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;
91 next_power_of_2(int v)
104 internal_print (struct GNUNET_CONTAINER_heap_node *root)
106 fprintf (stdout, "%llu\n", (unsigned long long) root->cost);
107 if (root->left_child != NULL)
109 fprintf (stdout, "LEFT of %llu\n", (unsigned long long) root->cost);
110 internal_print (root->left_child);
112 if (root->right_child != NULL)
114 fprintf (stdout, "RIGHT of %llu\n", (unsigned long long) root->cost);
115 internal_print (root->right_child);
120 printTree (struct GNUNET_CONTAINER_Heap *root)
122 internal_print (root->root);
126 struct GNUNET_CONTAINER_Heap *
127 GNUNET_CONTAINER_heap_create (enum GNUNET_CONTAINER_HeapOrder type)
129 struct GNUNET_CONTAINER_Heap *heap;
130 heap = malloc (sizeof (struct GNUNET_CONTAINER_Heap));
134 heap->traversal_pos = NULL;
141 GNUNET_CONTAINER_heap_destroy (struct GNUNET_CONTAINER_Heap *heap)
143 while (heap->size > 0)
144 GNUNET_CONTAINER_heap_remove_root (heap);
149 struct GNUNET_CONTAINER_heap_node *
150 find_element (struct GNUNET_CONTAINER_heap_node *node, void *element)
152 struct GNUNET_CONTAINER_heap_node *ret;
157 if (node->element == element)
160 if (node->left_child != NULL)
161 ret = find_element (node->left_child, element);
163 if ((ret == NULL) && (node->right_child != NULL))
164 ret = find_element (node->right_child, element);
169 static struct GNUNET_CONTAINER_heap_node *
170 getNextPos (struct GNUNET_CONTAINER_Heap *root)
172 struct GNUNET_CONTAINER_heap_node *ret;
173 struct GNUNET_CONTAINER_heap_node *parent;
177 ret = GNUNET_malloc (sizeof (struct GNUNET_CONTAINER_heap_node));
178 pos = root->size + 1;
179 ret->left_child = NULL;
180 ret->right_child = NULL;
190 for (i = next_power_of_2(pos) >> 2; i > 1; i >>= 1)
192 if (((pos / i) % 2) == 0)
193 parent = parent->left_child;
195 parent = parent->right_child;
198 ret->parent = parent;
200 parent->left_child = ret;
202 parent->right_child = ret;
210 static struct GNUNET_CONTAINER_heap_node *
211 getPos (struct GNUNET_CONTAINER_Heap *root, unsigned int pos)
213 struct GNUNET_CONTAINER_heap_node *ret;
217 if (pos > root->size)
224 for (i = next_power_of_2(pos) >> 2; i > 0; i >>= 1)
226 if (((pos / i) % 2) == 0)
227 ret = ret->left_child;
229 ret = ret->right_child;
238 swapNodes (struct GNUNET_CONTAINER_heap_node *first,
239 struct GNUNET_CONTAINER_heap_node *second,
240 struct GNUNET_CONTAINER_Heap *root)
243 GNUNET_CONTAINER_HeapCost temp_cost;
245 temp_element = first->element;
246 temp_cost = first->cost;
247 first->element = second->element;
248 first->cost = second->cost;
249 second->element = temp_element;
250 second->cost = temp_cost;
256 percolateHeap (struct GNUNET_CONTAINER_heap_node *pos,
257 struct GNUNET_CONTAINER_Heap *root)
260 while ((pos->parent != NULL) &&
261 (((root->type == GNUNET_CONTAINER_HEAP_ORDER_MAX)
262 && (pos->parent->cost < pos->cost))
263 || ((root->type == GNUNET_CONTAINER_HEAP_ORDER_MIN)
264 && (pos->parent->cost > pos->cost))))
266 swapNodes (pos, pos->parent, root);
276 percolateDownHeap (struct GNUNET_CONTAINER_heap_node *pos,
277 struct GNUNET_CONTAINER_Heap *root)
279 struct GNUNET_CONTAINER_heap_node *switchNeighbor;
281 switchNeighbor = pos;
283 if ((root->type == GNUNET_CONTAINER_HEAP_ORDER_MAX))
285 if ((pos->left_child != NULL)
286 && (pos->left_child->cost > switchNeighbor->cost))
288 switchNeighbor = pos->left_child;
291 if ((pos->right_child != NULL)
292 && (pos->right_child->cost > switchNeighbor->cost))
294 switchNeighbor = pos->right_child;
297 else if ((root->type == GNUNET_CONTAINER_HEAP_ORDER_MIN))
299 if ((pos->left_child != NULL)
300 && (pos->left_child->cost < switchNeighbor->cost))
302 switchNeighbor = pos->left_child;
305 if ((pos->right_child != NULL)
306 && (pos->right_child->cost < switchNeighbor->cost))
308 switchNeighbor = pos->right_child;
312 if (switchNeighbor != pos)
314 swapNodes (switchNeighbor, pos, root);
315 percolateDownHeap (switchNeighbor, root);
322 GNUNET_CONTAINER_heap_remove_node (struct GNUNET_CONTAINER_Heap *root,
326 struct GNUNET_CONTAINER_heap_node *del_node;
327 struct GNUNET_CONTAINER_heap_node *last;
328 GNUNET_CONTAINER_HeapCost old_cost;
331 del_node = find_element (root->root, element);
333 if (del_node == NULL)
335 else if (del_node == root->root)
336 return GNUNET_CONTAINER_heap_remove_root (root);
338 ret = del_node->element;
339 last = getPos (root, root->size);
341 old_cost = del_node->cost;
342 del_node->element = last->element;
343 del_node->cost = last->cost;
345 if (last->parent->left_child == last)
346 last->parent->left_child = NULL;
347 if (last->parent->right_child == last)
348 last->parent->right_child = NULL;
350 if (root->traversal_pos == last)
352 root->traversal_pos = root->root;
357 if (del_node->cost > old_cost)
359 if (root->type == GNUNET_CONTAINER_HEAP_ORDER_MAX)
360 percolateHeap (del_node, root);
361 else if (root->type == GNUNET_CONTAINER_HEAP_ORDER_MIN)
362 percolateDownHeap (del_node, root);
364 else if (del_node->cost < old_cost)
366 if (root->type == GNUNET_CONTAINER_HEAP_ORDER_MAX)
367 percolateDownHeap (del_node, root);
368 else if (root->type == GNUNET_CONTAINER_HEAP_ORDER_MIN)
369 percolateHeap (del_node, root);
376 GNUNET_CONTAINER_heap_insert (struct GNUNET_CONTAINER_Heap *root,
377 void *element, GNUNET_CONTAINER_HeapCost cost)
379 struct GNUNET_CONTAINER_heap_node *new_pos;
383 if (root->max_size > root->size)
385 new_pos = getNextPos (root);
386 new_pos->element = element;
387 new_pos->cost = cost;
390 percolateHeap (new_pos, root);
401 GNUNET_CONTAINER_heap_remove_root (struct GNUNET_CONTAINER_Heap *root)
404 struct GNUNET_CONTAINER_heap_node *root_node;
405 struct GNUNET_CONTAINER_heap_node *last;
407 if ((root == NULL) || (root->size == 0) || (root->root == NULL))
410 root_node = root->root;
411 ret = root_node->element;
412 last = getPos (root, root->size);
414 if ((root_node == last) && (root->size == 1))
416 /* We are removing the last node in the heap! */
418 root->traversal_pos = NULL;
419 GNUNET_assert (0 == --root->size);
423 if (last->parent->left_child == last)
424 last->parent->left_child = NULL;
425 else if (last->parent->right_child == last)
426 last->parent->right_child = NULL;
428 root_node->element = last->element;
429 root_node->cost = last->cost;
431 if (root->traversal_pos == last)
433 root->traversal_pos = root->root;
438 percolateDownHeap (root->root, root);
443 updatedCost (struct GNUNET_CONTAINER_Heap *root,
444 struct GNUNET_CONTAINER_heap_node *node)
446 struct GNUNET_CONTAINER_heap_node *parent;
449 return GNUNET_SYSERR;
451 parent = node->parent;
453 if ((root->type == GNUNET_CONTAINER_HEAP_ORDER_MAX) && (parent != NULL)
454 && (node->cost > parent->cost))
455 percolateHeap (node, root);
456 else if ((root->type == GNUNET_CONTAINER_HEAP_ORDER_MIN) && (parent != NULL)
457 && (node->cost < parent->cost))
458 percolateHeap (node, root);
459 else if (root->type == GNUNET_CONTAINER_HEAP_ORDER_MAX)
460 percolateDownHeap (node, root);
461 else if (root->type == GNUNET_CONTAINER_HEAP_ORDER_MIN)
462 percolateDownHeap (node, root);
469 GNUNET_CONTAINER_heap_update_cost (struct GNUNET_CONTAINER_Heap *root,
471 GNUNET_CONTAINER_HeapCost new_cost)
473 struct GNUNET_CONTAINER_heap_node *node;
474 int ret = GNUNET_YES;
475 node = find_element (root->root, element);
479 node->cost = new_cost;
480 ret = updatedCost (root, node);
485 internal_iterator (struct GNUNET_CONTAINER_Heap *root,
486 struct GNUNET_CONTAINER_heap_node *node,
487 GNUNET_CONTAINER_HeapIterator iterator, void *cls)
491 internal_iterator (root, node->left_child, iterator, cls);
492 internal_iterator (root, node->right_child, iterator, cls);
493 iterator (cls, node->element, node->cost);
497 GNUNET_CONTAINER_heap_iterate (struct GNUNET_CONTAINER_Heap *heap,
498 GNUNET_CONTAINER_HeapIterator iterator,
501 internal_iterator (heap, heap->root, iterator, cls);
506 GNUNET_CONTAINER_heap_walk_get_next (struct GNUNET_CONTAINER_Heap *root)
511 if ((root->traversal_pos == NULL) && (root->root != NULL))
513 root->traversal_pos = root->root;
516 if (root->traversal_pos == NULL)
519 element = root->traversal_pos->element;
521 choice = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK, 2);
526 root->traversal_pos = root->traversal_pos->right_child;
529 root->traversal_pos = root->traversal_pos->left_child;
538 GNUNET_CONTAINER_heap_get_size (struct GNUNET_CONTAINER_Heap *heap)