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Diffstat (limited to 'src/util/container_heap.c')
-rw-r--r-- | src/util/container_heap.c | 562 |
1 files changed, 0 insertions, 562 deletions
diff --git a/src/util/container_heap.c b/src/util/container_heap.c deleted file mode 100644 index 35d7cd4ab..000000000 --- a/src/util/container_heap.c +++ /dev/null | |||
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1 | /* | ||
2 | This file is part of GNUnet. | ||
3 | Copyright (C) 2008, 2009 GNUnet e.V. | ||
4 | |||
5 | GNUnet is free software: you can redistribute it and/or modify it | ||
6 | under the terms of the GNU Affero General Public License as published | ||
7 | by the Free Software Foundation, either version 3 of the License, | ||
8 | or (at your option) any later version. | ||
9 | |||
10 | GNUnet is distributed in the hope that it will be useful, but | ||
11 | WITHOUT ANY WARRANTY; without even the implied warranty of | ||
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | ||
13 | Affero General Public License for more details. | ||
14 | |||
15 | You should have received a copy of the GNU Affero General Public License | ||
16 | along with this program. If not, see <http://www.gnu.org/licenses/>. | ||
17 | |||
18 | SPDX-License-Identifier: AGPL3.0-or-later | ||
19 | */ | ||
20 | |||
21 | /** | ||
22 | * @file util/container_heap.c | ||
23 | * @brief Implementation of a heap | ||
24 | * @author Nathan Evans | ||
25 | * @author Christian Grothoff | ||
26 | */ | ||
27 | |||
28 | #include "platform.h" | ||
29 | #include "gnunet_container_lib.h" | ||
30 | |||
31 | #define LOG(kind, ...) GNUNET_log_from (kind, "util-container-heap", \ | ||
32 | __VA_ARGS__) | ||
33 | |||
34 | #define EXTRA_CHECKS 0 | ||
35 | |||
36 | /** | ||
37 | * Node in the heap. | ||
38 | */ | ||
39 | struct GNUNET_CONTAINER_HeapNode | ||
40 | { | ||
41 | /** | ||
42 | * Heap this node belongs to. | ||
43 | */ | ||
44 | struct GNUNET_CONTAINER_Heap *heap; | ||
45 | |||
46 | /** | ||
47 | * Parent node. | ||
48 | */ | ||
49 | struct GNUNET_CONTAINER_HeapNode *parent; | ||
50 | |||
51 | /** | ||
52 | * Left child. | ||
53 | */ | ||
54 | struct GNUNET_CONTAINER_HeapNode *left_child; | ||
55 | |||
56 | /** | ||
57 | * Right child. | ||
58 | */ | ||
59 | struct GNUNET_CONTAINER_HeapNode *right_child; | ||
60 | |||
61 | /** | ||
62 | * Our element. | ||
63 | */ | ||
64 | void *element; | ||
65 | |||
66 | /** | ||
67 | * Cost for this element. | ||
68 | */ | ||
69 | GNUNET_CONTAINER_HeapCostType cost; | ||
70 | |||
71 | /** | ||
72 | * Number of elements below this node in the heap | ||
73 | * (excluding this node itself). | ||
74 | */ | ||
75 | unsigned int tree_size; | ||
76 | }; | ||
77 | |||
78 | /** | ||
79 | * Handle to a node in a heap. | ||
80 | */ | ||
81 | struct GNUNET_CONTAINER_Heap | ||
82 | { | ||
83 | /** | ||
84 | * Root of the heap. | ||
85 | */ | ||
86 | struct GNUNET_CONTAINER_HeapNode *root; | ||
87 | |||
88 | /** | ||
89 | * Current position of our random walk. | ||
90 | */ | ||
91 | struct GNUNET_CONTAINER_HeapNode *walk_pos; | ||
92 | |||
93 | /** | ||
94 | * Number of elements in the heap. | ||
95 | */ | ||
96 | unsigned int size; | ||
97 | |||
98 | /** | ||
99 | * How is the heap sorted? | ||
100 | */ | ||
101 | enum GNUNET_CONTAINER_HeapOrder order; | ||
102 | }; | ||
103 | |||
104 | |||
105 | #if EXTRA_CHECKS | ||
106 | /** | ||
107 | * Check if internal invariants hold for the given node. | ||
108 | * | ||
109 | * @param node subtree to check | ||
110 | */ | ||
111 | static void | ||
112 | check (const struct GNUNET_CONTAINER_HeapNode *node) | ||
113 | { | ||
114 | if (NULL == node) | ||
115 | return; | ||
116 | GNUNET_assert (node->tree_size == | ||
117 | ((node->left_child == | ||
118 | NULL) ? 0 : 1 + node->left_child->tree_size) | ||
119 | + ((node->right_child == | ||
120 | NULL) ? 0 : 1 + node->right_child->tree_size)); | ||
121 | check (node->left_child); | ||
122 | check (node->right_child); | ||
123 | } | ||
124 | |||
125 | |||
126 | #define CHECK(n) check (n) | ||
127 | #else | ||
128 | #define CHECK(n) do {} while (0) | ||
129 | #endif | ||
130 | |||
131 | |||
132 | /** | ||
133 | * Create a new heap. | ||
134 | * | ||
135 | * @param order how should the heap be sorted? | ||
136 | * @return handle to the heap | ||
137 | */ | ||
138 | struct GNUNET_CONTAINER_Heap * | ||
139 | GNUNET_CONTAINER_heap_create (enum GNUNET_CONTAINER_HeapOrder order) | ||
140 | { | ||
141 | struct GNUNET_CONTAINER_Heap *heap; | ||
142 | |||
143 | heap = GNUNET_new (struct GNUNET_CONTAINER_Heap); | ||
144 | heap->order = order; | ||
145 | return heap; | ||
146 | } | ||
147 | |||
148 | |||
149 | /** | ||
150 | * Destroys the heap. Only call on a heap that | ||
151 | * is already empty. | ||
152 | * | ||
153 | * @param heap heap to destroy | ||
154 | */ | ||
155 | void | ||
156 | GNUNET_CONTAINER_heap_destroy (struct GNUNET_CONTAINER_Heap *heap) | ||
157 | { | ||
158 | GNUNET_break (heap->size == 0); | ||
159 | GNUNET_free (heap); | ||
160 | } | ||
161 | |||
162 | |||
163 | /** | ||
164 | * Get element stored at the root of @a heap. | ||
165 | * | ||
166 | * @param heap Heap to inspect. | ||
167 | * @return Element at the root, or NULL if heap is empty. | ||
168 | */ | ||
169 | void * | ||
170 | GNUNET_CONTAINER_heap_peek (const struct GNUNET_CONTAINER_Heap *heap) | ||
171 | { | ||
172 | if (heap->root == NULL) | ||
173 | return NULL; | ||
174 | return heap->root->element; | ||
175 | } | ||
176 | |||
177 | |||
178 | /** | ||
179 | * Get @a element and @a cost stored at the root of @a heap. | ||
180 | * | ||
181 | * @param[in] heap Heap to inspect. | ||
182 | * @param[out] element Root element is returned here. | ||
183 | * @param[out] cost Cost of @a element is returned here. | ||
184 | * @return #GNUNET_YES if an element is returned, | ||
185 | * #GNUNET_NO if the heap is empty. | ||
186 | */ | ||
187 | int | ||
188 | GNUNET_CONTAINER_heap_peek2 (const struct GNUNET_CONTAINER_Heap *heap, | ||
189 | void **element, | ||
190 | GNUNET_CONTAINER_HeapCostType *cost) | ||
191 | { | ||
192 | if (NULL == heap->root) | ||
193 | return GNUNET_NO; | ||
194 | if (NULL != element) | ||
195 | *element = heap->root->element; | ||
196 | if (NULL != cost) | ||
197 | *cost = heap->root->cost; | ||
198 | return GNUNET_YES; | ||
199 | } | ||
200 | |||
201 | |||
202 | /** | ||
203 | * Get the current size of the heap | ||
204 | * | ||
205 | * @param heap the heap to get the size of | ||
206 | * @return number of elements stored | ||
207 | */ | ||
208 | unsigned int | ||
209 | GNUNET_CONTAINER_heap_get_size (const struct GNUNET_CONTAINER_Heap *heap) | ||
210 | { | ||
211 | return heap->size; | ||
212 | } | ||
213 | |||
214 | |||
215 | /** | ||
216 | * Get the current cost of the node | ||
217 | * | ||
218 | * @param node the node to get the cost of | ||
219 | * @return cost of the node | ||
220 | */ | ||
221 | GNUNET_CONTAINER_HeapCostType | ||
222 | GNUNET_CONTAINER_heap_node_get_cost (const struct GNUNET_CONTAINER_HeapNode | ||
223 | *node) | ||
224 | { | ||
225 | return node->cost; | ||
226 | } | ||
227 | |||
228 | |||
229 | /** | ||
230 | * Iterate over the children of the given node. | ||
231 | * | ||
232 | * @param heap argument to give to iterator | ||
233 | * @param node node to iterate over | ||
234 | * @param iterator function to call on each node | ||
235 | * @param iterator_cls closure for iterator | ||
236 | * @return GNUNET_YES to continue to iterate | ||
237 | */ | ||
238 | static int | ||
239 | node_iterator (const struct GNUNET_CONTAINER_Heap *heap, | ||
240 | struct GNUNET_CONTAINER_HeapNode *node, | ||
241 | GNUNET_CONTAINER_HeapIterator iterator, void *iterator_cls) | ||
242 | { | ||
243 | if (node == NULL) | ||
244 | return GNUNET_YES; | ||
245 | if (GNUNET_YES != | ||
246 | node_iterator (heap, node->left_child, iterator, iterator_cls)) | ||
247 | return GNUNET_NO; | ||
248 | if (GNUNET_YES != | ||
249 | node_iterator (heap, node->right_child, iterator, iterator_cls)) | ||
250 | return GNUNET_NO; | ||
251 | return iterator (iterator_cls, node, node->element, node->cost); | ||
252 | } | ||
253 | |||
254 | |||
255 | /** | ||
256 | * Iterate over all entries in the heap. | ||
257 | * | ||
258 | * @param heap the heap | ||
259 | * @param iterator function to call on each entry | ||
260 | * @param iterator_cls closure for iterator | ||
261 | */ | ||
262 | void | ||
263 | GNUNET_CONTAINER_heap_iterate (const struct GNUNET_CONTAINER_Heap *heap, | ||
264 | GNUNET_CONTAINER_HeapIterator iterator, | ||
265 | void *iterator_cls) | ||
266 | { | ||
267 | (void) node_iterator (heap, heap->root, iterator, iterator_cls); | ||
268 | } | ||
269 | |||
270 | |||
271 | /** | ||
272 | * Perform a random walk of the tree. The walk is biased | ||
273 | * towards elements closer to the root of the tree (since | ||
274 | * each walk starts at the root and ends at a random leaf). | ||
275 | * The heap internally tracks the current position of the | ||
276 | * walk. | ||
277 | * | ||
278 | * @param heap heap to walk | ||
279 | * @return data stored at the next random node in the walk; | ||
280 | * NULL if the tree is empty. | ||
281 | */ | ||
282 | void * | ||
283 | GNUNET_CONTAINER_heap_walk_get_next (struct GNUNET_CONTAINER_Heap *heap) | ||
284 | { | ||
285 | struct GNUNET_CONTAINER_HeapNode *pos; | ||
286 | void *element; | ||
287 | |||
288 | if (heap->root == NULL) | ||
289 | return NULL; | ||
290 | pos = heap->walk_pos; | ||
291 | if (pos == NULL) | ||
292 | pos = heap->root; | ||
293 | element = pos->element; | ||
294 | heap->walk_pos = | ||
295 | (0 == | ||
296 | GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK, | ||
297 | 2)) ? pos->right_child : pos->left_child; | ||
298 | return element; | ||
299 | } | ||
300 | |||
301 | |||
302 | /** | ||
303 | * Insert the given node 'node' into the subtree starting | ||
304 | * at 'pos' (while keeping the tree somewhat balanced). | ||
305 | * | ||
306 | * @param heap heap to modify | ||
307 | * @param pos existing tree | ||
308 | * @param node node to insert (which may be a subtree itself) | ||
309 | */ | ||
310 | static void | ||
311 | insert_node (struct GNUNET_CONTAINER_Heap *heap, | ||
312 | struct GNUNET_CONTAINER_HeapNode *pos, | ||
313 | struct GNUNET_CONTAINER_HeapNode *node) | ||
314 | { | ||
315 | struct GNUNET_CONTAINER_HeapNode *parent; | ||
316 | |||
317 | GNUNET_assert (node->parent == NULL); | ||
318 | while ((heap->order == GNUNET_CONTAINER_HEAP_ORDER_MAX) ? (pos->cost >= | ||
319 | node->cost) | ||
320 | : (pos->cost <= node->cost)) | ||
321 | { | ||
322 | /* node is descendent of pos */ | ||
323 | pos->tree_size += (1 + node->tree_size); | ||
324 | if (pos->left_child == NULL) | ||
325 | { | ||
326 | pos->left_child = node; | ||
327 | node->parent = pos; | ||
328 | return; | ||
329 | } | ||
330 | if (pos->right_child == NULL) | ||
331 | { | ||
332 | pos->right_child = node; | ||
333 | node->parent = pos; | ||
334 | return; | ||
335 | } | ||
336 | /* keep it balanced by descending into smaller subtree */ | ||
337 | if (pos->left_child->tree_size < pos->right_child->tree_size) | ||
338 | pos = pos->left_child; | ||
339 | else | ||
340 | pos = pos->right_child; | ||
341 | } | ||
342 | /* make 'node' parent of 'pos' */ | ||
343 | parent = pos->parent; | ||
344 | pos->parent = NULL; | ||
345 | node->parent = parent; | ||
346 | if (NULL == parent) | ||
347 | { | ||
348 | heap->root = node; | ||
349 | } | ||
350 | else | ||
351 | { | ||
352 | if (parent->left_child == pos) | ||
353 | parent->left_child = node; | ||
354 | else | ||
355 | parent->right_child = node; | ||
356 | } | ||
357 | /* insert 'pos' below 'node' */ | ||
358 | insert_node (heap, node, pos); | ||
359 | CHECK (pos); | ||
360 | } | ||
361 | |||
362 | |||
363 | /** | ||
364 | * Inserts a new element into the heap. | ||
365 | * | ||
366 | * @param heap heap to modify | ||
367 | * @param element element to insert | ||
368 | * @param cost cost for the element | ||
369 | * @return node for the new element | ||
370 | */ | ||
371 | struct GNUNET_CONTAINER_HeapNode * | ||
372 | GNUNET_CONTAINER_heap_insert (struct GNUNET_CONTAINER_Heap *heap, void *element, | ||
373 | GNUNET_CONTAINER_HeapCostType cost) | ||
374 | { | ||
375 | struct GNUNET_CONTAINER_HeapNode *node; | ||
376 | |||
377 | node = GNUNET_new (struct GNUNET_CONTAINER_HeapNode); | ||
378 | node->heap = heap; | ||
379 | node->element = element; | ||
380 | node->cost = cost; | ||
381 | heap->size++; | ||
382 | if (NULL == heap->root) | ||
383 | heap->root = node; | ||
384 | else | ||
385 | insert_node (heap, heap->root, node); | ||
386 | GNUNET_assert (heap->size == heap->root->tree_size + 1); | ||
387 | CHECK (heap->root); | ||
388 | return node; | ||
389 | } | ||
390 | |||
391 | |||
392 | /** | ||
393 | * Remove root of the heap. | ||
394 | * | ||
395 | * @param heap heap to modify | ||
396 | * @return element data stored at the root node, NULL if heap is empty | ||
397 | */ | ||
398 | void * | ||
399 | GNUNET_CONTAINER_heap_remove_root (struct GNUNET_CONTAINER_Heap *heap) | ||
400 | { | ||
401 | void *ret; | ||
402 | struct GNUNET_CONTAINER_HeapNode *root; | ||
403 | |||
404 | if (NULL == (root = heap->root)) | ||
405 | return NULL; | ||
406 | heap->size--; | ||
407 | ret = root->element; | ||
408 | if (root->left_child == NULL) | ||
409 | { | ||
410 | heap->root = root->right_child; | ||
411 | if (root->right_child != NULL) | ||
412 | root->right_child->parent = NULL; | ||
413 | } | ||
414 | else if (root->right_child == NULL) | ||
415 | { | ||
416 | heap->root = root->left_child; | ||
417 | root->left_child->parent = NULL; | ||
418 | } | ||
419 | else | ||
420 | { | ||
421 | root->left_child->parent = NULL; | ||
422 | root->right_child->parent = NULL; | ||
423 | heap->root = root->left_child; | ||
424 | insert_node (heap, heap->root, root->right_child); | ||
425 | } | ||
426 | if (heap->walk_pos == root) | ||
427 | heap->walk_pos = heap->root; | ||
428 | GNUNET_free (root); | ||
429 | #if EXTRA_CHECKS | ||
430 | GNUNET_assert (((heap->size == 0) && (heap->root == NULL)) || | ||
431 | (heap->size == heap->root->tree_size + 1)); | ||
432 | CHECK (heap->root); | ||
433 | #endif | ||
434 | return ret; | ||
435 | } | ||
436 | |||
437 | |||
438 | /** | ||
439 | * Remove the given node 'node' from the tree and update | ||
440 | * the 'tree_size' fields accordingly. Preserves the | ||
441 | * children of 'node' and does NOT change the overall | ||
442 | * 'size' field of the tree. | ||
443 | */ | ||
444 | static void | ||
445 | remove_node (struct GNUNET_CONTAINER_HeapNode *node) | ||
446 | { | ||
447 | struct GNUNET_CONTAINER_HeapNode *ancestor; | ||
448 | struct GNUNET_CONTAINER_Heap *heap = node->heap; | ||
449 | |||
450 | /* update 'size' of the ancestors */ | ||
451 | ancestor = node; | ||
452 | while (NULL != (ancestor = ancestor->parent)) | ||
453 | ancestor->tree_size--; | ||
454 | |||
455 | /* update 'size' of node itself */ | ||
456 | if (node->left_child != NULL) | ||
457 | node->tree_size -= (1 + node->left_child->tree_size); | ||
458 | if (node->right_child != NULL) | ||
459 | node->tree_size -= (1 + node->right_child->tree_size); | ||
460 | |||
461 | /* unlink 'node' itself and insert children in its place */ | ||
462 | if (node->parent == NULL) | ||
463 | { | ||
464 | if (node->left_child != NULL) | ||
465 | { | ||
466 | heap->root = node->left_child; | ||
467 | node->left_child->parent = NULL; | ||
468 | if (node->right_child != NULL) | ||
469 | { | ||
470 | node->right_child->parent = NULL; | ||
471 | insert_node (heap, heap->root, node->right_child); | ||
472 | } | ||
473 | } | ||
474 | else | ||
475 | { | ||
476 | heap->root = node->right_child; | ||
477 | if (node->right_child != NULL) | ||
478 | node->right_child->parent = NULL; | ||
479 | } | ||
480 | } | ||
481 | else | ||
482 | { | ||
483 | if (node->parent->left_child == node) | ||
484 | node->parent->left_child = NULL; | ||
485 | else | ||
486 | node->parent->right_child = NULL; | ||
487 | if (node->left_child != NULL) | ||
488 | { | ||
489 | node->left_child->parent = NULL; | ||
490 | node->parent->tree_size -= (1 + node->left_child->tree_size); | ||
491 | insert_node (heap, node->parent, node->left_child); | ||
492 | } | ||
493 | if (node->right_child != NULL) | ||
494 | { | ||
495 | node->right_child->parent = NULL; | ||
496 | node->parent->tree_size -= (1 + node->right_child->tree_size); | ||
497 | insert_node (heap, node->parent, node->right_child); | ||
498 | } | ||
499 | } | ||
500 | node->parent = NULL; | ||
501 | node->left_child = NULL; | ||
502 | node->right_child = NULL; | ||
503 | GNUNET_assert (node->tree_size == 0); | ||
504 | CHECK (heap->root); | ||
505 | } | ||
506 | |||
507 | |||
508 | /** | ||
509 | * Removes a node from the heap. | ||
510 | * | ||
511 | * @param node node to remove | ||
512 | * @return element data stored at the node | ||
513 | */ | ||
514 | void * | ||
515 | GNUNET_CONTAINER_heap_remove_node (struct GNUNET_CONTAINER_HeapNode *node) | ||
516 | { | ||
517 | void *ret; | ||
518 | struct GNUNET_CONTAINER_Heap *heap; | ||
519 | |||
520 | heap = node->heap; | ||
521 | CHECK (heap->root); | ||
522 | if (heap->walk_pos == node) | ||
523 | (void) GNUNET_CONTAINER_heap_walk_get_next (heap); | ||
524 | remove_node (node); | ||
525 | heap->size--; | ||
526 | ret = node->element; | ||
527 | if (heap->walk_pos == node) | ||
528 | heap->walk_pos = NULL; | ||
529 | GNUNET_free (node); | ||
530 | #if EXTRA_CHECKS | ||
531 | CHECK (heap->root); | ||
532 | GNUNET_assert (((heap->size == 0) && (heap->root == NULL)) || | ||
533 | (heap->size == heap->root->tree_size + 1)); | ||
534 | #endif | ||
535 | return ret; | ||
536 | } | ||
537 | |||
538 | |||
539 | /** | ||
540 | * Updates the cost of any node in the tree | ||
541 | * | ||
542 | * @param node node for which the cost is to be changed | ||
543 | * @param new_cost new cost for the node | ||
544 | */ | ||
545 | void | ||
546 | GNUNET_CONTAINER_heap_update_cost (struct GNUNET_CONTAINER_HeapNode *node, | ||
547 | GNUNET_CONTAINER_HeapCostType new_cost) | ||
548 | { | ||
549 | struct GNUNET_CONTAINER_Heap *heap = node->heap; | ||
550 | |||
551 | remove_node (node); | ||
552 | node->cost = new_cost; | ||
553 | if (NULL == heap->root) | ||
554 | heap->root = node; | ||
555 | else | ||
556 | insert_node (heap, | ||
557 | heap->root, | ||
558 | node); | ||
559 | } | ||
560 | |||
561 | |||
562 | /* end of heap.c */ | ||