
121 | rbe_rotate_right(rbt, gparent); | |
122 | } else { | |
123 | tmp = RBE_LEFT(gparent); | |
124 | if (tmp != NULL && RBE_COLOR(tmp) == RB_RED) { | |
125 | RBE_COLOR(tmp) = RB_BLACK; | |
126 | rbe_set_blackred(parent, gparent); | |
127 | rbe = gparent; | |
128 | continue; | |
129 | } | |
130 | ||
131 | if (RBE_LEFT(parent) == rbe) { | |
132 | rbe_rotate_right(rbt, parent); | |
133 | tmp = parent; | |
134 | parent = rbe; | |
135 | rbe = tmp; | |
136 | } | |
137 | ||
138 | rbe_set_blackred(parent, gparent); | |
139 | rbe_rotate_left(rbt, gparent); | |
140 | } | |
141 | } | |
142 | ||
143 | RBE_COLOR(RBH_ROOT(rbt)) = RB_BLACK; | |
144 | } | |
145 | ||
146 | static inline void rbe_remove_color(struct rbt_tree *rbt, | |
147 | struct rb_entry *parent, | |
148 | struct rb_entry *rbe) | |
149 | { | |
150 | struct rb_entry *tmp; | |
151 | ||
152 | while ((rbe == NULL || RBE_COLOR(rbe) == RB_BLACK) | |
153 | && rbe != RBH_ROOT(rbt) && parent) { | |
154 | if (RBE_LEFT(parent) == rbe) { | |
155 | tmp = RBE_RIGHT(parent); | |
156 | if (RBE_COLOR(tmp) == RB_RED) { | |
157 | rbe_set_blackred(tmp, parent); | |
158 | rbe_rotate_left(rbt, parent); | |
159 | tmp = RBE_RIGHT(parent); | |
160 | } | |
161 | if ((RBE_LEFT(tmp) == NULL | |
162 | || RBE_COLOR(RBE_LEFT(tmp)) == RB_BLACK) | |
163 | && (RBE_RIGHT(tmp) == NULL | |
164 | || RBE_COLOR(RBE_RIGHT(tmp)) == RB_BLACK)) { | |
165 | RBE_COLOR(tmp) = RB_RED; | |
166 | rbe = parent; | |
167 | parent = RBE_PARENT(rbe); | |
168 | } else { | |
169 | if (RBE_RIGHT(tmp) == NULL | |
170 | || RBE_COLOR(RBE_RIGHT(tmp)) == RB_BLACK) { | |
171 | struct rb_entry *oleft; | |
172 | ||
173 | oleft = RBE_LEFT(tmp); | |
174 | if (oleft != NULL) | |
175 | RBE_COLOR(oleft) = RB_BLACK; | |
176 | ||
177 | RBE_COLOR(tmp) = RB_RED; | |
178 | rbe_rotate_right(rbt, tmp); | |
179 | tmp = RBE_RIGHT(parent); | |
180 | } | |
181 | ||
182 | RBE_COLOR(tmp) = RBE_COLOR(parent); | |
183 | RBE_COLOR(parent) = RB_BLACK; | |
184 | if (RBE_RIGHT(tmp)) | |
185 | RBE_COLOR(RBE_RIGHT(tmp)) = RB_BLACK; | |
186 | ||
187 | rbe_rotate_left(rbt, parent); | |
188 | rbe = RBH_ROOT(rbt); | |
189 | break; | |
190 | } | |
191 | } else { | |
192 | tmp = RBE_LEFT(parent); | |
193 | if (RBE_COLOR(tmp) == RB_RED) { | |
194 | rbe_set_blackred(tmp, parent); | |
195 | rbe_rotate_right(rbt, parent); | |
196 | tmp = RBE_LEFT(parent); | |
197 | } | |
198 | ||
199 | if ((RBE_LEFT(tmp) == NULL | |
200 | || RBE_COLOR(RBE_LEFT(tmp)) == RB_BLACK) | |
201 | && (RBE_RIGHT(tmp) == NULL | |
202 | || RBE_COLOR(RBE_RIGHT(tmp)) == RB_BLACK)) { | |
203 | RBE_COLOR(tmp) = RB_RED; | |
204 | rbe = parent; | |
205 | parent = RBE_PARENT(rbe); | |
206 | } else { | |
207 | if (RBE_LEFT(tmp) == NULL | |
208 | || RBE_COLOR(RBE_LEFT(tmp)) == RB_BLACK) { | |
209 | struct rb_entry *oright; | |
210 | ||
211 | oright = RBE_RIGHT(tmp); | |
212 | if (oright != NULL) | |
213 | RBE_COLOR(oright) = RB_BLACK; | |
214 | ||
215 | RBE_COLOR(tmp) = RB_RED; | |
216 | rbe_rotate_left(rbt, tmp); | |
217 | tmp = RBE_LEFT(parent); | |
218 | } | |
219 | ||
220 | RBE_COLOR(tmp) = RBE_COLOR(parent); | |
221 | RBE_COLOR(parent) = RB_BLACK; | |
222 | if (RBE_LEFT(tmp) != NULL) | |
223 | RBE_COLOR(RBE_LEFT(tmp)) = RB_BLACK; | |
224 | ||
225 | rbe_rotate_right(rbt, parent); | |
226 | rbe = RBH_ROOT(rbt); | |
227 | break; | |
228 | } | |
229 | } | |
230 | } | |
231 | ||
232 | if (rbe != NULL) | |
233 | RBE_COLOR(rbe) = RB_BLACK; | |
234 | } | |
235 | ||
236 | static inline struct rb_entry * | |
237 | rbe_remove(struct rbt_tree *rbt, struct rb_entry *rbe) | |
238 | { | |
239 | struct rb_entry *child, *parent, *old = rbe; | |
240 | unsigned int color; | |
241 | ||
242 | if (RBE_LEFT(rbe) == NULL) | |
243 | child = RBE_RIGHT(rbe); | |
244 | else if (RBE_RIGHT(rbe) == NULL) | |
245 | child = RBE_LEFT(rbe); | |
246 | else { | |
247 | struct rb_entry *tmp; | |
248 | ||
249 | rbe = RBE_RIGHT(rbe); | |
250 | while ((tmp = RBE_LEFT(rbe)) != NULL) | |
251 | rbe = tmp; | |
252 | ||
253 | child = RBE_RIGHT(rbe); | |
254 | parent = RBE_PARENT(rbe); | |
255 | color = RBE_COLOR(rbe); | |
256 | if (child != NULL) | |
257 | RBE_PARENT(child) = parent; | |
258 | if (parent != NULL) { | |
259 | if (RBE_LEFT(parent) == rbe) | |
260 | RBE_LEFT(parent) = child; | |
261 | else | |
262 | RBE_RIGHT(parent) = child; | |
263 | } else | |
264 | RBH_ROOT(rbt) = child; | |
265 | if (RBE_PARENT(rbe) == old) | |
266 | parent = rbe; | |
267 | *rbe = *old; | |
268 | ||
269 | tmp = RBE_PARENT(old); | |
270 | if (tmp != NULL) { | |
271 | if (RBE_LEFT(tmp) == old) | |
272 | RBE_LEFT(tmp) = rbe; | |
273 | else | |
274 | RBE_RIGHT(tmp) = rbe; | |
275 | } else | |
276 | RBH_ROOT(rbt) = rbe; | |
277 | ||
278 | RBE_PARENT(RBE_LEFT(old)) = rbe; | |
279 | if (RBE_RIGHT(old)) | |
280 | RBE_PARENT(RBE_RIGHT(old)) = rbe; | |
281 | ||
282 | goto color; | |
283 | } | |
284 | ||
285 | parent = RBE_PARENT(rbe); | |
286 | color = RBE_COLOR(rbe); | |
287 | ||
288 | if (child != NULL) | |
289 | RBE_PARENT(child) = parent; | |
290 | if (parent != NULL) { | |
291 | if (RBE_LEFT(parent) == rbe) | |
292 | RBE_LEFT(parent) = child; | |
293 | else | |
294 | RBE_RIGHT(parent) = child; | |
295 | } else | |
296 | RBH_ROOT(rbt) = child; | |
297 | color: | |
298 | if (color == RB_BLACK) | |
299 | rbe_remove_color(rbt, parent, child); | |
300 | ||
301 | rbt->count--; | |
302 | memset(old, 0, sizeof(*old)); | |
303 | return (old); | |
304 | } | |
305 | ||
306 | struct typed_rb_entry *typed_rb_remove(struct rbt_tree *rbt, | |
307 | struct rb_entry *rbe) | |
308 | { | |
309 | return rbe_remove(rbt, rbe); | |
310 | } | |
311 | ||
312 | struct typed_rb_entry *typed_rb_insert(struct rbt_tree *rbt, | |
313 | struct rb_entry *rbe, int (*cmpfn)( | |
314 | const struct typed_rb_entry *a, | |
315 | const struct typed_rb_entry *b)) | |
316 | { | |
317 | struct rb_entry *tmp; | |
318 | struct rb_entry *parent = NULL; | |
319 | int comp = 0; | |
320 | ||
321 | tmp = RBH_ROOT(rbt); | |
322 | while (tmp != NULL) { | |
323 | parent = tmp; | |
324 | ||
325 | comp = cmpfn(rbe, tmp); | |
326 | if (comp < 0) | |
327 | tmp = RBE_LEFT(tmp); | |
328 | else if (comp > 0) | |
329 | tmp = RBE_RIGHT(tmp); | |
330 | else | |
331 | return tmp; | |
332 | } | |
333 | ||
334 | rbe_set(rbe, parent); | |
335 | ||
336 | if (parent != NULL) { | |
337 | if (comp < 0) | |
338 | RBE_LEFT(parent) = rbe; | |
339 | else | |
340 | RBE_RIGHT(parent) = rbe; | |
341 | } else | |
342 | RBH_ROOT(rbt) = rbe; | |
343 | ||
344 | rbe_insert_color(rbt, rbe); | |
345 | ||
346 | return NULL; | |
347 | } | |
348 | ||
349 | /* Finds the node with the same key as elm */ | |
350 | const struct rb_entry *typed_rb_find(const struct rbt_tree *rbt, | |
351 | const struct rb_entry *key, | |
352 | int (*cmpfn)( | |
353 | const struct typed_rb_entry *a, | |
354 | const struct typed_rb_entry *b)) | |
355 | { | |
356 | const struct rb_entry *tmp = RBH_ROOT(rbt); | |
357 | int comp; | |
358 | ||
359 | while (tmp != NULL) { | |
360 | comp = cmpfn(key, tmp); | |
361 | if (comp < 0) | |
362 | tmp = RBE_LEFT(tmp); | |
363 | else if (comp > 0) | |
364 | tmp = RBE_RIGHT(tmp); | |
365 | else | |
366 | return tmp; | |
367 | } | |
368 | ||
369 | return NULL; | |
370 | } | |
371 | ||
372 | const struct rb_entry *typed_rb_find_gteq(const struct rbt_tree *rbt, | |
373 | const struct rb_entry *key, | |
374 | int (*cmpfn)( | |
375 | const struct typed_rb_entry *a, | |
376 | const struct typed_rb_entry *b)) | |
377 | { | |
378 | const struct rb_entry *tmp = RBH_ROOT(rbt), *best = NULL; | |
379 | int comp; | |
380 | ||
381 | while (tmp != NULL) { | |
382 | comp = cmpfn(key, tmp); | |
383 | if (comp < 0) { | |
384 | best = tmp; | |
385 | tmp = RBE_LEFT(tmp); | |
386 | } else if (comp > 0) | |
387 | tmp = RBE_RIGHT(tmp); | |
388 | else | |
389 | return tmp; | |
390 | } | |
391 | ||
392 | return best; | |
393 | } | |
394 | ||
395 | const struct rb_entry *typed_rb_find_lt(const struct rbt_tree *rbt, | |
396 | const struct rb_entry *key, | |
397 | int (*cmpfn)( | |
398 | const struct typed_rb_entry *a, | |
399 | const struct typed_rb_entry *b)) | |
400 | { | |
401 | const struct rb_entry *tmp = RBH_ROOT(rbt), *best = NULL; | |
402 | int comp; | |
403 | ||
404 | while (tmp != NULL) { | |
405 | comp = cmpfn(key, tmp); | |
406 | if (comp <= 0) | |
407 | tmp = RBE_LEFT(tmp); | |
408 | else { | |
409 | best = tmp; | |
410 | tmp = RBE_RIGHT(tmp); | |
411 | } | |
412 | } | |
413 | ||
414 | return best; | |
415 | } | |
416 | ||
417 | struct rb_entry *typed_rb_next(const struct rb_entry *rbe_const) | |
418 | { | |
419 | struct rb_entry *rbe = (struct rb_entry *)rbe_const; | |
420 | ||
421 | if (RBE_RIGHT(rbe) != NULL) { | |
422 | rbe = RBE_RIGHT(rbe); | |
423 | while (RBE_LEFT(rbe) != NULL) | |
424 | rbe = RBE_LEFT(rbe); | |
425 | } else { | |
426 | if (RBE_PARENT(rbe) && (rbe == RBE_LEFT(RBE_PARENT(rbe)))) | |
427 | rbe = RBE_PARENT(rbe); | |
428 | else { | |
429 | while (RBE_PARENT(rbe) | |
430 | && (rbe == RBE_RIGHT(RBE_PARENT(rbe)))) | |
431 | rbe = RBE_PARENT(rbe); | |
432 | rbe = RBE_PARENT(rbe); | |
433 | } | |
434 | } | |
435 | ||
436 | return rbe; | |
437 | } | |
438 | ||
439 | struct rb_entry *typed_rb_prev(const struct rb_entry *rbe_const) | |
440 | { | |
441 | struct rb_entry *rbe = (struct rb_entry *)rbe_const; | |
442 | ||
443 | if (RBE_LEFT(rbe)) { | |
444 | rbe = RBE_LEFT(rbe); | |
445 | while (RBE_RIGHT(rbe)) | |
446 | rbe = RBE_RIGHT(rbe); | |
447 | } else { | |
448 | if (RBE_PARENT(rbe) && (rbe == RBE_RIGHT(RBE_PARENT(rbe)))) | |
449 | rbe = RBE_PARENT(rbe); | |
450 | else { | |
451 | while (RBE_PARENT(rbe) | |
452 | && (rbe == RBE_LEFT(RBE_PARENT(rbe)))) | |
453 | rbe = RBE_PARENT(rbe); | |
454 | rbe = RBE_PARENT(rbe); | |
455 | } | |
456 | } | |
457 | ||
458 | return rbe; | |
459 | } | |
460 | ||
461 | struct rb_entry *typed_rb_min(const struct rbt_tree *rbt) | |
462 | { | |
463 | struct rb_entry *rbe = RBH_ROOT(rbt); | |
464 | struct rb_entry *parent = NULL; | |
465 | ||
466 | while (rbe != NULL) { | |
467 | parent = rbe; | |
468 | rbe = RBE_LEFT(rbe); | |
469 | } | |
470 | ||
471 | return parent; | |
472 | } | |
473 | ||
474 | struct rb_entry *typed_rb_max(const struct rbt_tree *rbt) | |
475 | { | |
476 | struct rb_entry *rbe = RBH_ROOT(rbt); | |
477 | struct rb_entry *parent = NULL; | |
478 | ||
479 | while (rbe != NULL) { | |
480 | parent = rbe; | |
481 | rbe = RBE_RIGHT(rbe); | |
482 | } | |
483 | ||
484 | return parent; | |
485 | } | |
486 | ||
487 | bool typed_rb_member(const struct typed_rb_root *rbt, | |
488 | const struct typed_rb_entry *rbe) | |
489 | { | |
490 | while (rbe->rbt_parent) | |
491 | rbe = rbe->rbt_parent; | |
492 | return rbe == rbt->rbt_root; | |
493 | } |