Exemple #1
0
Bool SplayFindFirst(Tree *nodeReturn, SplayTree splay,
                    SplayTestNodeFunction testNode,
                    SplayTestTreeFunction testTree,
                    void *closureP, Size closureS)
{
  SplayFindClosureStruct closureStruct;
  Bool found;

  AVER(nodeReturn != NULL);
  AVERT(SplayTree, splay);
  AVER(FUNCHECK(testNode));
  AVER(FUNCHECK(testTree));

  if (SplayTreeIsEmpty(splay) ||
      !testTree(splay, SplayTreeRoot(splay), closureP, closureS))
    return FALSE; /* no suitable nodes in tree */

  closureStruct.p = closureP;
  closureStruct.s = closureS;
  closureStruct.testNode = testNode;
  closureStruct.testTree = testTree;
  closureStruct.splay = splay;
  closureStruct.found = FALSE;

  found = SplaySplay(splay, &closureStruct,
                     SplayFindFirstCompare) == CompareEQUAL &&
          closureStruct.found;

  while (!found) {
    Tree oldRoot, newRoot;
    
    /* FIXME: Rename to "seen" and "not yet seen" or something. */
    oldRoot = SplayTreeRoot(splay);
    newRoot = TreeRight(oldRoot);

    if (newRoot == TreeEMPTY || !(*testTree)(splay, newRoot, closureP, closureS))
      return FALSE; /* no suitable nodes in the rest of the tree */
  
    /* Temporarily chop off the left half-tree, inclusive of root,
       so that the search excludes any nodes we've seen already. */
    SplayTreeSetRoot(splay, newRoot);
    TreeSetRight(oldRoot, TreeEMPTY);

    found = SplaySplay(splay, &closureStruct,
                       SplayFindFirstCompare) == CompareEQUAL &&
            closureStruct.found;

    /* Restore the left tree, then rotate left so that the node we
       just splayed is at the root.  Update both. */
    newRoot = SplayTreeRoot(splay);
    TreeSetRight(oldRoot, newRoot);
    SplayTreeSetRoot(splay, oldRoot);
    TreeRotateLeft(&splay->root);
    splay->updateNode(splay, oldRoot);
    splay->updateNode(splay, newRoot);
  }

  *nodeReturn = SplayTreeRoot(splay);
  return TRUE;
}
Exemple #2
0
void TreeBalance(Tree *treeIO)
{
  Count depth;

  AVER(treeIO != NULL);
  AVERT(Tree, *treeIO);

  depth = TreeToVine(treeIO);

  if (depth > 2) {
    Count n = depth - 1;
    do {
      Count m = n / 2, i;
      Tree *link = treeIO;
      for (i = 0; i < m; ++i) {
        TreeRotateLeft(link);
        link = &((*link)->right);
      }
      n = n - m - 1;
    } while (n > 1);
  }
}