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959ef981 | 1 | // SPDX-License-Identifier: GPL-2.0 |
da23017d NS |
2 | /* |
3 | * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc. | |
4 | * All Rights Reserved. | |
da23017d | 5 | */ |
2bd0ea18 | 6 | |
6b803e5a | 7 | #include "libxfs.h" |
2bd0ea18 NS |
8 | #include "avl.h" |
9 | ||
10 | #define CERT ASSERT | |
11 | ||
12 | #ifdef AVL_DEBUG | |
13 | ||
14 | static void | |
15 | avl_checknode( | |
0c2a7d46 CH |
16 | avltree_desc_t *tree, |
17 | avlnode_t *np) | |
2bd0ea18 | 18 | { |
0c2a7d46 CH |
19 | avlnode_t *back = np->avl_back; |
20 | avlnode_t *forw = np->avl_forw; | |
21 | avlnode_t *nextino = np->avl_nextino; | |
22 | int bal = np->avl_balance; | |
2bd0ea18 NS |
23 | |
24 | ASSERT(bal != AVL_BALANCE || (!back && !forw) || (back && forw)); | |
25 | ASSERT(bal != AVL_FORW || forw); | |
26 | ASSERT(bal != AVL_BACK || back); | |
27 | ||
28 | if (forw) { | |
29 | ASSERT(AVL_START(tree, np) < AVL_START(tree, forw)); | |
30 | ASSERT(np->avl_forw->avl_parent == np); | |
31 | ASSERT(back || bal == AVL_FORW); | |
32 | } else { | |
33 | ASSERT(bal != AVL_FORW); | |
34 | ASSERT(bal == AVL_BALANCE || back); | |
35 | ASSERT(bal == AVL_BACK || !back); | |
36 | } | |
37 | ||
38 | if (back) { | |
39 | ASSERT(AVL_START(tree, np) > AVL_START(tree, back)); | |
40 | ASSERT(np->avl_back->avl_parent == np); | |
41 | ASSERT(forw || bal == AVL_BACK); | |
42 | } else { | |
43 | ASSERT(bal != AVL_BACK); | |
44 | ASSERT(bal == AVL_BALANCE || forw); | |
45 | ASSERT(bal == AVL_FORW || !forw); | |
46 | } | |
47 | ||
48 | if (nextino == NULL) | |
49 | ASSERT(forw == NULL); | |
50 | else | |
51 | ASSERT(AVL_END(tree, np) <= AVL_START(tree, nextino)); | |
52 | } | |
53 | ||
54 | static void | |
55 | avl_checktree( | |
0c2a7d46 CH |
56 | avltree_desc_t *tree, |
57 | avlnode_t *root) | |
2bd0ea18 | 58 | { |
0c2a7d46 | 59 | avlnode_t *nlast, *nnext, *np; |
ee6cd73e CH |
60 | uintptr_t offset = 0; |
61 | uintptr_t end; | |
2bd0ea18 NS |
62 | |
63 | nlast = nnext = root; | |
64 | ||
65 | ASSERT(!nnext || nnext->avl_parent == NULL); | |
66 | ||
67 | while (nnext) { | |
68 | ||
69 | avl_checknode(tree, nnext); | |
70 | end = AVL_END(tree, nnext); | |
71 | ||
72 | if (end <= offset) { | |
73 | if ((np = nnext->avl_forw) && np != nlast) { | |
74 | nlast = nnext; | |
75 | nnext = np; | |
76 | } else { | |
77 | nlast = nnext; | |
78 | nnext = nnext->avl_parent; | |
79 | } | |
80 | continue; | |
81 | } | |
82 | ||
83 | nlast = nnext; | |
84 | if (np = nnext->avl_back) { | |
85 | if (AVL_END(tree, np) > offset) { | |
86 | nnext = np; | |
87 | continue; | |
88 | } | |
89 | } | |
90 | ||
91 | np = nnext; | |
92 | nnext = nnext->avl_forw; | |
93 | if (!nnext) | |
94 | nnext = np->avl_parent; | |
95 | ||
96 | offset = end; | |
97 | } | |
98 | } | |
99 | #else /* ! AVL_DEBUG */ | |
100 | #define avl_checktree(t,x) | |
101 | #endif /* AVL_DEBUG */ | |
102 | ||
103 | ||
104 | /* | |
105 | * Reset balance for np up through tree. | |
106 | * ``direction'' is the way that np's balance | |
107 | * is headed after the deletion of one of its children -- | |
108 | * e.g., deleting a avl_forw child sends avl_balance toward AVL_BACK. | |
109 | * Called only when deleting a node from the tree. | |
110 | */ | |
111 | static void | |
112 | retreat( | |
113 | avltree_desc_t *tree, | |
0c2a7d46 CH |
114 | avlnode_t *np, |
115 | int direction) | |
2bd0ea18 | 116 | { |
0c2a7d46 CH |
117 | avlnode_t **rootp = &tree->avl_root; |
118 | avlnode_t *parent; | |
119 | avlnode_t *child; | |
120 | avlnode_t *tmp; | |
121 | int bal; | |
2bd0ea18 NS |
122 | |
123 | do { | |
124 | ASSERT(direction == AVL_BACK || direction == AVL_FORW); | |
125 | ||
126 | if (np->avl_balance == AVL_BALANCE) { | |
127 | np->avl_balance = direction; | |
128 | return; | |
129 | } | |
130 | ||
131 | parent = np->avl_parent; | |
132 | ||
133 | /* | |
134 | * If balance is being restored, no local node | |
135 | * reorganization is necessary, but may be at | |
136 | * a higher node. Reset direction and continue. | |
137 | */ | |
138 | if (direction != np->avl_balance) { | |
139 | np->avl_balance = AVL_BALANCE; | |
140 | if (parent) { | |
141 | if (parent->avl_forw == np) | |
142 | direction = AVL_BACK; | |
143 | else | |
144 | direction = AVL_FORW; | |
145 | ||
146 | np = parent; | |
147 | continue; | |
148 | } | |
149 | return; | |
150 | } | |
151 | ||
152 | /* | |
153 | * Imbalance. If a avl_forw node was removed, direction | |
154 | * (and, by reduction, np->avl_balance) is/was AVL_BACK. | |
155 | */ | |
156 | if (np->avl_balance == AVL_BACK) { | |
157 | ||
158 | ASSERT(direction == AVL_BACK); | |
159 | child = np->avl_back; | |
160 | bal = child->avl_balance; | |
161 | ||
162 | if (bal != AVL_FORW) /* single LL */ { | |
163 | /* | |
164 | * np gets pushed down to lesser child's | |
165 | * avl_forw branch. | |
166 | * | |
dfc130f3 | 167 | * np-> -D +B |
2bd0ea18 NS |
168 | * / \ / \ |
169 | * child-> B deleted A -D | |
170 | * / \ / | |
171 | * A C C | |
172 | */ | |
173 | #ifdef AVL_PRINT | |
174 | if (!(tree->avl_flags & AVLF_DUPLICITY)) | |
175 | cmn_err(CE_CONT, "!LL delete b 0x%x c 0x%x\n", | |
176 | np, child); | |
177 | #endif | |
178 | np->avl_back = child->avl_forw; | |
179 | if (child->avl_forw) | |
180 | child->avl_forw->avl_parent = np; | |
181 | child->avl_forw = np; | |
182 | ||
183 | if (parent) { | |
184 | if (parent->avl_forw == np) { | |
185 | parent->avl_forw = child; | |
186 | direction = AVL_BACK; | |
187 | } else { | |
188 | ASSERT(parent->avl_back == np); | |
189 | parent->avl_back = child; | |
190 | direction = AVL_FORW; | |
191 | } | |
192 | } else { | |
193 | ASSERT(*rootp == np); | |
194 | *rootp = child; | |
195 | } | |
196 | np->avl_parent = child; | |
197 | child->avl_parent = parent; | |
198 | ||
199 | if (bal == AVL_BALANCE) { | |
200 | np->avl_balance = AVL_BACK; | |
201 | child->avl_balance = AVL_FORW; | |
202 | return; | |
203 | } else { | |
204 | np->avl_balance = AVL_BALANCE; | |
205 | child->avl_balance = AVL_BALANCE; | |
206 | np = parent; | |
207 | avl_checktree(tree, *rootp); | |
208 | continue; | |
209 | } | |
210 | } | |
211 | ||
212 | /* child->avl_balance == AVL_FORW double LR rotation | |
213 | * | |
214 | * child's avl_forw node gets promoted up, along with | |
215 | * its avl_forw subtree | |
216 | * | |
dfc130f3 | 217 | * np-> -G C |
2bd0ea18 NS |
218 | * / \ / \ |
219 | * child-> +B H -B G | |
220 | * / \ \ / / \ | |
221 | * A +C deleted A D H | |
222 | * \ | |
223 | * D | |
224 | */ | |
225 | #ifdef AVL_PRINT | |
226 | if (!(tree->avl_flags & AVLF_DUPLICITY)) | |
227 | cmn_err(CE_CONT, "!LR delete b 0x%x c 0x%x t 0x%x\n", | |
228 | np, child, child->avl_forw); | |
229 | #endif | |
230 | tmp = child->avl_forw; | |
231 | bal = tmp->avl_balance; | |
232 | ||
233 | child->avl_forw = tmp->avl_back; | |
234 | if (tmp->avl_back) | |
235 | tmp->avl_back->avl_parent = child; | |
236 | ||
237 | tmp->avl_back = child; | |
238 | child->avl_parent = tmp; | |
239 | ||
240 | np->avl_back = tmp->avl_forw; | |
241 | if (tmp->avl_forw) | |
242 | tmp->avl_forw->avl_parent = np; | |
243 | tmp->avl_forw = np; | |
244 | ||
245 | if (bal == AVL_FORW) | |
246 | child->avl_balance = AVL_BACK; | |
247 | else | |
248 | child->avl_balance = AVL_BALANCE; | |
249 | ||
250 | if (bal == AVL_BACK) | |
251 | np->avl_balance = AVL_FORW; | |
252 | else | |
253 | np->avl_balance = AVL_BALANCE; | |
254 | ||
255 | goto next; | |
256 | } | |
257 | ||
258 | ASSERT(np->avl_balance == AVL_FORW && direction == AVL_FORW); | |
259 | ||
260 | child = np->avl_forw; | |
261 | bal = child->avl_balance; | |
262 | ||
263 | if (bal != AVL_BACK) /* single RR */ { | |
264 | /* | |
265 | * np gets pushed down to greater child's | |
266 | * avl_back branch. | |
267 | * | |
dfc130f3 | 268 | * np-> +B -D |
2bd0ea18 NS |
269 | * / \ / \ |
270 | * deleted D <-child +B E | |
271 | * / \ \ | |
272 | * C E C | |
273 | */ | |
274 | #ifdef AVL_PRINT | |
275 | if (!(tree->avl_flags & AVLF_DUPLICITY)) | |
276 | cmn_err(CE_CONT, "!RR delete b 0x%x c 0x%x\n", | |
277 | np, child); | |
278 | #endif | |
279 | np->avl_forw = child->avl_back; | |
280 | if (child->avl_back) | |
281 | child->avl_back->avl_parent = np; | |
282 | child->avl_back = np; | |
283 | ||
284 | if (parent) { | |
285 | if (parent->avl_forw == np) { | |
286 | parent->avl_forw = child; | |
287 | direction = AVL_BACK; | |
288 | } else { | |
289 | ASSERT(parent->avl_back == np); | |
290 | parent->avl_back = child; | |
291 | direction = AVL_FORW; | |
292 | } | |
293 | } else { | |
294 | ASSERT(*rootp == np); | |
295 | *rootp = child; | |
296 | } | |
297 | np->avl_parent = child; | |
298 | child->avl_parent = parent; | |
299 | ||
300 | if (bal == AVL_BALANCE) { | |
301 | np->avl_balance = AVL_FORW; | |
302 | child->avl_balance = AVL_BACK; | |
303 | return; | |
304 | } else { | |
305 | np->avl_balance = AVL_BALANCE; | |
306 | child->avl_balance = AVL_BALANCE; | |
307 | np = parent; | |
308 | avl_checktree(tree, *rootp); | |
309 | continue; | |
310 | } | |
311 | } | |
312 | ||
313 | /* child->avl_balance == AVL_BACK double RL rotation */ | |
314 | #ifdef AVL_PRINT | |
315 | if (!(tree->avl_flags & AVLF_DUPLICITY)) | |
316 | cmn_err(CE_CONT, "!RL delete b 0x%x c 0x%x t 0x%x\n", | |
317 | np, child, child->avl_back); | |
318 | #endif | |
319 | tmp = child->avl_back; | |
320 | bal = tmp->avl_balance; | |
321 | ||
322 | child->avl_back = tmp->avl_forw; | |
323 | if (tmp->avl_forw) | |
324 | tmp->avl_forw->avl_parent = child; | |
325 | ||
326 | tmp->avl_forw = child; | |
327 | child->avl_parent = tmp; | |
328 | ||
329 | np->avl_forw = tmp->avl_back; | |
330 | if (tmp->avl_back) | |
331 | tmp->avl_back->avl_parent = np; | |
332 | tmp->avl_back = np; | |
333 | ||
334 | if (bal == AVL_BACK) | |
335 | child->avl_balance = AVL_FORW; | |
336 | else | |
337 | child->avl_balance = AVL_BALANCE; | |
338 | ||
339 | if (bal == AVL_FORW) | |
340 | np->avl_balance = AVL_BACK; | |
341 | else | |
342 | np->avl_balance = AVL_BALANCE; | |
343 | next: | |
344 | np->avl_parent = tmp; | |
345 | tmp->avl_balance = AVL_BALANCE; | |
346 | tmp->avl_parent = parent; | |
347 | ||
348 | if (parent) { | |
349 | if (parent->avl_forw == np) { | |
350 | parent->avl_forw = tmp; | |
351 | direction = AVL_BACK; | |
352 | } else { | |
353 | ASSERT(parent->avl_back == np); | |
354 | parent->avl_back = tmp; | |
355 | direction = AVL_FORW; | |
356 | } | |
357 | } else { | |
358 | ASSERT(*rootp == np); | |
359 | *rootp = tmp; | |
360 | return; | |
361 | } | |
362 | ||
363 | np = parent; | |
364 | avl_checktree(tree, *rootp); | |
365 | } while (np); | |
366 | } | |
367 | ||
368 | /* | |
369 | * Remove node from tree. | |
370 | * avl_delete does the local tree manipulations, | |
371 | * calls retreat() to rebalance tree up to its root. | |
372 | */ | |
373 | void | |
374 | avl_delete( | |
0c2a7d46 CH |
375 | avltree_desc_t *tree, |
376 | avlnode_t *np) | |
2bd0ea18 | 377 | { |
0c2a7d46 CH |
378 | avlnode_t *forw = np->avl_forw; |
379 | avlnode_t *back = np->avl_back; | |
380 | avlnode_t *parent = np->avl_parent; | |
381 | avlnode_t *nnext; | |
2bd0ea18 NS |
382 | |
383 | ||
384 | if (np->avl_back) { | |
385 | /* | |
386 | * a left child exits, then greatest left descendent's nextino | |
387 | * is pointing to np; make it point to np->nextino. | |
388 | */ | |
389 | nnext = np->avl_back; | |
390 | while (nnext) { | |
391 | if (!nnext->avl_forw) | |
392 | break; /* can't find anything bigger */ | |
393 | nnext = nnext->avl_forw; | |
394 | } | |
395 | } else | |
396 | if (np->avl_parent) { | |
397 | /* | |
398 | * find nearest ancestor with lesser value. That ancestor's | |
399 | * nextino is pointing to np; make it point to np->nextino | |
400 | */ | |
401 | nnext = np->avl_parent; | |
402 | while (nnext) { | |
403 | if (AVL_END(tree, nnext) <= AVL_END(tree, np)) | |
404 | break; | |
405 | nnext = nnext->avl_parent; | |
406 | } | |
407 | } else | |
408 | nnext = NULL; | |
409 | ||
410 | if (nnext) { | |
411 | ASSERT(nnext->avl_nextino == np); | |
412 | nnext->avl_nextino = np->avl_nextino; | |
413 | /* | |
dfc130f3 | 414 | * Something preceeds np; np cannot be firstino. |
2bd0ea18 NS |
415 | */ |
416 | ASSERT(tree->avl_firstino != np); | |
417 | } | |
418 | else { | |
419 | /* | |
dfc130f3 RC |
420 | * Nothing preceeding np; after deletion, np's nextino |
421 | * is firstino of tree. | |
2bd0ea18 NS |
422 | */ |
423 | ASSERT(tree->avl_firstino == np); | |
424 | tree->avl_firstino = np->avl_nextino; | |
425 | } | |
dfc130f3 | 426 | |
2bd0ea18 NS |
427 | |
428 | /* | |
429 | * Degenerate cases... | |
430 | */ | |
431 | if (forw == NULL) { | |
432 | forw = back; | |
433 | goto attach; | |
434 | } | |
435 | ||
436 | if (back == NULL) { | |
437 | attach: | |
438 | if (forw) | |
439 | forw->avl_parent = parent; | |
440 | if (parent) { | |
441 | if (parent->avl_forw == np) { | |
442 | parent->avl_forw = forw; | |
443 | retreat(tree, parent, AVL_BACK); | |
444 | } else { | |
445 | ASSERT(parent->avl_back == np); | |
446 | parent->avl_back = forw; | |
447 | retreat(tree, parent, AVL_FORW); | |
448 | } | |
449 | } else { | |
450 | ASSERT(tree->avl_root == np); | |
451 | tree->avl_root = forw; | |
452 | } | |
453 | avl_checktree(tree, tree->avl_root); | |
454 | return; | |
455 | } | |
456 | ||
457 | /* | |
458 | * Harder case: children on both sides. | |
459 | * If back's avl_forw pointer is null, just have back | |
460 | * inherit np's avl_forw tree, remove np from the tree | |
461 | * and adjust balance counters starting at back. | |
462 | * | |
463 | * np-> xI xH (befor retreat()) | |
464 | * / \ / \ | |
465 | * back-> H J G J | |
466 | * / / \ / \ | |
467 | * G ? ? ? ? | |
468 | * / \ | |
469 | * ? ? | |
470 | */ | |
471 | if ((forw = back->avl_forw) == NULL) { | |
472 | /* | |
473 | * AVL_FORW retreat below will set back's | |
474 | * balance to AVL_BACK. | |
475 | */ | |
476 | back->avl_balance = np->avl_balance; | |
477 | back->avl_forw = forw = np->avl_forw; | |
478 | forw->avl_parent = back; | |
479 | back->avl_parent = parent; | |
dfc130f3 | 480 | |
2bd0ea18 NS |
481 | if (parent) { |
482 | if (parent->avl_forw == np) | |
483 | parent->avl_forw = back; | |
484 | else { | |
485 | ASSERT(parent->avl_back == np); | |
486 | parent->avl_back = back; | |
487 | } | |
488 | } else { | |
489 | ASSERT(tree->avl_root == np); | |
490 | tree->avl_root = back; | |
491 | } | |
492 | ||
493 | /* | |
494 | * back is taking np's place in the tree, and | |
495 | * has therefore lost a avl_back node (itself). | |
496 | */ | |
497 | retreat(tree, back, AVL_FORW); | |
498 | avl_checktree(tree, tree->avl_root); | |
499 | return; | |
500 | } | |
501 | ||
502 | /* | |
503 | * Hardest case: children on both sides, and back's | |
504 | * avl_forw pointer isn't null. Find the immediately | |
505 | * inferior buffer by following back's avl_forw line | |
506 | * to the end, then have it inherit np's avl_forw tree. | |
507 | * | |
508 | * np-> xI xH | |
509 | * / \ / \ | |
510 | * G J back-> G J (before retreat()) | |
511 | * / \ / \ | |
dfc130f3 | 512 | * F ?... F ?1 |
2bd0ea18 NS |
513 | * / \ |
514 | * ? H <-forw | |
515 | * / | |
516 | * ?1 | |
517 | */ | |
27527004 | 518 | while ((back = forw->avl_forw)) |
2bd0ea18 NS |
519 | forw = back; |
520 | ||
521 | /* | |
522 | * Will be adjusted by retreat() below. | |
523 | */ | |
524 | forw->avl_balance = np->avl_balance; | |
dfc130f3 | 525 | |
2bd0ea18 NS |
526 | /* |
527 | * forw inherits np's avl_forw... | |
528 | */ | |
529 | forw->avl_forw = np->avl_forw; | |
530 | np->avl_forw->avl_parent = forw; | |
531 | ||
532 | /* | |
533 | * ... forw's parent gets forw's avl_back... | |
534 | */ | |
535 | back = forw->avl_parent; | |
536 | back->avl_forw = forw->avl_back; | |
537 | if (forw->avl_back) | |
538 | forw->avl_back->avl_parent = back; | |
539 | ||
540 | /* | |
541 | * ... forw gets np's avl_back... | |
542 | */ | |
543 | forw->avl_back = np->avl_back; | |
544 | np->avl_back->avl_parent = forw; | |
545 | ||
546 | /* | |
547 | * ... and forw gets np's parent. | |
548 | */ | |
549 | forw->avl_parent = parent; | |
550 | ||
551 | if (parent) { | |
552 | if (parent->avl_forw == np) | |
553 | parent->avl_forw = forw; | |
554 | else | |
555 | parent->avl_back = forw; | |
556 | } else { | |
557 | ASSERT(tree->avl_root == np); | |
558 | tree->avl_root = forw; | |
559 | } | |
560 | ||
561 | /* | |
562 | * What used to be forw's parent is the starting | |
563 | * point for rebalancing. It has lost a avl_forw node. | |
564 | */ | |
565 | retreat(tree, back, AVL_BACK); | |
566 | avl_checktree(tree, tree->avl_root); | |
567 | } | |
568 | ||
569 | ||
570 | /* | |
dfc130f3 RC |
571 | * avl_findanyrange: |
572 | * | |
2bd0ea18 NS |
573 | * Given range r [start, end), find any range which is contained in r. |
574 | * if checklen is non-zero, then only ranges of non-zero length are | |
dfc130f3 | 575 | * considered in finding a match. |
2bd0ea18 NS |
576 | */ |
577 | avlnode_t * | |
578 | avl_findanyrange( | |
0c2a7d46 | 579 | avltree_desc_t *tree, |
ee6cd73e CH |
580 | uintptr_t start, |
581 | uintptr_t end, | |
dfc130f3 | 582 | int checklen) |
2bd0ea18 | 583 | { |
0c2a7d46 | 584 | avlnode_t *np = tree->avl_root; |
2bd0ea18 NS |
585 | |
586 | /* np = avl_findadjacent(tree, start, AVL_SUCCEED); */ | |
587 | while (np) { | |
588 | if (start < AVL_START(tree, np)) { | |
589 | if (np->avl_back) { | |
590 | np = np->avl_back; | |
591 | continue; | |
592 | } | |
593 | /* if we were to add node with start, would | |
594 | * have a growth of AVL_BACK | |
595 | */ | |
596 | /* if succeeding node is needed, this is it. | |
597 | */ | |
598 | break; | |
599 | } | |
600 | if (start >= AVL_END(tree, np)) { | |
601 | if (np->avl_forw) { | |
602 | np = np->avl_forw; | |
603 | continue; | |
604 | } | |
605 | /* if we were to add node with start, would | |
dfc130f3 | 606 | * have a growth of AVL_FORW; |
2bd0ea18 NS |
607 | */ |
608 | /* we are looking for a succeeding node; | |
609 | * this is nextino. | |
610 | */ | |
611 | np = np->avl_nextino; | |
612 | break; | |
613 | } | |
614 | /* AVL_START(tree, np) <= start < AVL_END(tree, np) */ | |
615 | break; | |
616 | } | |
617 | if (np) { | |
618 | if (checklen == AVL_INCLUDE_ZEROLEN) { | |
619 | if (end <= AVL_START(tree, np)) { | |
620 | /* something follows start, but is | |
621 | * is entierly after the range (end) | |
622 | */ | |
623 | return(NULL); | |
624 | } | |
625 | /* np may stradle [start, end) */ | |
626 | return(np); | |
627 | } | |
628 | /* | |
dfc130f3 | 629 | * find non-zero length region |
2bd0ea18 NS |
630 | */ |
631 | while (np && (AVL_END(tree, np) - AVL_START(tree, np) == 0) | |
632 | && (AVL_START(tree, np) < end)) | |
633 | np = np->avl_nextino; | |
634 | ||
635 | if ((np == NULL) || (AVL_START(tree, np) >= end)) | |
636 | return NULL; | |
637 | return(np); | |
638 | } | |
639 | /* | |
640 | * nothing succeeds start, all existing ranges are before start. | |
641 | */ | |
642 | return NULL; | |
643 | } | |
644 | ||
2bd0ea18 NS |
645 | /* |
646 | * Returns a pointer to node which contains exact value. | |
647 | */ | |
648 | avlnode_t * | |
649 | avl_find( | |
0c2a7d46 | 650 | avltree_desc_t *tree, |
ee6cd73e | 651 | uintptr_t value) |
2bd0ea18 | 652 | { |
0c2a7d46 | 653 | avlnode_t *np = tree->avl_root; |
ee6cd73e | 654 | uintptr_t nvalue; |
2bd0ea18 NS |
655 | |
656 | while (np) { | |
657 | nvalue = AVL_START(tree, np); | |
658 | if (value < nvalue) { | |
659 | np = np->avl_back; | |
660 | continue; | |
661 | } | |
662 | if (value == nvalue) { | |
663 | return np; | |
664 | } | |
665 | np = np->avl_forw; | |
666 | } | |
667 | return NULL; | |
668 | } | |
669 | ||
670 | ||
671 | /* | |
672 | * Balance buffer AVL tree after attaching a new node to root. | |
673 | * Called only by avl_insert. | |
674 | */ | |
675 | static void | |
676 | avl_balance( | |
0c2a7d46 CH |
677 | avlnode_t **rootp, |
678 | avlnode_t *np, | |
679 | int growth) | |
2bd0ea18 NS |
680 | { |
681 | /* | |
682 | * At this point, np points to the node to which | |
683 | * a new node has been attached. All that remains is to | |
684 | * propagate avl_balance up the tree. | |
685 | */ | |
686 | for ( ; ; ) { | |
0c2a7d46 CH |
687 | avlnode_t *parent = np->avl_parent; |
688 | avlnode_t *child; | |
2bd0ea18 NS |
689 | |
690 | CERT(growth == AVL_BACK || growth == AVL_FORW); | |
691 | ||
692 | /* | |
693 | * If the buffer was already balanced, set avl_balance | |
694 | * to the new direction. Continue if there is a | |
695 | * parent after setting growth to reflect np's | |
696 | * relation to its parent. | |
697 | */ | |
698 | if (np->avl_balance == AVL_BALANCE) { | |
699 | np->avl_balance = growth; | |
700 | if (parent) { | |
701 | if (parent->avl_forw == np) | |
702 | growth = AVL_FORW; | |
703 | else { | |
704 | ASSERT(parent->avl_back == np); | |
705 | growth = AVL_BACK; | |
706 | } | |
707 | ||
708 | np = parent; | |
709 | continue; | |
710 | } | |
711 | break; | |
712 | } | |
713 | ||
714 | if (growth != np->avl_balance) { | |
715 | /* | |
716 | * Subtree is now balanced -- no net effect | |
717 | * in the size of the subtree, so leave. | |
718 | */ | |
719 | np->avl_balance = AVL_BALANCE; | |
720 | break; | |
721 | } | |
722 | ||
723 | if (growth == AVL_BACK) { | |
724 | ||
725 | child = np->avl_back; | |
726 | CERT(np->avl_balance == AVL_BACK && child); | |
727 | ||
728 | if (child->avl_balance == AVL_BACK) { /* single LL */ | |
729 | /* | |
730 | * ``A'' just got inserted; | |
731 | * np points to ``E'', child to ``C'', | |
732 | * and it is already AVL_BACK -- | |
733 | * child will get promoted to top of subtree. | |
734 | ||
735 | np-> -E C | |
736 | / \ / \ | |
737 | child-> -C F -B E | |
738 | / \ / / \ | |
739 | -B D A D F | |
740 | / | |
741 | A | |
742 | ||
743 | Note that child->avl_parent and | |
744 | avl_balance get set in common code. | |
745 | */ | |
746 | np->avl_parent = child; | |
747 | np->avl_balance = AVL_BALANCE; | |
748 | np->avl_back = child->avl_forw; | |
749 | if (child->avl_forw) | |
750 | child->avl_forw->avl_parent = np; | |
751 | child->avl_forw = np; | |
752 | } else { | |
753 | /* | |
754 | * double LR | |
755 | * | |
756 | * child's avl_forw node gets promoted to | |
757 | * the top of the subtree. | |
758 | ||
759 | np-> -E C | |
760 | / \ / \ | |
761 | child-> +B F -B E | |
762 | / \ / / \ | |
dfc130f3 | 763 | A +C A D F |
2bd0ea18 NS |
764 | \ |
765 | D | |
766 | ||
767 | */ | |
0c2a7d46 | 768 | avlnode_t *tmp = child->avl_forw; |
2bd0ea18 NS |
769 | |
770 | CERT(child->avl_balance == AVL_FORW && tmp); | |
771 | ||
772 | child->avl_forw = tmp->avl_back; | |
773 | if (tmp->avl_back) | |
774 | tmp->avl_back->avl_parent = child; | |
775 | ||
776 | tmp->avl_back = child; | |
777 | child->avl_parent = tmp; | |
778 | ||
779 | np->avl_back = tmp->avl_forw; | |
780 | if (tmp->avl_forw) | |
781 | tmp->avl_forw->avl_parent = np; | |
782 | ||
783 | tmp->avl_forw = np; | |
784 | np->avl_parent = tmp; | |
785 | ||
786 | if (tmp->avl_balance == AVL_BACK) | |
787 | np->avl_balance = AVL_FORW; | |
788 | else | |
789 | np->avl_balance = AVL_BALANCE; | |
790 | ||
791 | if (tmp->avl_balance == AVL_FORW) | |
792 | child->avl_balance = AVL_BACK; | |
793 | else | |
794 | child->avl_balance = AVL_BALANCE; | |
795 | ||
796 | /* | |
797 | * Set child to point to tmp since it is | |
798 | * now the top of the subtree, and will | |
799 | * get attached to the subtree parent in | |
800 | * the common code below. | |
801 | */ | |
802 | child = tmp; | |
803 | } | |
804 | ||
805 | } else /* growth == AVL_BACK */ { | |
806 | ||
807 | /* | |
808 | * This code is the mirror image of AVL_FORW above. | |
809 | */ | |
810 | ||
811 | child = np->avl_forw; | |
812 | CERT(np->avl_balance == AVL_FORW && child); | |
813 | ||
814 | if (child->avl_balance == AVL_FORW) { /* single RR */ | |
815 | np->avl_parent = child; | |
816 | np->avl_balance = AVL_BALANCE; | |
817 | np->avl_forw = child->avl_back; | |
818 | if (child->avl_back) | |
819 | child->avl_back->avl_parent = np; | |
820 | child->avl_back = np; | |
821 | } else { | |
822 | /* | |
823 | * double RL | |
824 | */ | |
0c2a7d46 | 825 | avlnode_t *tmp = child->avl_back; |
2bd0ea18 NS |
826 | |
827 | ASSERT(child->avl_balance == AVL_BACK && tmp); | |
828 | ||
829 | child->avl_back = tmp->avl_forw; | |
830 | if (tmp->avl_forw) | |
831 | tmp->avl_forw->avl_parent = child; | |
832 | ||
833 | tmp->avl_forw = child; | |
834 | child->avl_parent = tmp; | |
835 | ||
836 | np->avl_forw = tmp->avl_back; | |
837 | if (tmp->avl_back) | |
838 | tmp->avl_back->avl_parent = np; | |
839 | ||
840 | tmp->avl_back = np; | |
841 | np->avl_parent = tmp; | |
842 | ||
843 | if (tmp->avl_balance == AVL_FORW) | |
844 | np->avl_balance = AVL_BACK; | |
845 | else | |
846 | np->avl_balance = AVL_BALANCE; | |
847 | ||
848 | if (tmp->avl_balance == AVL_BACK) | |
849 | child->avl_balance = AVL_FORW; | |
850 | else | |
851 | child->avl_balance = AVL_BALANCE; | |
852 | ||
853 | child = tmp; | |
854 | } | |
855 | } | |
856 | ||
857 | child->avl_parent = parent; | |
858 | child->avl_balance = AVL_BALANCE; | |
859 | ||
860 | if (parent) { | |
861 | if (parent->avl_back == np) | |
862 | parent->avl_back = child; | |
863 | else | |
864 | parent->avl_forw = child; | |
865 | } else { | |
866 | ASSERT(*rootp == np); | |
867 | *rootp = child; | |
868 | } | |
869 | ||
870 | break; | |
871 | } | |
872 | } | |
873 | ||
874 | static | |
875 | avlnode_t * | |
876 | avl_insert_find_growth( | |
0c2a7d46 | 877 | avltree_desc_t *tree, |
ee6cd73e CH |
878 | uintptr_t start, /* range start at start, */ |
879 | uintptr_t end, /* exclusive */ | |
0c2a7d46 | 880 | int *growthp) /* OUT */ |
2bd0ea18 NS |
881 | { |
882 | avlnode_t *root = tree->avl_root; | |
0c2a7d46 | 883 | avlnode_t *np; |
2bd0ea18 NS |
884 | |
885 | np = root; | |
886 | ASSERT(np); /* caller ensures that there is atleast one node in tree */ | |
887 | ||
888 | for ( ; ; ) { | |
889 | CERT(np->avl_parent || root == np); | |
890 | CERT(!np->avl_parent || root != np); | |
891 | CERT(!(np->avl_back) || np->avl_back->avl_parent == np); | |
892 | CERT(!(np->avl_forw) || np->avl_forw->avl_parent == np); | |
893 | CERT(np->avl_balance != AVL_FORW || np->avl_forw); | |
894 | CERT(np->avl_balance != AVL_BACK || np->avl_back); | |
895 | CERT(np->avl_balance != AVL_BALANCE || | |
896 | np->avl_back == NULL || np->avl_forw); | |
897 | CERT(np->avl_balance != AVL_BALANCE || | |
898 | np->avl_forw == NULL || np->avl_back); | |
899 | ||
900 | if (AVL_START(tree, np) >= end) { | |
901 | if (np->avl_back) { | |
902 | np = np->avl_back; | |
903 | continue; | |
904 | } | |
905 | *growthp = AVL_BACK; | |
906 | break; | |
907 | } | |
908 | ||
909 | if (AVL_END(tree, np) <= start) { | |
910 | if (np->avl_forw) { | |
911 | np = np->avl_forw; | |
912 | continue; | |
913 | } | |
914 | *growthp = AVL_FORW; | |
915 | break; | |
916 | } | |
917 | /* found exact match -- let caller decide if it is an error */ | |
918 | return(NULL); | |
919 | } | |
920 | return(np); | |
921 | } | |
922 | ||
923 | ||
924 | static void | |
925 | avl_insert_grow( | |
0c2a7d46 CH |
926 | avltree_desc_t *tree, |
927 | avlnode_t *parent, | |
928 | avlnode_t *newnode, | |
929 | int growth) | |
2bd0ea18 | 930 | { |
0c2a7d46 | 931 | avlnode_t *nnext; |
ee6cd73e | 932 | uintptr_t start = AVL_START(tree, newnode); |
2bd0ea18 NS |
933 | |
934 | if (growth == AVL_BACK) { | |
935 | ||
936 | parent->avl_back = newnode; | |
937 | /* | |
938 | * we are growing to the left; previous in-order to newnode is | |
939 | * closest ancestor with lesser value. Before this | |
940 | * insertion, this ancestor will be pointing to | |
941 | * newnode's parent. After insertion, next in-order to newnode | |
942 | * is the parent. | |
943 | */ | |
944 | newnode->avl_nextino = parent; | |
945 | nnext = parent; | |
946 | while (nnext) { | |
947 | if (AVL_END(tree, nnext) <= start) | |
948 | break; | |
949 | nnext = nnext->avl_parent; | |
950 | } | |
951 | if (nnext) { | |
952 | /* | |
953 | * nnext will be null if newnode is | |
954 | * the least element, and hence very first in the list. | |
955 | */ | |
956 | ASSERT(nnext->avl_nextino == parent); | |
957 | nnext->avl_nextino = newnode; | |
958 | } | |
959 | } | |
960 | else { | |
961 | parent->avl_forw = newnode; | |
962 | newnode->avl_nextino = parent->avl_nextino; | |
963 | parent->avl_nextino = newnode; | |
964 | } | |
965 | } | |
966 | ||
967 | ||
968 | avlnode_t * | |
969 | avl_insert( | |
0c2a7d46 CH |
970 | avltree_desc_t *tree, |
971 | avlnode_t *newnode) | |
2bd0ea18 | 972 | { |
0c2a7d46 | 973 | avlnode_t *np; |
ee6cd73e CH |
974 | uintptr_t start = AVL_START(tree, newnode); |
975 | uintptr_t end = AVL_END(tree, newnode); | |
2bd0ea18 NS |
976 | int growth; |
977 | ||
978 | ASSERT(newnode); | |
979 | ASSERT(start <= end); | |
980 | ||
981 | /* | |
982 | * Clean all pointers for sanity; some will be reset as necessary. | |
983 | */ | |
984 | newnode->avl_nextino = NULL; | |
985 | newnode->avl_parent = NULL; | |
986 | newnode->avl_forw = NULL; | |
987 | newnode->avl_back = NULL; | |
988 | newnode->avl_balance = AVL_BALANCE; | |
989 | ||
990 | if ((np = tree->avl_root) == NULL) { /* degenerate case... */ | |
991 | tree->avl_root = newnode; | |
992 | tree->avl_firstino = newnode; | |
993 | return newnode; | |
994 | } | |
995 | ||
996 | if ((np = avl_insert_find_growth(tree, start, end, &growth)) == NULL) { | |
997 | if (start != end) { /* non-zero length range */ | |
2d9475a4 | 998 | fprintf(stderr, |
507f4e33 | 999 | _("avl_insert: Warning! duplicate range [%llu,%llu]\n"), |
2d9475a4 NS |
1000 | (unsigned long long)start, |
1001 | (unsigned long long)end); | |
2bd0ea18 NS |
1002 | } |
1003 | return(NULL); | |
1004 | } | |
1005 | ||
1006 | avl_insert_grow(tree, np, newnode, growth); | |
1007 | if (growth == AVL_BACK) { | |
1008 | /* | |
1009 | * Growing to left. if np was firstino, newnode will be firstino | |
1010 | */ | |
1011 | if (tree->avl_firstino == np) | |
1012 | tree->avl_firstino = newnode; | |
1013 | } | |
1014 | #ifdef notneeded | |
1015 | else | |
1016 | if (growth == AVL_FORW) | |
1017 | /* | |
1018 | * Cannot possibly be firstino; there is somebody to our left. | |
1019 | */ | |
1020 | ; | |
1021 | #endif | |
1022 | ||
1023 | newnode->avl_parent = np; | |
1024 | CERT(np->avl_forw == newnode || np->avl_back == newnode); | |
1025 | ||
1026 | avl_balance(&tree->avl_root, np, growth); | |
1027 | ||
1028 | avl_checktree(tree, tree->avl_root); | |
1029 | ||
1030 | return newnode; | |
1031 | } | |
1032 | ||
1033 | /* | |
1034 | * | |
1035 | * avl_insert_immediate(tree, afterp, newnode): | |
dfc130f3 | 1036 | * insert newnode immediately into tree immediately after afterp. |
2bd0ea18 NS |
1037 | * after insertion, newnode is right child of afterp. |
1038 | */ | |
1039 | void | |
1040 | avl_insert_immediate( | |
1041 | avltree_desc_t *tree, | |
1042 | avlnode_t *afterp, | |
1043 | avlnode_t *newnode) | |
1044 | { | |
1045 | /* | |
1046 | * Clean all pointers for sanity; some will be reset as necessary. | |
1047 | */ | |
1048 | newnode->avl_nextino = NULL; | |
1049 | newnode->avl_parent = NULL; | |
1050 | newnode->avl_forw = NULL; | |
1051 | newnode->avl_back = NULL; | |
1052 | newnode->avl_balance = AVL_BALANCE; | |
1053 | ||
1054 | if (afterp == NULL) { | |
1055 | tree->avl_root = newnode; | |
1056 | tree->avl_firstino = newnode; | |
1057 | return; | |
1058 | } | |
1059 | ||
1060 | ASSERT(afterp->avl_forw == NULL); | |
1061 | avl_insert_grow(tree, afterp, newnode, AVL_FORW); /* grow to right */ | |
1062 | CERT(afterp->avl_forw == newnode); | |
1063 | avl_balance(&tree->avl_root, afterp, AVL_FORW); | |
1064 | avl_checktree(tree, tree->avl_root); | |
1065 | } | |
1066 | ||
1067 | ||
1068 | /* | |
1069 | * Returns first in order node | |
1070 | */ | |
1071 | avlnode_t * | |
0c2a7d46 | 1072 | avl_firstino(avlnode_t *root) |
2bd0ea18 | 1073 | { |
0c2a7d46 | 1074 | avlnode_t *np; |
2bd0ea18 NS |
1075 | |
1076 | if ((np = root) == NULL) | |
1077 | return NULL; | |
1078 | ||
1079 | while (np->avl_back) | |
1080 | np = np->avl_back; | |
1081 | return np; | |
1082 | } | |
1083 | ||
2bd0ea18 NS |
1084 | /* |
1085 | * Returns last in order node | |
1086 | */ | |
1087 | avlnode_t * | |
0c2a7d46 | 1088 | avl_lastino(avlnode_t *root) |
2bd0ea18 | 1089 | { |
0c2a7d46 | 1090 | avlnode_t *np; |
2bd0ea18 NS |
1091 | |
1092 | if ((np = root) == NULL) | |
1093 | return NULL; | |
1094 | ||
1095 | while (np->avl_forw) | |
1096 | np = np->avl_forw; | |
1097 | return np; | |
1098 | } | |
2bd0ea18 NS |
1099 | |
1100 | void | |
1101 | avl_init_tree(avltree_desc_t *tree, avlops_t *ops) | |
1102 | { | |
1103 | tree->avl_root = NULL; | |
1104 | tree->avl_firstino = NULL; | |
1105 | tree->avl_ops = ops; | |
1106 | } | |
1107 | ||
1108 | #ifdef AVL_DEBUG | |
1109 | static void | |
1110 | avl_printnode(avltree_desc_t *tree, avlnode_t *np, int nl) | |
1111 | { | |
1112 | printf("[%d-%d]%c", AVL_START(tree, np), | |
1113 | (AVL_END(tree, np) - 1), nl ? '\n' : ' '); | |
1114 | } | |
1115 | #endif | |
1116 | #ifdef STAND_ALONE_DEBUG | |
1117 | ||
1118 | struct avl_debug_node { | |
1119 | avlnode_t avl_node; | |
1120 | xfs_off_t avl_start; | |
1121 | unsigned int avl_size; | |
1122 | } | |
1123 | ||
1124 | avlops_t avl_debug_ops = { | |
1125 | avl_debug_start, | |
1126 | avl_debug_end, | |
1127 | } | |
1128 | ||
ee6cd73e | 1129 | static uintptr_t |
2bd0ea18 NS |
1130 | avl_debug_start(avlnode_t *node) |
1131 | { | |
ee6cd73e | 1132 | return (uintptr_t)(struct avl_debug_node *)node->avl_start; |
2bd0ea18 NS |
1133 | } |
1134 | ||
ee6cd73e | 1135 | static uintptr_t |
2bd0ea18 NS |
1136 | avl_debug_end(avlnode_t *node) |
1137 | { | |
ee6cd73e | 1138 | return (uintptr_t) |
2bd0ea18 NS |
1139 | ((struct avl_debug_node *)node->avl_start + |
1140 | (struct avl_debug_node *)node->avl_size); | |
1141 | } | |
1142 | ||
dfc130f3 RC |
1143 | avl_debug_node freenodes[100]; |
1144 | avl_debug_node *freehead = &freenodes[0]; | |
2bd0ea18 NS |
1145 | |
1146 | static avlnode_t * | |
1147 | alloc_avl_debug_node() | |
1148 | { | |
1149 | freehead->avl_balance = AVL_BALANCE; | |
1150 | freehead->avl_parent = freehead->avl_forw = freehead->avl_back = NULL; | |
1151 | return(freehead++); | |
1152 | } | |
1153 | ||
1154 | static void | |
1155 | avl_print(avltree_desc_t *tree, avlnode_t *root, int depth) | |
1156 | { | |
1157 | int i; | |
1158 | ||
1159 | if (!root) | |
1160 | return; | |
1161 | if (root->avl_forw) | |
1162 | avl_print(tree, root->avl_forw, depth+5); | |
1163 | for (i = 0; i < depth; i++) | |
1164 | putchar((int) ' '); | |
1165 | avl_printnode(tree, root,1); | |
1166 | if (root->avl_back) | |
1167 | avl_print(tree, root->avl_back, depth+5); | |
1168 | } | |
1169 | ||
1170 | main() | |
1171 | { | |
dfc130f3 RC |
1172 | int i, j; |
1173 | avlnode_t *np; | |
2bd0ea18 NS |
1174 | avltree_desc_t tree; |
1175 | char linebuf[256], cmd[256]; | |
1176 | ||
1177 | avl_init_tree(&tree, &avl_debug_ops); | |
1178 | ||
1179 | for (i = 100; i > 0; i = i - 10) | |
dfc130f3 | 1180 | { |
2bd0ea18 NS |
1181 | np = alloc__debug_avlnode(); |
1182 | ASSERT(np); | |
1183 | np->avl_start = i; | |
1184 | np->avl_size = 10; | |
1185 | avl_insert(&tree, np); | |
1186 | } | |
1187 | avl_print(&tree, tree.avl_root, 0); | |
1188 | ||
1189 | for (np = tree.avl_firstino; np != NULL; np = np->avl_nextino) | |
1190 | avl_printnode(&tree, np, 0); | |
1191 | printf("\n"); | |
1192 | ||
1193 | while (1) { | |
9ee7055c | 1194 | printf(_("Command [fpdir] : ")); |
2bd0ea18 NS |
1195 | fgets(linebuf, 256, stdin); |
1196 | if (feof(stdin)) break; | |
1197 | cmd[0] = NULL; | |
1198 | if (sscanf(linebuf, "%[fpdir]%d", cmd, &i) != 2) | |
1199 | continue; | |
1200 | switch (cmd[0]) { | |
1201 | case 'd': | |
1202 | case 'f': | |
9ee7055c | 1203 | printf(_("end of range ? ")); |
2bd0ea18 NS |
1204 | fgets(linebuf, 256, stdin); |
1205 | j = atoi(linebuf); | |
1206 | ||
1207 | if (i == j) j = i+1; | |
1208 | np = avl_findinrange(&tree,i,j); | |
1209 | if (np) { | |
1210 | avl_printnode(&tree, np, 1); | |
1211 | if (cmd[0] == 'd') | |
1212 | avl_delete(&tree, np); | |
1213 | } else | |
9ee7055c | 1214 | printf(_("Cannot find %d\n"), i); |
2bd0ea18 NS |
1215 | break; |
1216 | case 'p': | |
1217 | avl_print(&tree, tree.avl_root, 0); | |
1218 | for (np = tree.avl_firstino; | |
1219 | np != NULL; np = np->avl_nextino) | |
1220 | avl_printnode(&tree, np, 0); | |
1221 | printf("\n"); | |
1222 | break; | |
1223 | case 'i': | |
1224 | np = alloc_avlnode(); | |
1225 | ASSERT(np); | |
1226 | np->avl_start = i; | |
9ee7055c | 1227 | printf(_("size of range ? ")); |
2bd0ea18 NS |
1228 | fgets(linebuf, 256, stdin); |
1229 | j = atoi(linebuf); | |
1230 | ||
1231 | np->avl_size = j; | |
1232 | avl_insert(&tree, np); | |
1233 | break; | |
1234 | case 'r': { | |
dfc130f3 | 1235 | avlnode_t *b, *e, *t; |
2bd0ea18 NS |
1236 | int checklen; |
1237 | ||
9ee7055c | 1238 | printf(_("End of range ? ")); |
2bd0ea18 NS |
1239 | fgets(linebuf, 256, stdin); |
1240 | j = atoi(linebuf); | |
1241 | ||
9ee7055c | 1242 | printf(_("checklen 0/1 ? ")); |
2bd0ea18 NS |
1243 | fgets(linebuf, 256, stdin); |
1244 | checklen = atoi(linebuf); | |
1245 | ||
1246 | ||
1247 | b = avl_findanyrange(&tree, i, j, checklen); | |
1248 | if (b) { | |
9ee7055c | 1249 | printf(_("Found something\n")); |
2bd0ea18 NS |
1250 | t = b; |
1251 | while (t) { | |
1252 | if (t != b && | |
1253 | AVL_START(&tree, t) >= j) | |
1254 | break; | |
1255 | avl_printnode(&tree, t, 0); | |
1256 | t = t->avl_nextino; | |
1257 | } | |
1258 | printf("\n"); | |
1259 | } | |
1260 | } | |
1261 | } | |
1262 | } | |
1263 | } | |
1264 | #endif | |
1265 | ||
1266 | /* | |
dfc130f3 | 1267 | * Given a tree, find value; will find return range enclosing value, |
2bd0ea18 | 1268 | * or range immediately succeeding value, |
dfc130f3 | 1269 | * or range immediately preceeding value. |
2bd0ea18 NS |
1270 | */ |
1271 | avlnode_t * | |
1272 | avl_findadjacent( | |
0c2a7d46 | 1273 | avltree_desc_t *tree, |
ee6cd73e | 1274 | uintptr_t value, |
0c2a7d46 | 1275 | int dir) |
2bd0ea18 | 1276 | { |
0c2a7d46 | 1277 | avlnode_t *np = tree->avl_root; |
2bd0ea18 NS |
1278 | |
1279 | while (np) { | |
1280 | if (value < AVL_START(tree, np)) { | |
1281 | if (np->avl_back) { | |
1282 | np = np->avl_back; | |
1283 | continue; | |
1284 | } | |
1285 | /* if we were to add node with value, would | |
1286 | * have a growth of AVL_BACK | |
1287 | */ | |
1288 | if (dir == AVL_SUCCEED) { | |
1289 | /* if succeeding node is needed, this is it. | |
1290 | */ | |
1291 | return(np); | |
1292 | } | |
1293 | if (dir == AVL_PRECEED) { | |
1294 | /* | |
1295 | * find nearest ancestor with lesser value. | |
1296 | */ | |
1297 | np = np->avl_parent; | |
1298 | while (np) { | |
1299 | if (AVL_END(tree, np) <= value) | |
1300 | break; | |
1301 | np = np->avl_parent; | |
1302 | } | |
1303 | return(np); | |
1304 | } | |
1305 | ASSERT(dir == AVL_SUCCEED || dir == AVL_PRECEED); | |
1306 | break; | |
1307 | } | |
1308 | if (value >= AVL_END(tree, np)) { | |
1309 | if (np->avl_forw) { | |
1310 | np = np->avl_forw; | |
1311 | continue; | |
1312 | } | |
1313 | /* if we were to add node with value, would | |
dfc130f3 | 1314 | * have a growth of AVL_FORW; |
2bd0ea18 NS |
1315 | */ |
1316 | if (dir == AVL_SUCCEED) { | |
1317 | /* we are looking for a succeeding node; | |
1318 | * this is nextino. | |
1319 | */ | |
1320 | return(np->avl_nextino); | |
1321 | } | |
1322 | if (dir == AVL_PRECEED) { | |
1323 | /* looking for a preceeding node; this is it. */ | |
1324 | return(np); | |
dfc130f3 | 1325 | } |
2bd0ea18 NS |
1326 | ASSERT(dir == AVL_SUCCEED || dir == AVL_PRECEED); |
1327 | } | |
1328 | /* AVL_START(tree, np) <= value < AVL_END(tree, np) */ | |
1329 | return(np); | |
1330 | } | |
1331 | return NULL; | |
1332 | } | |
1333 | ||
1334 | ||
2bd0ea18 | 1335 | /* |
dfc130f3 | 1336 | * avl_findranges: |
2bd0ea18 NS |
1337 | * |
1338 | * Given range r [start, end), find all ranges in tree which are contained | |
1339 | * in r. At return, startp and endp point to first and last of | |
dfc130f3 | 1340 | * a chain of elements which describe the contained ranges. Elements |
2bd0ea18 NS |
1341 | * in startp ... endp are in sort order, and can be accessed by |
1342 | * using avl_nextino. | |
1343 | */ | |
1344 | ||
1345 | void | |
1346 | avl_findranges( | |
0c2a7d46 | 1347 | avltree_desc_t *tree, |
ee6cd73e CH |
1348 | uintptr_t start, |
1349 | uintptr_t end, | |
dfc130f3 | 1350 | avlnode_t **startp, |
2bd0ea18 NS |
1351 | avlnode_t **endp) |
1352 | { | |
0c2a7d46 | 1353 | avlnode_t *np; |
2bd0ea18 NS |
1354 | |
1355 | np = avl_findadjacent(tree, start, AVL_SUCCEED); | |
dfc130f3 | 1356 | if (np == NULL /* nothing succeding start */ |
2bd0ea18 NS |
1357 | || (np && (end <= AVL_START(tree, np)))) |
1358 | /* something follows start, | |
1359 | but... is entirely after end */ | |
1360 | { | |
1361 | *startp = NULL; | |
1362 | *endp = NULL; | |
1363 | return; | |
1364 | } | |
1365 | ||
1366 | *startp = np; | |
1367 | ||
1368 | /* see if end is in this region itself */ | |
1369 | if (end <= AVL_END(tree, np) || | |
1370 | np->avl_nextino == NULL || | |
1371 | (np->avl_nextino && | |
1372 | (end <= AVL_START(tree, np->avl_nextino)))) { | |
1373 | *endp = np; | |
1374 | return; | |
1375 | } | |
1376 | /* have to munge for end */ | |
1377 | /* | |
1378 | * note: have to look for (end - 1), since | |
1379 | * findadjacent will look for exact value, and does not | |
1380 | * care about the fact that end is actually one more | |
1381 | * than the value actually being looked for; thus feed it one less. | |
1382 | */ | |
1383 | *endp = avl_findadjacent(tree, (end-1), AVL_PRECEED); | |
1384 | ASSERT(*endp); | |
1385 | } |