2 This file is part of GNUnet.
3 (C) 2008 Christian Grothoff (and other contributing authors)
5 GNUnet is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published
7 by the Free Software Foundation; either version 2, or (at your
8 option) any later version.
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 General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with GNUnet; see the file COPYING. If not, write to the
17 Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18 Boston, MA 02111-1307, USA.
22 * @author Nathan Evans
23 * @file util/container_heap.c
24 * @brief Implementation of heap operations
28 #include "gnunet_protocols.h"
29 #include "gnunet_util_lib.h"
32 * Struct that is stored in hashmap, pointers to
33 * locations in min_heap and max_heap.
35 struct GNUNET_CONTAINER_heap_info
37 struct GNUNET_CONTAINER_heap_node *min_loc;
39 struct GNUNET_CONTAINER_heap_node *max_loc;
44 * Generic heap node structure, contains pointer to parent
45 * left child, right child, and actual neighbor.
47 struct GNUNET_CONTAINER_heap_node
49 struct GNUNET_CONTAINER_heap_node *parent;
51 struct GNUNET_CONTAINER_heap_node *left_child;
53 struct GNUNET_CONTAINER_heap_node *right_child;
55 GNUNET_CONTAINER_HeapCost cost;
61 struct GNUNET_CONTAINER_Heap
65 unsigned int max_size;
67 enum GNUNET_CONTAINER_HeapOrder type;
69 struct GNUNET_CONTAINER_heap_node *root;
71 struct GNUNET_CONTAINER_heap_node *traversal_pos;
77 * Returns element stored at root of tree, doesn't effect anything
79 * @param heap the heap
80 * @return NULL if the heap is empty
82 void *GNUNET_CONTAINER_heap_peek (struct GNUNET_CONTAINER_Heap *heap)
84 if ((heap == NULL) || (heap->root == NULL))
87 return heap->root->element;
92 internal_print (struct GNUNET_CONTAINER_heap_node *root)
94 fprintf (stdout, "%llu\n", (unsigned long long) root->cost);
95 if (root->left_child != NULL)
97 fprintf (stdout, "LEFT of %llu\n", (unsigned long long) root->cost);
98 internal_print (root->left_child);
100 if (root->right_child != NULL)
102 fprintf (stdout, "RIGHT of %llu\n", (unsigned long long) root->cost);
103 internal_print (root->right_child);
108 printTree (struct GNUNET_CONTAINER_Heap *root)
110 internal_print (root->root);
113 struct GNUNET_CONTAINER_Heap *
114 GNUNET_CONTAINER_heap_create (enum GNUNET_CONTAINER_HeapOrder type)
116 struct GNUNET_CONTAINER_Heap *heap;
117 heap = malloc (sizeof (struct GNUNET_CONTAINER_Heap));
121 heap->traversal_pos = NULL;
128 GNUNET_CONTAINER_heap_destroy (struct GNUNET_CONTAINER_Heap *heap)
130 while (heap->size > 0)
131 GNUNET_CONTAINER_heap_remove_root (heap);
136 struct GNUNET_CONTAINER_heap_node *
137 find_element (struct GNUNET_CONTAINER_heap_node *node, void *element)
139 struct GNUNET_CONTAINER_heap_node *ret;
144 if (node->element == element)
147 if (node->left_child != NULL)
148 ret = find_element (node->left_child, element);
150 if (node->right_child != NULL)
151 ret = find_element (node->right_child, element);
156 static struct GNUNET_CONTAINER_heap_node *
157 getNextPos (struct GNUNET_CONTAINER_Heap *root)
159 struct GNUNET_CONTAINER_heap_node *ret;
160 struct GNUNET_CONTAINER_heap_node *parent;
165 ret = GNUNET_malloc (sizeof (struct GNUNET_CONTAINER_heap_node));
166 pos = root->size + 1;
167 depth = (int) log2 (pos);
168 ret->left_child = NULL;
169 ret->right_child = NULL;
179 for (i = depth; i > 1; i--)
181 if (((pos / (1 << (i - 1))) % 2) == 0)
182 parent = parent->left_child;
184 parent = parent->right_child;
187 ret->parent = parent;
189 parent->left_child = ret;
191 parent->right_child = ret;
199 static struct GNUNET_CONTAINER_heap_node *
200 getPos (struct GNUNET_CONTAINER_Heap *root, unsigned int pos)
202 struct GNUNET_CONTAINER_heap_node *ret;
207 depth = (int) log2 (pos);
209 if (pos > root->size)
216 for (i = depth; i > 0; i--)
218 if (((pos / (1 << (i - 1))) % 2) == 0)
219 ret = ret->left_child;
221 ret = ret->right_child;
230 swapNodes (struct GNUNET_CONTAINER_heap_node *first,
231 struct GNUNET_CONTAINER_heap_node *second,
232 struct GNUNET_CONTAINER_Heap *root)
235 GNUNET_CONTAINER_HeapCost temp_cost;
237 temp_element = first->element;
238 temp_cost = first->cost;
239 first->element = second->element;
240 first->cost = second->cost;
241 second->element = temp_element;
242 second->cost = temp_cost;
248 percolateHeap (struct GNUNET_CONTAINER_heap_node *pos,
249 struct GNUNET_CONTAINER_Heap *root)
252 while ((pos->parent != NULL) &&
253 (((root->type == GNUNET_CONTAINER_HEAP_ORDER_MAX)
254 && (pos->parent->cost < pos->cost))
255 || ((root->type == GNUNET_CONTAINER_HEAP_ORDER_MIN)
256 && (pos->parent->cost > pos->cost))))
258 swapNodes (pos, pos->parent, root);
268 percolateDownHeap (struct GNUNET_CONTAINER_heap_node *pos,
269 struct GNUNET_CONTAINER_Heap *root)
271 struct GNUNET_CONTAINER_heap_node *switchNeighbor;
273 switchNeighbor = pos;
275 if ((root->type == GNUNET_CONTAINER_HEAP_ORDER_MAX))
277 if ((pos->left_child != NULL)
278 && (pos->left_child->cost > switchNeighbor->cost))
280 switchNeighbor = pos->left_child;
283 if ((pos->right_child != NULL)
284 && (pos->right_child->cost > switchNeighbor->cost))
286 switchNeighbor = pos->right_child;
289 else if ((root->type == GNUNET_CONTAINER_HEAP_ORDER_MIN))
291 if ((pos->left_child != NULL)
292 && (pos->left_child->cost < switchNeighbor->cost))
294 switchNeighbor = pos->left_child;
297 if ((pos->right_child != NULL)
298 && (pos->right_child->cost < switchNeighbor->cost))
300 switchNeighbor = pos->right_child;
304 if (switchNeighbor != pos)
306 swapNodes (switchNeighbor, pos, root);
307 percolateDownHeap (switchNeighbor, root);
314 GNUNET_CONTAINER_heap_remove_node (struct GNUNET_CONTAINER_Heap *root,
318 struct GNUNET_CONTAINER_heap_node *del_node;
319 struct GNUNET_CONTAINER_heap_node *last;
320 GNUNET_CONTAINER_HeapCost old_cost;
323 del_node = find_element (root->root, element);
325 if (del_node == NULL)
327 else if (del_node == root->root)
328 return GNUNET_CONTAINER_heap_remove_root (root);
330 ret = del_node->element;
331 last = getPos (root, root->size);
333 old_cost = del_node->cost;
334 del_node->element = last->element;
335 del_node->cost = last->cost;
337 if (last->parent->left_child == last)
338 last->parent->left_child = NULL;
339 if (last->parent->right_child == last)
340 last->parent->right_child = NULL;
342 if (root->traversal_pos == last)
344 root->traversal_pos = root->root;
349 if (del_node->cost > old_cost)
351 if (root->type == GNUNET_CONTAINER_HEAP_ORDER_MAX)
352 percolateHeap (del_node, root);
353 else if (root->type == GNUNET_CONTAINER_HEAP_ORDER_MIN)
354 percolateDownHeap (del_node, root);
356 else if (del_node->cost < old_cost)
358 if (root->type == GNUNET_CONTAINER_HEAP_ORDER_MAX)
359 percolateDownHeap (del_node, root);
360 else if (root->type == GNUNET_CONTAINER_HEAP_ORDER_MIN)
361 percolateHeap (del_node, root);
368 GNUNET_CONTAINER_heap_insert (struct GNUNET_CONTAINER_Heap *root,
369 void *element, GNUNET_CONTAINER_HeapCost cost)
371 struct GNUNET_CONTAINER_heap_node *new_pos;
375 if (root->max_size > root->size)
377 new_pos = getNextPos (root);
378 new_pos->element = element;
379 new_pos->cost = cost;
382 percolateHeap (new_pos, root);
393 GNUNET_CONTAINER_heap_remove_root (struct GNUNET_CONTAINER_Heap *root)
396 struct GNUNET_CONTAINER_heap_node *root_node;
397 struct GNUNET_CONTAINER_heap_node *last;
399 if ((root == NULL) || (root->size == 0) || (root->root == NULL))
402 root_node = root->root;
403 ret = root_node->element;
404 last = getPos (root, root->size);
406 if ((root_node == last) && (root->size == 1))
408 /* We are removing the last node in the heap! */
410 root->traversal_pos = NULL;
415 if (last->parent->left_child == last)
416 last->parent->left_child = NULL;
417 else if (last->parent->right_child == last)
418 last->parent->right_child = NULL;
420 root_node->element = last->element;
421 root_node->cost = last->cost;
423 if (root->traversal_pos == last)
425 root->traversal_pos = root->root;
430 percolateDownHeap (root->root, root);
435 updatedCost (struct GNUNET_CONTAINER_Heap *root,
436 struct GNUNET_CONTAINER_heap_node *node)
438 struct GNUNET_CONTAINER_heap_node *parent;
441 return GNUNET_SYSERR;
443 parent = node->parent;
445 if ((root->type == GNUNET_CONTAINER_HEAP_ORDER_MAX) && (parent != NULL)
446 && (node->cost > parent->cost))
447 percolateHeap (node, root);
448 else if ((root->type == GNUNET_CONTAINER_HEAP_ORDER_MIN) && (parent != NULL)
449 && (node->cost < parent->cost))
450 percolateHeap (node, root);
451 else if (root->type == GNUNET_CONTAINER_HEAP_ORDER_MAX)
452 percolateDownHeap (node, root);
453 else if (root->type == GNUNET_CONTAINER_HEAP_ORDER_MIN)
454 percolateDownHeap (node, root);
461 GNUNET_CONTAINER_heap_update_cost (struct GNUNET_CONTAINER_Heap *root,
463 GNUNET_CONTAINER_HeapCost new_cost)
465 struct GNUNET_CONTAINER_heap_node *node;
466 int ret = GNUNET_YES;
467 node = find_element (root->root, element);
471 node->cost = new_cost;
472 ret = updatedCost (root, node);
477 internal_iterator (struct GNUNET_CONTAINER_Heap *root,
478 struct GNUNET_CONTAINER_heap_node *node,
479 GNUNET_CONTAINER_HeapIterator iterator, void *cls)
483 internal_iterator (root, node->left_child, iterator, cls);
484 internal_iterator (root, node->right_child, iterator, cls);
485 iterator (cls, node->element, node->cost);
489 GNUNET_CONTAINER_heap_iterate (struct GNUNET_CONTAINER_Heap *heap,
490 GNUNET_CONTAINER_HeapIterator iterator,
493 internal_iterator (heap, heap->root, iterator, cls);
498 GNUNET_CONTAINER_heap_walk_get_next (struct GNUNET_CONTAINER_Heap *root)
503 if ((root->traversal_pos == NULL) && (root->root != NULL))
505 root->traversal_pos = root->root;
508 if (root->traversal_pos == NULL)
511 element = root->traversal_pos->element;
513 choice = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK, 2);
518 root->traversal_pos = root->traversal_pos->right_child;
521 root->traversal_pos = root->traversal_pos->left_child;
530 GNUNET_CONTAINER_heap_get_size (struct GNUNET_CONTAINER_Heap *heap)