C++ VNode::isRoot方法代码示例

//remove an existed Entry(_entity_id) from VSTree 
bool 
VSTree::removeEntry(int _entity_id)
{
    VNode* leafNodePtr = this->getLeafNodeByEntityID(_entity_id);

    if (leafNodePtr == NULL)
    {
        cerr<< "error, can not find the mapping leaf node. @VSTree::removeEntry" << endl;
        return false;
    }

    // seek the entry index of the leaf node.
    int entryIndex = -1;
    int childNum = leafNodePtr->getChildNum();

	//cout<<"root file line: "<<this->root_file_line<<"   "<<"max nid num: "<<this->max_nid_alloc<<endl;
	//cout<<"node num: "<<this->node_num<<"   "<<"file line: "<<leafNodePtr->getFileLine()<<"   "<<"child num: "<<childNum<<endl;

    for(int i = 0; i < childNum; i++)
    {
        if(leafNodePtr->getChildEntry(i).getEntityId() == _entity_id)
        {
            entryIndex = i;
            break;
        }
    }

    if(entryIndex == -1)
    {
        cerr << "error, can not find the entry in leaf node. @VSTree::removeEntry" << endl;
        return false;
    }

	//BETTER?:consider up->bopttom to deal, not find leaf and recursively
	if(leafNodePtr->isRoot())
	{
		if(childNum == 1)
		{   //the tree is empty now
			leafNodePtr->removeChild(entryIndex);
			leafNodePtr->refreshAncestorSignature(*(this->node_buffer));
			this->removeNode(leafNodePtr);
			this->root_file_line = -1;
			this->height = 0;
			this->entry_num = 0;
			this->node_num = 0;
		}
		else
		{
			leafNodePtr->removeChild(entryIndex);
			leafNodePtr->refreshAncestorSignature(*(this->node_buffer));
		}
	}
	else
	{
		if(childNum <= VNode::MIN_CHILD_NUM)
		{
			//cerr << "In VSTree::remove() -- the node is invalid" << endl;
			//TODO+BETTER:this may search again, too costly
			//VNode* fatherNodePtr = leafNodePtr->getFather(*(this->node_buffer));
			////int index = leafNodePtr->getIndexInFatherNode(*(this->node_buffer));
			//int n = fatherNodePtr->getChildNum();
			//for (int i = 0; i < n; ++i)
			//{
				//if (fatherNodePtr->getChildFileLine(i) == leafNodePtr->getFileLine())
				//{
					//this->coalesce(fatherNodePtr, i, leafNodePtr, entryIndex);
					//break;
				//}
			//}
			//return false;
			this->coalesce(leafNodePtr, entryIndex);
		}
		else
		{
			leafNodePtr->removeChild(entryIndex);
			leafNodePtr->refreshAncestorSignature(*(this->node_buffer));
		}
	}


	this->entry_num--;
	this->entityID2FileLineMap.erase(_entity_id);

     //NOTICE:insert is costly but can keep balance.
	 //However, remove is not too costly but can not keep balance at all.
	 //And remove maybe error if without coalesce!
	 //If remove and insert are both wonderful, update/replace can both be balanced using delete and insert again.
	 //(not care the balance now, if insert/delete many times, rebuilding is suggested)

	 //we do not consider the situation which the leaf node is to be empty by now...
	 //in a better way, if the leaf node is empty after removing entry, we should delete it. and recursively judge whether its
	 //father is empty, and delete its father node if true. to make the VSTree more balanced, we should combine two nodes if
	 //their child number are less than the MIN_CHILD_NUM. when deleting one node from the tree, we should also remove it from
	 //tree node file in hard disk by doing some operations on the node_buffer.

    return true;
}

//.........这里部分代码省略.........
    sort(entryIndex_nearA.begin(), entryIndex_nearA.end(), less<int>());

#ifdef DEBUG_VSTREE
    	stringstream _ss1;
    	{
    		_ss1 << "nearA: ";
    		for(unsigned i = 0; i < entryIndex_nearA.size(); i++)
    		{
    			_ss1 << entryIndex_nearA[i] << " ";
    		}
    		_ss1 << endl;

    		_ss1 << "nearB: ";
    		for(unsigned i = 0; i < entryIndex_nearB.size(); i++)
    		{
    			_ss1 << entryIndex_nearB[i] << " ";
    		}
    		_ss1 << endl;
    	}
    	Util::logging(_ss1.str());
#endif

    for(unsigned i = 0; i < entryIndex_nearA.size(); i++)
    {
        oldNodePtr->setChildEntry(i, oldNodePtr->getChildEntry(entryIndex_nearA[i]));
        oldNodePtr->setChildFileLine(i, oldNodePtr->getChildFileLine(entryIndex_nearA[i]));
    }
    oldNodePtr->setChildNum(entryIndex_nearA.size());
    oldNodePtr->refreshSignature();

    int oldNode_index = oldNodePtr->getIndexInFatherNode(*(this->node_buffer));
    // full node's father pointer.
    VNode* oldNodeFatherPtr = oldNodePtr->getFather(*(this->node_buffer));
    if(oldNodePtr->isRoot())
    {
         //if the old node is root,
		 //split the root, create a new root,
         //and the tree height will be increased.
        VNode* RootNewPtr = this->createNode();

         //change the old root node to not-root node,
         //and set the RootNew to root node.
        oldNodePtr->setAsRoot(false);
        RootNewPtr->setAsRoot(true);

         //set the split two node(old node and new node) as the new root's child,
         //and update signatures.
        RootNewPtr->addChildNode(oldNodePtr);
        RootNewPtr->addChildNode(newNodePtr);
        RootNewPtr->refreshSignature();

        //debug
//        {
//            stringstream _ss;
//            _ss << "create new root:" << endl;
//            _ss << "before swap file line, two sons are: " << oldNodePtr->getFileLine() << " " << newNodePtr->getFileLine() << endl;
//            Util::logging(_ss.str());
//        }

         //should keep the root node always being
         //at the first line(line zero) of the tree node file.
        this->swapNodeFileLine(RootNewPtr, oldNodePtr);
        this->height++;

        //debug
//        {

//.........这里部分代码省略.........

    //debug
//    {
//    	stringstream _ss;
//    	{
//    		_ss << "nearA: ";
//    		for(int i = 0; i < entryIndex_nearA.size(); i ++)
//    		{
//    			_ss << entryIndex_nearA[i] << " ";
//    		}
//    		_ss << endl;
//
//    		_ss << "nearB: ";
//    		for(int i = 0; i < entryIndex_nearB.size(); i ++)
//    		{
//    			_ss << entryIndex_nearB[i] << " ";
//    		}
//    		_ss << endl;
//    	}
//    	Util::logging(_ss.str());
//    }

    for (unsigned i=0;i<entryIndex_nearA.size();i++)
    {
        oldNodePtr->setChildEntry(i, oldNodePtr->getChildEntry(entryIndex_nearA[i]));
        oldNodePtr->setChildFileLine(i, oldNodePtr->getChildFileLine(entryIndex_nearA[i]));
    }
    oldNodePtr->setChildNum(entryIndex_nearA.size());
    oldNodePtr->refreshSignature();

    int oldNode_index = oldNodePtr->getIndexInFatherNode(*(this->node_buffer));
    // full node's father pointer.
    VNode* oldNodeFatherPtr = oldNodePtr->getFather(*(this->node_buffer));
    if (oldNodePtr->isRoot())
    {
        /* if the old node is root,
         * split the root, create a new root,
         * and the tree height will be increased.*/
        VNode* RootNewPtr = this->createNode();

        /* change the old root node to not-root node,
         * and set the RootNew to root node.*/
        oldNodePtr->setAsRoot(false);
        RootNewPtr->setAsRoot(true);

        /* set the split two node(old node and new node) as the new root's child,
         * and update signatures.*/
        RootNewPtr->addChildNode(oldNodePtr);
        RootNewPtr->addChildNode(newNodePtr);
        RootNewPtr->refreshSignature();

        //debug
//        {
//            stringstream _ss;
//            _ss << "create new root:" << endl;
//            _ss << "before swap file line, two sons are: " << oldNodePtr->getFileLine() << " " << newNodePtr->getFileLine() << endl;
//            Util::logging(_ss.str());
//        }

        /* should keep the root node always being
         * at the first line(line zero) of the tree node file.*/
        this->swapNodeFileLine(RootNewPtr, oldNodePtr);
        this->height ++;

        //debug
//        {