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;
76 internal_print (struct GNUNET_CONTAINER_heap_node *root)
78 fprintf (stdout, "%d\n", root->cost);
79 if (root->left_child != NULL)
81 fprintf (stdout, "LEFT of %d\n", root->cost);
82 internal_print (root->left_child);
84 if (root->right_child != NULL)
86 fprintf (stdout, "RIGHT of %d\n", root->cost);
87 internal_print (root->right_child);
92 printTree (struct GNUNET_CONTAINER_Heap *root)
94 internal_print (root->root);
97 struct GNUNET_CONTAINER_Heap *
98 GNUNET_CONTAINER_heap_create (enum GNUNET_CONTAINER_HeapOrder type)
100 struct GNUNET_CONTAINER_Heap *heap;
101 heap = malloc (sizeof (struct GNUNET_CONTAINER_Heap));
105 heap->traversal_pos = NULL;
112 GNUNET_CONTAINER_heap_destroy (struct GNUNET_CONTAINER_Heap *heap)
115 while (heap->size > 0)
117 unused = GNUNET_CONTAINER_heap_remove_root (heap);
124 struct GNUNET_CONTAINER_heap_node *
125 find_element (struct GNUNET_CONTAINER_heap_node *node, void *element)
127 struct GNUNET_CONTAINER_heap_node *ret;
129 if ((node != NULL) && (node->element == element))
134 if ((ret == NULL) && (node->left_child != NULL))
136 ret = find_element (node->left_child, element);
139 if ((ret == NULL) && (node->right_child != NULL))
141 ret = find_element (node->right_child, element);
147 static struct GNUNET_CONTAINER_heap_node *
148 getNextPos (struct GNUNET_CONTAINER_Heap *root)
150 struct GNUNET_CONTAINER_heap_node *ret;
151 struct GNUNET_CONTAINER_heap_node *parent;
156 ret = GNUNET_malloc (sizeof (struct GNUNET_CONTAINER_heap_node));
157 pos = root->size + 1;
158 depth = (int) log2 (pos);
159 ret->left_child = NULL;
160 ret->right_child = NULL;
170 for (i = depth; i > 1; i--)
172 if (((pos / (1 << (i - 1))) % 2) == 0)
173 parent = parent->left_child;
175 parent = parent->right_child;
178 ret->parent = parent;
180 parent->left_child = ret;
182 parent->right_child = ret;
190 static struct GNUNET_CONTAINER_heap_node *
191 getPos (struct GNUNET_CONTAINER_Heap *root, unsigned int pos)
193 struct GNUNET_CONTAINER_heap_node *ret;
198 depth = (int) log2 (pos);
200 if (pos > root->size)
207 for (i = depth; i > 0; i--)
209 if (((pos / (1 << (i - 1))) % 2) == 0)
210 ret = ret->left_child;
212 ret = ret->right_child;
221 swapNodes (struct GNUNET_CONTAINER_heap_node *first,
222 struct GNUNET_CONTAINER_heap_node *second,
223 struct GNUNET_CONTAINER_Heap *root)
226 GNUNET_CONTAINER_HeapCost temp_cost;
228 temp_element = first->element;
229 temp_cost = first->cost;
230 first->element = second->element;
231 first->cost = second->cost;
232 second->element = temp_element;
233 second->cost = temp_cost;
236 * I still worry that there is some good reason for
237 * elements being location aware... but it eludes me
239 if ((root->type == GNUNET_DV_MAX_HEAP))
241 first->neighbor->max_loc = first;
242 second->neighbor->max_loc = second;
244 else if ((root->type == GNUNET_DV_MIN_HEAP))
246 first->neighbor->min_loc = first;
247 second->neighbor->min_loc = second;
254 percolateHeap (struct GNUNET_CONTAINER_heap_node *pos,
255 struct GNUNET_CONTAINER_Heap *root)
258 while ((pos->parent != NULL) &&
259 (((root->type == GNUNET_CONTAINER_HEAP_ORDER_MAX)
260 && (pos->parent->cost < pos->cost))
261 || ((root->type == GNUNET_CONTAINER_HEAP_ORDER_MIN)
262 && (pos->parent->cost > pos->cost))))
264 swapNodes (pos, pos->parent, root);
274 percolateDownHeap (struct GNUNET_CONTAINER_heap_node *pos,
275 struct GNUNET_CONTAINER_Heap *root)
277 struct GNUNET_CONTAINER_heap_node *switchNeighbor;
279 switchNeighbor = pos;
281 if ((root->type == GNUNET_CONTAINER_HEAP_ORDER_MAX))
283 if ((pos->left_child != NULL)
284 && (pos->left_child->cost > switchNeighbor->cost))
286 switchNeighbor = pos->left_child;
289 if ((pos->right_child != NULL)
290 && (pos->right_child->cost > switchNeighbor->cost))
292 switchNeighbor = pos->right_child;
295 else if ((root->type == GNUNET_CONTAINER_HEAP_ORDER_MIN))
297 if ((pos->left_child != NULL)
298 && (pos->left_child->cost < switchNeighbor->cost))
300 switchNeighbor = pos->left_child;
303 if ((pos->right_child != NULL)
304 && (pos->right_child->cost < switchNeighbor->cost))
306 switchNeighbor = pos->right_child;
310 if (switchNeighbor != pos)
312 swapNodes (switchNeighbor, pos, root);
313 percolateDownHeap (switchNeighbor, root);
320 GNUNET_CONTAINER_heap_remove_node (struct GNUNET_CONTAINER_Heap *root,
324 struct GNUNET_CONTAINER_heap_node *del_node;
325 struct GNUNET_CONTAINER_heap_node *last;
326 GNUNET_CONTAINER_HeapCost old_cost;
329 del_node = find_element (root->root, element);
331 if (del_node == NULL)
333 else if (del_node == root->root)
334 return GNUNET_CONTAINER_heap_remove_root (root);
336 ret = del_node->element;
337 last = getPos (root, root->size);
339 old_cost = del_node->cost;
340 del_node->element = last->element;
341 del_node->cost = last->cost;
343 if (last->parent->left_child == last)
344 last->parent->left_child = NULL;
345 if (last->parent->right_child == last)
346 last->parent->right_child = NULL;
348 if (root->traversal_pos == last)
350 root->traversal_pos = root->root;
355 if (del_node->cost > old_cost)
357 if (root->type == GNUNET_CONTAINER_HEAP_ORDER_MAX)
358 percolateHeap (del_node, root);
359 else if (root->type == GNUNET_CONTAINER_HEAP_ORDER_MIN)
360 percolateDownHeap (del_node, root);
362 else if (del_node->cost < old_cost)
364 if (root->type == GNUNET_CONTAINER_HEAP_ORDER_MAX)
365 percolateDownHeap (del_node, root);
366 else if (root->type == GNUNET_CONTAINER_HEAP_ORDER_MIN)
367 percolateHeap (del_node, root);
374 GNUNET_CONTAINER_heap_insert (struct GNUNET_CONTAINER_Heap *root,
375 void *element, GNUNET_CONTAINER_HeapCost cost)
377 struct GNUNET_CONTAINER_heap_node *new_pos;
381 if (root->max_size > root->size)
383 new_pos = getNextPos (root);
384 new_pos->element = element;
385 new_pos->cost = cost;
387 /*We no longer can tolerate pointers between heaps :( */
388 /*if (root->type == GNUNET_DV_MIN_HEAP)
389 new_pos->neighbor->min_loc = new_pos;
390 else if (root->type == GNUNET_DV_MAX_HEAP)
391 new_pos->neighbor->max_loc = new_pos; */
393 percolateHeap (new_pos, root);
404 GNUNET_CONTAINER_heap_remove_root (struct GNUNET_CONTAINER_Heap *root)
407 struct GNUNET_CONTAINER_heap_node *root_node;
408 struct GNUNET_CONTAINER_heap_node *last;
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;
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)