Use xoshiro256** to generate pseudo-random numbers.
[tinc] / src / splay_tree.c
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
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
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
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
277 void splay_free_tree(splay_tree_t *tree) {
278         free(tree);
279 }
280
281 splay_node_t *splay_alloc_node(void) {
282         return xzalloc(sizeof(splay_node_t));
283 }
284
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
607 void splay_empty_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         tree->head = NULL;
614         tree->tail = NULL;
615         tree->root = NULL;
616         tree->count = 0;
617         tree->generation++;
618 }
619
620 void splay_delete_tree(splay_tree_t *tree) {
621         splay_empty_tree(tree);
622         splay_free_tree(tree);
623 }
624
625 /* Tree walking */
626
627 void splay_foreach(const splay_tree_t *tree, splay_action_t action) {
628         for(splay_node_t *node = tree->head, *next; node; node = next) {
629                 next = node->next;
630                 action(node->data);
631         }
632 }
633
634 void splay_foreach_node(const splay_tree_t *tree, splay_action_t action) {
635         for(splay_node_t *node = tree->head, *next; node; node = next) {
636                 next = node->next;
637                 action(node);
638         }
639 }