1 /*
2 splay_tree.c -- splay tree and linked list convenience
3 Copyright (C) 2004-2013 Guus Sliepen <guus@tinc-vpn.org>
4
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 2 of the License, or
8 (at your option) any later version.
9
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
14
15 You should have received a copy of the GNU General Public License along
16 with this program; if not, write to the Free Software Foundation, Inc.,
17 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
18 */
19
20 #include "system.h"
21
22 #include "splay_tree.h"
23 #include "xalloc.h"
24
25 /* Splay operation */
26
splay_top_down(splay_tree_t * tree,const void * data,int * result)27 static splay_node_t *splay_top_down(splay_tree_t *tree, const void *data, int *result) {
28 splay_node_t left = {0}, right = {0};
29 splay_node_t *leftbottom = &left, *rightbottom = &right, *child, *grandchild;
30 splay_node_t *root = tree->root;
31 int c;
32
33 if(!root) {
34 if(result) {
35 *result = 0;
36 }
37
38 return NULL;
39 }
40
41 while((c = tree->compare(data, root->data))) {
42 if(c < 0 && (child = root->left)) {
43 c = tree->compare(data, child->data);
44
45 if(c < 0 && (grandchild = child->left)) {
46 rightbottom->left = child;
47 child->parent = rightbottom;
48 rightbottom = child;
49
50 if((root->left = child->right)) {
51 child->right->parent = root;
52 }
53
54 child->right = root;
55 root->parent = child;
56
57 child->left = NULL;
58 grandchild->parent = NULL;
59
60 root = grandchild;
61 } else if(c > 0 && (grandchild = child->right)) {
62 leftbottom->right = child;
63 child->parent = leftbottom;
64 leftbottom = child;
65
66 child->right = NULL;
67 grandchild->parent = NULL;
68
69 rightbottom->left = root;
70 root->parent = rightbottom;
71 rightbottom = root;
72
73 root->left = NULL;
74
75 root = grandchild;
76 } else {
77 rightbottom->left = root;
78 root->parent = rightbottom;
79 rightbottom = root;
80
81 root->left = NULL;
82 child->parent = NULL;
83
84 root = child;
85 break;
86 }
87 } else if(c > 0 && (child = root->right)) {
88 c = tree->compare(data, child->data);
89
90 if(c > 0 && (grandchild = child->right)) {
91 leftbottom->right = child;
92 child->parent = leftbottom;
93 leftbottom = child;
94
95 if((root->right = child->left)) {
96 child->left->parent = root;
97 }
98
99 child->left = root;
100 root->parent = child;
101
102 child->right = NULL;
103 grandchild->parent = NULL;
104
105 root = grandchild;
106 } else if(c < 0 && (grandchild = child->left)) {
107 rightbottom->left = child;
108 child->parent = rightbottom;
109 rightbottom = child;
110
111 child->left = NULL;
112 grandchild->parent = NULL;
113
114 leftbottom->right = root;
115 root->parent = leftbottom;
116 leftbottom = root;
117
118 root->right = NULL;
119
120 root = grandchild;
121 } else {
122 leftbottom->right = root;
123 root->parent = leftbottom;
124 leftbottom = root;
125
126 root->right = NULL;
127 child->parent = NULL;
128
129 root = child;
130 break;
131 }
132 } else {
133 break;
134 }
135 }
136
137 /* Merge trees */
138
139 if(left.right) {
140 if(root->left) {
141 leftbottom->right = root->left;
142 root->left->parent = leftbottom;
143 }
144
145 root->left = left.right;
146 left.right->parent = root;
147 }
148
149 if(right.left) {
150 if(root->right) {
151 rightbottom->left = root->right;
152 root->right->parent = rightbottom;
153 }
154
155 root->right = right.left;
156 right.left->parent = root;
157 }
158
159 /* Return result */
160
161 tree->root = root;
162
163 if(result) {
164 *result = c;
165 }
166
167 return tree->root;
168 }
169
splay_bottom_up(splay_tree_t * tree,splay_node_t * node)170 static void splay_bottom_up(splay_tree_t *tree, splay_node_t *node) {
171 splay_node_t *parent, *grandparent, *greatgrandparent;
172
173 while((parent = node->parent)) {
174 if(!(grandparent = parent->parent)) { /* zig */
175 if(node == parent->left) {
176 if((parent->left = node->right)) {
177 parent->left->parent = parent;
178 }
179
180 node->right = parent;
181 } else {
182 if((parent->right = node->left)) {
183 parent->right->parent = parent;
184 }
185
186 node->left = parent;
187 }
188
189 parent->parent = node;
190 node->parent = NULL;
191 } else {
192 greatgrandparent = grandparent->parent;
193
194 if(node == parent->left && parent == grandparent->left) { /* left zig-zig */
195 if((grandparent->left = parent->right)) {
196 grandparent->left->parent = grandparent;
197 }
198
199 parent->right = grandparent;
200 grandparent->parent = parent;
201
202 if((parent->left = node->right)) {
203 parent->left->parent = parent;
204 }
205
206 node->right = parent;
207 parent->parent = node;
208 } else if(node == parent->right && parent == grandparent->right) { /* right zig-zig */
209 if((grandparent->right = parent->left)) {
210 grandparent->right->parent = grandparent;
211 }
212
213 parent->left = grandparent;
214 grandparent->parent = parent;
215
216 if((parent->right = node->left)) {
217 parent->right->parent = parent;
218 }
219
220 node->left = parent;
221 parent->parent = node;
222 } else if(node == parent->right && parent == grandparent->left) { /* left-right zig-zag */
223 if((parent->right = node->left)) {
224 parent->right->parent = parent;
225 }
226
227 node->left = parent;
228 parent->parent = node;
229
230 if((grandparent->left = node->right)) {
231 grandparent->left->parent = grandparent;
232 }
233
234 node->right = grandparent;
235 grandparent->parent = node;
236 } else { /* right-left zig-zag */
237 if((parent->left = node->right)) {
238 parent->left->parent = parent;
239 }
240
241 node->right = parent;
242 parent->parent = node;
243
244 if((grandparent->right = node->left)) {
245 grandparent->right->parent = grandparent;
246 }
247
248 node->left = grandparent;
249 grandparent->parent = node;
250 }
251
252 if((node->parent = greatgrandparent)) {
253 if(grandparent == greatgrandparent->left) {
254 greatgrandparent->left = node;
255 } else {
256 greatgrandparent->right = node;
257 }
258 }
259 }
260 }
261
262 tree->root = node;
263 }
264
265 /* (De)constructors */
266
splay_alloc_tree(splay_compare_t compare,splay_action_t delete)267 splay_tree_t *splay_alloc_tree(splay_compare_t compare, splay_action_t delete) {
268 splay_tree_t *tree;
269
270 tree = xzalloc(sizeof(splay_tree_t));
271 tree->compare = compare;
272 tree->delete = delete;
273
274 return tree;
275 }
276
splay_free_tree(splay_tree_t * tree)277 void splay_free_tree(splay_tree_t *tree) {
278 free(tree);
279 }
280
splay_alloc_node(void)281 splay_node_t *splay_alloc_node(void) {
282 return xzalloc(sizeof(splay_node_t));
283 }
284
splay_free_node(splay_tree_t * tree,splay_node_t * node)285 void splay_free_node(splay_tree_t *tree, splay_node_t *node) {
286 if(node->data && tree->delete) {
287 tree->delete(node->data);
288 }
289
290 free(node);
291 }
292
293 /* Searching */
294
splay_search(splay_tree_t * tree,const void * data)295 void *splay_search(splay_tree_t *tree, const void *data) {
296 splay_node_t *node;
297
298 node = splay_search_node(tree, data);
299
300 return node ? node->data : NULL;
301 }
302
splay_search_closest(splay_tree_t * tree,const void * data,int * result)303 void *splay_search_closest(splay_tree_t *tree, const void *data, int *result) {
304 splay_node_t *node;
305
306 node = splay_search_closest_node(tree, data, result);
307
308 return node ? node->data : NULL;
309 }
310
splay_search_closest_smaller(splay_tree_t * tree,const void * data)311 void *splay_search_closest_smaller(splay_tree_t *tree, const void *data) {
312 splay_node_t *node;
313
314 node = splay_search_closest_smaller_node(tree, data);
315
316 return node ? node->data : NULL;
317 }
318
splay_search_closest_greater(splay_tree_t * tree,const void * data)319 void *splay_search_closest_greater(splay_tree_t *tree, const void *data) {
320 splay_node_t *node;
321
322 node = splay_search_closest_greater_node(tree, data);
323
324 return node ? node->data : NULL;
325 }
326
splay_search_node(splay_tree_t * tree,const void * data)327 splay_node_t *splay_search_node(splay_tree_t *tree, const void *data) {
328 splay_node_t *node;
329 int result;
330
331 node = splay_search_closest_node(tree, data, &result);
332
333 return result ? NULL : node;
334 }
335
splay_search_closest_node_nosplay(const splay_tree_t * tree,const void * data,int * result)336 splay_node_t *splay_search_closest_node_nosplay(const splay_tree_t *tree, const void *data, int *result) {
337 splay_node_t *node;
338 int c;
339
340 node = tree->root;
341
342 if(!node) {
343 if(result) {
344 *result = 0;
345 }
346
347 return NULL;
348 }
349
350 for(;;) {
351 c = tree->compare(data, node->data);
352
353 if(c < 0) {
354 if(node->left) {
355 node = node->left;
356 } else {
357 break;
358 }
359 } else if(c > 0) {
360 if(node->right) {
361 node = node->right;
362 } else {
363 break;
364 }
365 } else {
366 break;
367 }
368 }
369
370 if(result) {
371 *result = c;
372 }
373
374 return node;
375 }
376
splay_search_closest_node(splay_tree_t * tree,const void * data,int * result)377 splay_node_t *splay_search_closest_node(splay_tree_t *tree, const void *data, int *result) {
378 return splay_top_down(tree, data, result);
379 }
380
splay_search_closest_smaller_node(splay_tree_t * tree,const void * data)381 splay_node_t *splay_search_closest_smaller_node(splay_tree_t *tree, const void *data) {
382 splay_node_t *node;
383 int result;
384
385 node = splay_search_closest_node(tree, data, &result);
386
387 if(result < 0) {
388 node = node->prev;
389 }
390
391 return node;
392 }
393
splay_search_closest_greater_node(splay_tree_t * tree,const void * data)394 splay_node_t *splay_search_closest_greater_node(splay_tree_t *tree, const void *data) {
395 splay_node_t *node;
396 int result;
397
398 node = splay_search_closest_node(tree, data, &result);
399
400 if(result > 0) {
401 node = node->next;
402 }
403
404 return node;
405 }
406
407 /* Insertion and deletion */
408
splay_insert(splay_tree_t * tree,void * data)409 splay_node_t *splay_insert(splay_tree_t *tree, void *data) {
410 splay_node_t *closest, *new;
411 int result;
412
413 if(!tree->root) {
414 new = splay_alloc_node();
415 new->data = data;
416 splay_insert_top(tree, new);
417 } else {
418 closest = splay_search_closest_node(tree, data, &result);
419
420 if(!result) {
421 return NULL;
422 }
423
424 new = splay_alloc_node();
425 new->data = data;
426
427 if(result < 0) {
428 splay_insert_before(tree, closest, new);
429 } else {
430 splay_insert_after(tree, closest, new);
431 }
432 }
433
434 return new;
435 }
436
splay_insert_node(splay_tree_t * tree,splay_node_t * node)437 splay_node_t *splay_insert_node(splay_tree_t *tree, splay_node_t *node) {
438 splay_node_t *closest;
439 int result;
440
441 node->left = node->right = node->parent = node->next = node->prev = NULL;
442
443 if(!tree->root) {
444 splay_insert_top(tree, node);
445 } else {
446 closest = splay_search_closest_node(tree, node->data, &result);
447
448 if(!result) {
449 return NULL;
450 }
451
452 if(result < 0) {
453 splay_insert_before(tree, closest, node);
454 } else {
455 splay_insert_after(tree, closest, node);
456 }
457 }
458
459 return node;
460 }
461
splay_insert_top(splay_tree_t * tree,splay_node_t * node)462 void splay_insert_top(splay_tree_t *tree, splay_node_t *node) {
463 node->prev = node->next = node->left = node->right = node->parent = NULL;
464 tree->head = tree->tail = tree->root = node;
465 tree->count++;
466 tree->generation++;
467 }
468
splay_insert_before(splay_tree_t * tree,splay_node_t * before,splay_node_t * node)469 void splay_insert_before(splay_tree_t *tree, splay_node_t *before, splay_node_t *node) {
470 if(!before) {
471 if(tree->tail) {
472 splay_insert_after(tree, tree->tail, node);
473 } else {
474 splay_insert_top(tree, node);
475 }
476
477 return;
478 }
479
480 node->next = before;
481
482 if((node->prev = before->prev)) {
483 before->prev->next = node;
484 } else {
485 tree->head = node;
486 }
487
488 before->prev = node;
489
490 splay_bottom_up(tree, before);
491
492 node->right = before;
493 before->parent = node;
494
495 if((node->left = before->left)) {
496 before->left->parent = node;
497 }
498
499 before->left = NULL;
500
501 node->parent = NULL;
502 tree->root = node;
503 tree->count++;
504 tree->generation++;
505 }
506
splay_insert_after(splay_tree_t * tree,splay_node_t * after,splay_node_t * node)507 void splay_insert_after(splay_tree_t *tree, splay_node_t *after, splay_node_t *node) {
508 if(!after) {
509 if(tree->head) {
510 splay_insert_before(tree, tree->head, node);
511 } else {
512 splay_insert_top(tree, node);
513 }
514
515 return;
516 }
517
518 node->prev = after;
519
520 if((node->next = after->next)) {
521 after->next->prev = node;
522 } else {
523 tree->tail = node;
524 }
525
526 after->next = node;
527
528 splay_bottom_up(tree, after);
529
530 node->left = after;
531 after->parent = node;
532
533 if((node->right = after->right)) {
534 after->right->parent = node;
535 }
536
537 after->right = NULL;
538
539 node->parent = NULL;
540 tree->root = node;
541 tree->count++;
542 tree->generation++;
543 }
544
splay_unlink(splay_tree_t * tree,void * data)545 splay_node_t *splay_unlink(splay_tree_t *tree, void *data) {
546 splay_node_t *node;
547
548 node = splay_search_node(tree, data);
549
550 if(node) {
551 splay_unlink_node(tree, node);
552 }
553
554 return node;
555 }
556
splay_unlink_node(splay_tree_t * tree,splay_node_t * node)557 void splay_unlink_node(splay_tree_t *tree, splay_node_t *node) {
558 if(node->prev) {
559 node->prev->next = node->next;
560 } else {
561 tree->head = node->next;
562 }
563
564 if(node->next) {
565 node->next->prev = node->prev;
566 } else {
567 tree->tail = node->prev;
568 }
569
570 splay_bottom_up(tree, node);
571
572 if(node->prev) {
573 node->left->parent = NULL;
574 tree->root = node->left;
575
576 if((node->prev->right = node->right)) {
577 node->right->parent = node->prev;
578 }
579 } else if(node->next) {
580 tree->root = node->right;
581 node->right->parent = NULL;
582 } else {
583 tree->root = NULL;
584 }
585
586 tree->count--;
587 tree->generation++;
588 }
589
splay_delete_node(splay_tree_t * tree,splay_node_t * node)590 void splay_delete_node(splay_tree_t *tree, splay_node_t *node) {
591 splay_unlink_node(tree, node);
592 splay_free_node(tree, node);
593 }
594
splay_delete(splay_tree_t * tree,void * data)595 void splay_delete(splay_tree_t *tree, void *data) {
596 splay_node_t *node;
597
598 node = splay_search_node(tree, data);
599
600 if(node) {
601 splay_delete_node(tree, node);
602 }
603 }
604
605 /* Fast tree cleanup */
606
splay_delete_tree(splay_tree_t * tree)607 void splay_delete_tree(splay_tree_t *tree) {
608 for(splay_node_t *node = tree->head, *next; node; node = next) {
609 next = node->next;
610 splay_free_node(tree, node);
611 }
612
613 splay_free_tree(tree);
614 }
615
616 /* Tree walking */
617
splay_foreach(const splay_tree_t * tree,splay_action_t action)618 void splay_foreach(const splay_tree_t *tree, splay_action_t action) {
619 for(splay_node_t *node = tree->head, *next; node; node = next) {
620 next = node->next;
621 action(node->data);
622 }
623 }
624
splay_foreach_node(const splay_tree_t * tree,splay_action_t action)625 void splay_foreach_node(const splay_tree_t *tree, splay_action_t action) {
626 for(splay_node_t *node = tree->head, *next; node; node = next) {
627 next = node->next;
628 action(node);
629 }
630 }
631