C++ BTreeNode::Initialize方法代码示例

// The main function that inserts a new key in this B-Tree
void BTree::insert(int k)
{
	char varnam[64];

	// If tree is empty
	if (root == NULL)
	{
		bzero(varnam, 64);
		sprintf(varnam,"%d",count);
		strcat(varnam,"node");
		varnam[64]=0;
		// Allocate memory for root
		root =(BTreeNode *)nvalloc_(sizeof(BTreeNode), varnam, 0);
		//root = (BTreeNode *)nvalloc_(sizeof(BTreeNode));
		root->Initialize(root, t, true, count);	
		//root = new BTreeNode(t, true);
		root->keys[0] = k; // Insert key
		root->n = 1; // Update number of keys in root
	}
	else // If tree is not empty
	{
		// If root is full, then tree grows in height
		if (root->n == 2*t-1)
		{
			bzero(varnam, 64);
			sprintf(varnam,"%d",count);
			strcat(varnam,"node");
			varnam[64]=0;

			// Allocate memory for root
			BTreeNode *s =(BTreeNode *)nvalloc_(sizeof(BTreeNode), varnam, 0);
			s->Initialize(s, t, false, count);	
			// Allocate memory for new root
			//BTreeNode *s = new BTreeNode(t, false);
			BEGIN_OBJTRANS((void *)s,0);

			// Make old root as child of new root
			s->C[0] = root;

			// Split the old root and move 1 key to the new root
			s->splitChild(0, root);

			// New root has two children now. Decide which of the
			// two children is going to have new key
			int i = 0;
			if (s->keys[0] < k)
				i++;
			s->C[i]->insertNonFull(k);

			nvcommitobj((void *)s,0);

			// Change root
			root = s;
		}
		else // If root is not full, call insertNonFull for root
			root->insertNonFull(k);
	}
	count++;
}

// A utility function to split the child y of this node
// Note that y must be full when this function is called
void BTreeNode::splitChild(int i, BTreeNode *y)
{
	// Create a new node which is going to store (t-1) keys
	// of y
	//BTreeNode *z = new BTreeNode(y->t, y->leaf);
	char varnam[64];
	bzero(varnam, 64);
	sprintf(varnam,"%d",count);
	strcat(varnam,"node");
	varnam[64]=0;
	// Allocate memory for root
	BTreeNode *z  =(BTreeNode *)nvalloc_(sizeof(BTreeNode), varnam, 0);
	//root = (BTreeNode *)nvalloc_(sizeof(BTreeNode));
	z->Initialize(z, y->t, y->leaf, count);	

	BEGIN_OBJTRANS((void *)z,0);
	z->n = t - 1;
	// Copy the last (t-1) keys of y to z
	for (int 	j = 0; j < t-1; j++) {
		BEGIN_WRDTRANS((void *)&z->keys[j],0, sizeof(int));
		z->keys[j] = y->keys[j+t];
		nvcommitword_((void *)&z->keys[j]);
	}

	// Copy the last t children of y to z
	if (y->leaf == false)
	{
		for (int j = 0; j < t; j++) {
			BEGIN_WRDTRANS((void *)&z->C[j],0, sizeof(BTreeNode *));
			z->C[j] = y->C[j+t];
			nvcommitword_((void *)&z->C[j]);
		}
	}

	nvcommitobj((void *)z,0);

	BEGIN_WRDTRANS((void *)&y->n,0, sizeof(int));
	// Reduce the number of keys in y
	y->n = t - 1;
	nvcommitword_((void *)&y->n);

	// Since this node is going to have a new child,
	// create space of new child
	for (int j = n; j >= i+1; j--) {
		BEGIN_WRDTRANS((void *)&C[j+1],0, sizeof(BTreeNode *));
		C[j+1] = C[j];
		nvcommitword_((void *)&C[j+1]);
	}

	// Link the new child to this node
	BEGIN_WRDTRANS((void *)&C[i+1],0, sizeof(BTreeNode *));
	C[i+1] = z;
	nvcommitword_((void *)&C[i+1]);

	// A key of y will move to this node. Find location of
	// new key and move all greater keys one space ahead
	for (int j = n-1; j >= i; j--){

		BEGIN_WRDTRANS((void *)&keys[j+1],0, sizeof(int));
		keys[j+1] = keys[j];
		nvcommitword_((void *)&keys[j+1]);
	}

	BEGIN_WRDTRANS((void *)&keys[i],0, sizeof(int));
	// Copy the middle key of y to this node
	keys[i] = y->keys[t-1];
	nvcommitword_((void *)&keys[i]);

	// Increment count of keys in this node
	n = n + 1;
}