C++ SplayTree::updateNode方法代码示例

static Tree SplayTreeSuccessor(SplayTree splay)
{
  Tree oldRoot, newRoot;

  AVERT(SplayTree, splay);
  AVER(!SplayTreeIsEmpty(splay));

  oldRoot = SplayTreeRoot(splay);

  if (!TreeHasRight(oldRoot))
    return TreeEMPTY; /* No successor */

  /* temporarily chop off the left half-tree, inclusive of root */
  SplayTreeSetRoot(splay, TreeRight(oldRoot));
  TreeSetRight(oldRoot, TreeEMPTY);
  (void)SplaySplay(splay, NULL, compareLess);
  newRoot = SplayTreeRoot(splay);
  AVER(newRoot != TreeEMPTY);
  AVER(TreeLeft(newRoot) == TreeEMPTY);
  TreeSetLeft(newRoot, oldRoot);
  splay->updateNode(splay, oldRoot);
  splay->updateNode(splay, newRoot);

  return newRoot;
}

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;
}

void SplayNodeInit(SplayTree splay, Tree node)
{
  AVERT(SplayTree, splay);
  AVERT(Tree, node);
  AVER(!TreeHasLeft(node)); /* otherwise, call SplayNodeRefresh */
  AVER(!TreeHasRight(node)); /* otherwise, call SplayNodeRefresh */

  splay->updateNode(splay, node);
}

Bool SplayFindLast(Tree *nodeReturn, SplayTree splay,
                   SplayTestNodeFunction testNode,
                   SplayTestTreeFunction testTree,
                   void *testClosure)
{
  SplayFindClosureStruct closureStruct;
  Bool found;

  AVER_CRITICAL(nodeReturn != NULL);
  AVERT_CRITICAL(SplayTree, splay);
  AVER_CRITICAL(FUNCHECK(testNode));
  AVER_CRITICAL(FUNCHECK(testTree));

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

  closureStruct.testClosure = testClosure;
  closureStruct.testNode = testNode;
  closureStruct.testTree = testTree;
  closureStruct.splay = splay;

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

  while (!found) {
    Tree oldRoot, newRoot;
    
    oldRoot = SplayTreeRoot(splay);
    newRoot = TreeLeft(oldRoot);

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

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

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

  *nodeReturn = SplayTreeRoot(splay);
  return TRUE;
}

void SplayDebugUpdate(SplayTree splay, Tree tree)
{
  AVERT(SplayTree, splay);
  AVERT(Tree, tree);
  if (tree == TreeEMPTY)
    return;
  SplayDebugUpdate(splay, TreeLeft(tree));
  SplayDebugUpdate(splay, TreeRight(tree));
  splay->updateNode(splay, tree);
}

Bool SplayTreeInsert(SplayTree splay, Tree node)
{
  Tree neighbour;

  AVERT(SplayTree, splay);
  AVERT(Tree, node);
  AVER(TreeLeft(node) == TreeEMPTY);
  AVER(TreeRight(node) == TreeEMPTY);

  if (SplayTreeIsEmpty(splay)) {
    SplayTreeSetRoot(splay, node);
    return TRUE;
  }
  
  switch (SplaySplay(splay, splay->nodeKey(node), splay->compare)) {
  default:
    NOTREACHED;
    /* fall through */
  case CompareEQUAL: /* duplicate node */
    return FALSE;
    
  case CompareGREATER: /* left neighbour is at root */
    neighbour = SplayTreeRoot(splay);
    SplayTreeSetRoot(splay, node);
    TreeSetRight(node, TreeRight(neighbour));
    TreeSetLeft(node, neighbour);
    TreeSetRight(neighbour, TreeEMPTY);
    break;

  case CompareLESS: /* right neighbour is at root */
    neighbour = SplayTreeRoot(splay);
    SplayTreeSetRoot(splay, node);
    TreeSetLeft(node, TreeLeft(neighbour));
    TreeSetRight(node, neighbour);
    TreeSetLeft(neighbour, TreeEMPTY);
    break;
  }

  splay->updateNode(splay, neighbour);
  splay->updateNode(splay, node);
  return TRUE;
}

static Tree SplayUpdateRightSpine(SplayTree splay, Tree node, Tree child)
{
  AVERT_CRITICAL(SplayTree, splay);
  AVERT_CRITICAL(Tree, node);
  AVERT_CRITICAL(Tree, child);
  while (node != TreeEMPTY) {
    Tree parent = TreeRight(node);
    TreeSetRight(node, child); /* un-reverse pointer */
    splay->updateNode(splay, node);
    child = node;
    node = parent;
  }
  return child;
}

void SplayNodeRefresh(SplayTree splay, Tree node)
{
  Compare cmp;

  AVERT(SplayTree, splay);
  AVERT(Tree, node);
  AVER(!SplayTreeIsEmpty(splay)); /* must contain node, at least */

  cmp = SplaySplay(splay, splay->nodeKey(node), splay->compare);
  AVER(cmp == CompareEQUAL);
  AVER(SplayTreeRoot(splay) == node);

  splay->updateNode(splay, node);
}

static void SplayAssembleRev(SplayTree splay, SplayState state)
{
  Tree left, right;

  AVERT(SplayTree, splay);
  AVER(state->middle != TreeEMPTY);
  
  left = TreeLeft(state->middle);
  left = SplayUpdateRightSpine(splay, state->leftLast, left);
  TreeSetLeft(state->middle, left);

  right = TreeRight(state->middle);
  right = SplayUpdateLeftSpine(splay, state->rightFirst, right);
  TreeSetRight(state->middle, right);

  splay->updateNode(splay, state->middle);
}

Bool SplayTreeDelete(SplayTree splay, Tree node)
{
  Tree leftLast;
  Compare cmp;

  AVERT(SplayTree, splay);
  AVERT(Tree, node);

  if (SplayTreeIsEmpty(splay))
    return FALSE;

  cmp = SplaySplay(splay, splay->nodeKey(node), splay->compare);
  AVER(cmp != CompareEQUAL || SplayTreeRoot(splay) == node);

  if (cmp != CompareEQUAL) {
    return FALSE;
  } else if (!TreeHasLeft(node)) {
    SplayTreeSetRoot(splay, TreeRight(node));
    TreeClearRight(node);
  } else if (!TreeHasRight(node)) {
    SplayTreeSetRoot(splay, TreeLeft(node));
    TreeClearLeft(node);
  } else {
    Tree rightHalf = TreeRight(node);
    TreeClearRight(node);
    SplayTreeSetRoot(splay, TreeLeft(node));
    TreeClearLeft(node);
    (void)SplaySplay(splay, NULL, compareGreater);
    leftLast = SplayTreeRoot(splay);
    AVER(leftLast != TreeEMPTY);
    AVER(!TreeHasRight(leftLast));
    TreeSetRight(leftLast, rightHalf);
    splay->updateNode(splay, leftLast);
  }

  TreeFinish(node);

  return TRUE;
}

static Compare SplaySplitRev(SplayStateStruct *stateReturn,
                             SplayTree splay, TreeKey key,
                             TreeCompareFunction compare)
{
  Tree middle, leftLast, rightFirst;
  Compare cmp;

  AVERT(SplayTree, splay);
  AVER(FUNCHECK(compare));
  AVER(!SplayTreeIsEmpty(splay));
  
  leftLast = TreeEMPTY;
  rightFirst = TreeEMPTY;
  middle = SplayTreeRoot(splay);
  for (;;) {
    cmp = compare(middle, key);
    switch(cmp) {
    default:
      NOTREACHED;
      /* defensive fall-through */
    case CompareEQUAL:
      goto stop;

    case CompareLESS:
      if (!TreeHasLeft(middle))
        goto stop;
      middle = SplayZigRev(middle, &rightFirst);
      cmp = compare(middle, key);
      switch(cmp) {
      default:
        NOTREACHED;
        /* defensive fall-through */
      case CompareEQUAL:
        goto stop;
      case CompareLESS:
        if (!TreeHasLeft(middle))
          goto stop;
        middle = SplayZigZigRev(middle, &rightFirst);
        splay->updateNode(splay, TreeRight(rightFirst));
        break;
      case CompareGREATER:
        if (!TreeHasRight(middle))
          goto stop;
        middle = SplayZagRev(middle, &leftLast);
        break;
      }
      break;

    case CompareGREATER:
      if (!TreeHasRight(middle))
        goto stop;
      middle = SplayZagRev(middle, &leftLast);
      cmp = compare(middle, key);
      switch(cmp) {
      default:
        NOTREACHED;
        /* defensive fall-through */
      case CompareEQUAL:
        goto stop;
      case CompareGREATER:
        if (!TreeHasRight(middle))
          goto stop;
        middle = SplayZagZagRev(middle, &leftLast);
        splay->updateNode(splay, TreeLeft(leftLast));
        break;
      case CompareLESS:
        if (!TreeHasLeft(middle))
          goto stop;
        middle = SplayZigRev(middle, &rightFirst);
        break;
      }
      break;
    }
  }

stop:
  stateReturn->middle = middle;
  stateReturn->leftLast = leftLast;
  stateReturn->rightFirst = rightFirst;
  return cmp;
}