GNUnet  0.10.x
Data Structures | Macros | Functions
container_heap.c File Reference

Implementation of a heap. More...

#include "platform.h"
#include "gnunet_container_lib.h"
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Data Structures

struct  GNUNET_CONTAINER_HeapNode
 Node in the heap. More...
 
struct  GNUNET_CONTAINER_Heap
 Handle to a node in a heap. More...
 

Macros

#define LOG(kind, ...)   GNUNET_log_from (kind, "util-container-heap", __VA_ARGS__)
 
#define EXTRA_CHECKS   0
 
#define CHECK(n)   do {} while (0)
 

Functions

struct GNUNET_CONTAINER_HeapGNUNET_CONTAINER_heap_create (enum GNUNET_CONTAINER_HeapOrder order)
 Create a new heap. More...
 
void GNUNET_CONTAINER_heap_destroy (struct GNUNET_CONTAINER_Heap *heap)
 Destroys the heap. More...
 
void * GNUNET_CONTAINER_heap_peek (const struct GNUNET_CONTAINER_Heap *heap)
 Get element stored at the root of heap. More...
 
int GNUNET_CONTAINER_heap_peek2 (const struct GNUNET_CONTAINER_Heap *heap, void **element, GNUNET_CONTAINER_HeapCostType *cost)
 Get element and cost stored at the root of heap. More...
 
unsigned int GNUNET_CONTAINER_heap_get_size (const struct GNUNET_CONTAINER_Heap *heap)
 Get the current size of the heap. More...
 
GNUNET_CONTAINER_HeapCostType GNUNET_CONTAINER_heap_node_get_cost (const struct GNUNET_CONTAINER_HeapNode *node)
 Get the current cost of the node. More...
 
static int node_iterator (const struct GNUNET_CONTAINER_Heap *heap, struct GNUNET_CONTAINER_HeapNode *node, GNUNET_CONTAINER_HeapIterator iterator, void *iterator_cls)
 Iterate over the children of the given node. More...
 
void GNUNET_CONTAINER_heap_iterate (const struct GNUNET_CONTAINER_Heap *heap, GNUNET_CONTAINER_HeapIterator iterator, void *iterator_cls)
 Iterate over all entries in the heap. More...
 
void * GNUNET_CONTAINER_heap_walk_get_next (struct GNUNET_CONTAINER_Heap *heap)
 Perform a random walk of the tree. More...
 
static void insert_node (struct GNUNET_CONTAINER_Heap *heap, struct GNUNET_CONTAINER_HeapNode *pos, struct GNUNET_CONTAINER_HeapNode *node)
 Insert the given node 'node' into the subtree starting at 'pos' (while keeping the tree somewhat balanced). More...
 
struct GNUNET_CONTAINER_HeapNodeGNUNET_CONTAINER_heap_insert (struct GNUNET_CONTAINER_Heap *heap, void *element, GNUNET_CONTAINER_HeapCostType cost)
 Inserts a new element into the heap. More...
 
void * GNUNET_CONTAINER_heap_remove_root (struct GNUNET_CONTAINER_Heap *heap)
 Remove root of the heap. More...
 
static void remove_node (struct GNUNET_CONTAINER_HeapNode *node)
 Remove the given node 'node' from the tree and update the 'tree_size' fields accordingly. More...
 
void * GNUNET_CONTAINER_heap_remove_node (struct GNUNET_CONTAINER_HeapNode *node)
 Removes a node from the heap. More...
 
void GNUNET_CONTAINER_heap_update_cost (struct GNUNET_CONTAINER_HeapNode *node, GNUNET_CONTAINER_HeapCostType new_cost)
 Updates the cost of any node in the tree. More...
 

Detailed Description

Implementation of a heap.

Author
Nathan Evans
Christian Grothoff

Definition in file container_heap.c.

Macro Definition Documentation

◆ LOG

#define LOG (   kind,
  ... 
)    GNUNET_log_from (kind, "util-container-heap", __VA_ARGS__)

Definition at line 31 of file container_heap.c.

◆ EXTRA_CHECKS

#define EXTRA_CHECKS   0

Definition at line 33 of file container_heap.c.

◆ CHECK

#define CHECK (   n)    do {} while (0)

Function Documentation

◆ GNUNET_CONTAINER_heap_peek2()

int GNUNET_CONTAINER_heap_peek2 ( const struct GNUNET_CONTAINER_Heap heap,
void **  element,
GNUNET_CONTAINER_HeapCostType cost 
)

Get element and cost stored at the root of heap.

Parameters
[in]heapHeap to inspect.
[out]elementRoot element is returned here.
[out]costCost of element is returned here.
Returns
GNUNET_YES if an element is returned, GNUNET_NO if the heap is empty.

Definition at line 190 of file container_heap.c.

References GNUNET_CONTAINER_HeapNode::cost, GNUNET_CONTAINER_HeapNode::element, GNUNET_NO, GNUNET_YES, and GNUNET_CONTAINER_Heap::root.

Referenced by GCP_attach_path().

193 {
194  if (NULL == heap->root)
195  return GNUNET_NO;
196  if (NULL != element)
197  *element = heap->root->element;
198  if (NULL != cost)
199  *cost = heap->root->cost;
200  return GNUNET_YES;
201 }
GNUNET_CONTAINER_HeapCostType cost
Cost for this element.
#define GNUNET_NO
Definition: gnunet_common.h:81
void * element
Our element.
#define GNUNET_YES
Definition: gnunet_common.h:80
struct GNUNET_CONTAINER_HeapNode * root
Root of the heap.
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◆ node_iterator()

static int node_iterator ( const struct GNUNET_CONTAINER_Heap heap,
struct GNUNET_CONTAINER_HeapNode node,
GNUNET_CONTAINER_HeapIterator  iterator,
void *  iterator_cls 
)
static

Iterate over the children of the given node.

Parameters
heapargument to give to iterator
nodenode to iterate over
iteratorfunction to call on each node
iterator_clsclosure for iterator
Returns
GNUNET_YES to continue to iterate

Definition at line 241 of file container_heap.c.

References GNUNET_CONTAINER_HeapNode::cost, GNUNET_CONTAINER_HeapNode::element, GNUNET_NO, GNUNET_YES, iterator(), GNUNET_CONTAINER_HeapNode::left_child, and GNUNET_CONTAINER_HeapNode::right_child.

Referenced by GNUNET_CONTAINER_heap_iterate().

244 {
245  if (node == NULL)
246  return GNUNET_YES;
247  if (GNUNET_YES !=
248  node_iterator (heap, node->left_child, iterator, iterator_cls))
249  return GNUNET_NO;
250  if (GNUNET_YES !=
251  node_iterator (heap, node->right_child, iterator, iterator_cls))
252  return GNUNET_NO;
253  return iterator (iterator_cls, node, node->element, node->cost);
254 }
static int iterator(void *cls, const struct GNUNET_PeerIdentity *key, void *value)
Iterator over hash map entries.
struct GNUNET_CONTAINER_HeapNode * left_child
Left child.
GNUNET_CONTAINER_HeapCostType cost
Cost for this element.
#define GNUNET_NO
Definition: gnunet_common.h:81
static int node_iterator(const struct GNUNET_CONTAINER_Heap *heap, struct GNUNET_CONTAINER_HeapNode *node, GNUNET_CONTAINER_HeapIterator iterator, void *iterator_cls)
Iterate over the children of the given node.
void * element
Our element.
#define GNUNET_YES
Definition: gnunet_common.h:80
struct GNUNET_CONTAINER_HeapNode * right_child
Right child.
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◆ insert_node()

static void insert_node ( struct GNUNET_CONTAINER_Heap heap,
struct GNUNET_CONTAINER_HeapNode pos,
struct GNUNET_CONTAINER_HeapNode node 
)
static

Insert the given node 'node' into the subtree starting at 'pos' (while keeping the tree somewhat balanced).

Parameters
heapheap to modify
posexisting tree
nodenode to insert (which may be a subtree itself)

Definition at line 313 of file container_heap.c.

References CHECK, GNUNET_CONTAINER_HeapNode::cost, GNUNET_assert, GNUNET_CONTAINER_HEAP_ORDER_MAX, GNUNET_CONTAINER_HeapNode::left_child, GNUNET_CONTAINER_Heap::order, GNUNET_CONTAINER_HeapNode::parent, GNUNET_CONTAINER_HeapNode::right_child, GNUNET_CONTAINER_Heap::root, and GNUNET_CONTAINER_HeapNode::tree_size.

Referenced by GNUNET_CONTAINER_heap_insert(), GNUNET_CONTAINER_heap_remove_root(), GNUNET_CONTAINER_heap_update_cost(), and remove_node().

316 {
318 
319  GNUNET_assert (node->parent == NULL);
320  while ((heap->order == GNUNET_CONTAINER_HEAP_ORDER_MAX) ? (pos->cost >=
321  node->cost)
322  : (pos->cost <= node->cost))
323  {
324  /* node is descendent of pos */
325  pos->tree_size += (1 + node->tree_size);
326  if (pos->left_child == NULL)
327  {
328  pos->left_child = node;
329  node->parent = pos;
330  return;
331  }
332  if (pos->right_child == NULL)
333  {
334  pos->right_child = node;
335  node->parent = pos;
336  return;
337  }
338  /* keep it balanced by descending into smaller subtree */
339  if (pos->left_child->tree_size < pos->right_child->tree_size)
340  pos = pos->left_child;
341  else
342  pos = pos->right_child;
343  }
344  /* make 'node' parent of 'pos' */
345  parent = pos->parent;
346  pos->parent = NULL;
347  node->parent = parent;
348  if (NULL == parent)
349  {
350  heap->root = node;
351  }
352  else
353  {
354  if (parent->left_child == pos)
355  parent->left_child = node;
356  else
357  parent->right_child = node;
358  }
359  /* insert 'pos' below 'node' */
360  insert_node (heap, node, pos);
361  CHECK (pos);
362 }
struct GNUNET_CONTAINER_HeapNode * left_child
Left child.
#define CHECK(n)
static void insert_node(struct GNUNET_CONTAINER_Heap *heap, struct GNUNET_CONTAINER_HeapNode *pos, struct GNUNET_CONTAINER_HeapNode *node)
Insert the given node &#39;node&#39; into the subtree starting at &#39;pos&#39; (while keeping the tree somewhat bala...
#define GNUNET_assert(cond)
Use this for fatal errors that cannot be handled.
GNUNET_CONTAINER_HeapCostType cost
Cost for this element.
unsigned int tree_size
Number of elements below this node in the heap (excluding this node itself).
Node in the heap.
enum GNUNET_CONTAINER_HeapOrder order
How is the heap sorted?
struct GNUNET_CONTAINER_HeapNode * parent
Parent node.
Heap with the maximum cost at the root.
struct GNUNET_CONTAINER_HeapNode * root
Root of the heap.
struct GNUNET_CONTAINER_HeapNode * right_child
Right child.
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◆ remove_node()

static void remove_node ( struct GNUNET_CONTAINER_HeapNode node)
static

Remove the given node 'node' from the tree and update the 'tree_size' fields accordingly.

Preserves the children of 'node' and does NOT change the overall 'size' field of the tree.

Definition at line 447 of file container_heap.c.

References CHECK, GNUNET_assert, GNUNET_CONTAINER_HeapNode::heap, insert_node(), GNUNET_CONTAINER_HeapNode::left_child, GNUNET_CONTAINER_HeapNode::parent, GNUNET_CONTAINER_HeapNode::right_child, GNUNET_CONTAINER_Heap::root, and GNUNET_CONTAINER_HeapNode::tree_size.

Referenced by GNUNET_CONTAINER_heap_remove_node(), and GNUNET_CONTAINER_heap_update_cost().

448 {
449  struct GNUNET_CONTAINER_HeapNode *ancestor;
450  struct GNUNET_CONTAINER_Heap *heap = node->heap;
451 
452  /* update 'size' of the ancestors */
453  ancestor = node;
454  while (NULL != (ancestor = ancestor->parent))
455  ancestor->tree_size--;
456 
457  /* update 'size' of node itself */
458  if (node->left_child != NULL)
459  node->tree_size -= (1 + node->left_child->tree_size);
460  if (node->right_child != NULL)
461  node->tree_size -= (1 + node->right_child->tree_size);
462 
463  /* unlink 'node' itself and insert children in its place */
464  if (node->parent == NULL)
465  {
466  if (node->left_child != NULL)
467  {
468  heap->root = node->left_child;
469  node->left_child->parent = NULL;
470  if (node->right_child != NULL)
471  {
472  node->right_child->parent = NULL;
473  insert_node (heap, heap->root, node->right_child);
474  }
475  }
476  else
477  {
478  heap->root = node->right_child;
479  if (node->right_child != NULL)
480  node->right_child->parent = NULL;
481  }
482  }
483  else
484  {
485  if (node->parent->left_child == node)
486  node->parent->left_child = NULL;
487  else
488  node->parent->right_child = NULL;
489  if (node->left_child != NULL)
490  {
491  node->left_child->parent = NULL;
492  node->parent->tree_size -= (1 + node->left_child->tree_size);
493  insert_node (heap, node->parent, node->left_child);
494  }
495  if (node->right_child != NULL)
496  {
497  node->right_child->parent = NULL;
498  node->parent->tree_size -= (1 + node->right_child->tree_size);
499  insert_node (heap, node->parent, node->right_child);
500  }
501  }
502  node->parent = NULL;
503  node->left_child = NULL;
504  node->right_child = NULL;
505  GNUNET_assert (node->tree_size == 0);
506  CHECK (heap->root);
507 }
struct GNUNET_CONTAINER_HeapNode * left_child
Left child.
#define CHECK(n)
static void insert_node(struct GNUNET_CONTAINER_Heap *heap, struct GNUNET_CONTAINER_HeapNode *pos, struct GNUNET_CONTAINER_HeapNode *node)
Insert the given node &#39;node&#39; into the subtree starting at &#39;pos&#39; (while keeping the tree somewhat bala...
#define GNUNET_assert(cond)
Use this for fatal errors that cannot be handled.
Handle to a node in a heap.
unsigned int tree_size
Number of elements below this node in the heap (excluding this node itself).
Node in the heap.
struct GNUNET_CONTAINER_Heap * heap
Heap this node belongs to.
struct GNUNET_CONTAINER_HeapNode * parent
Parent node.
struct GNUNET_CONTAINER_HeapNode * root
Root of the heap.
struct GNUNET_CONTAINER_HeapNode * right_child
Right child.
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