public bool Exists(byte[] key)
{
BTreeNode <T> node = FindClosestNode(key);
BTreeNodeValue <T> value = node.GetValue(key);
return(value != null);
}
public T Remove(byte[] key)
{
BTreeNode <T> node = FindClosestNode(key);
BTreeNodeValue <T> value = node.RemoveValue(key);
if (value == null)
{
return(default(T));
}
return(value.Value);
}
public void Insert(byte[] key, T value)
{
BTreeNode <T> node = FindClosestNode(key);
BTreeNodeValue <T> v = node.GetValue(key);
if (v != null)
{
throw new BTreeException("Value already exists.");
}
node.SetValue(key, value);
}
public void Reset()
{
_currentNode = _rootNode;
_currentValue = null;
_currentValueType = ValueType.None;
}
private BTreeNodeValue <T> RemoveValue(byte[] key)
{
BTreeNode <T> currentNode = this;
while (true)
{
if (key.Length == currentNode._depth)
{
currentNode._nodeValueLock.EnterWriteLock();
try
{
BTreeNodeValue <T> oldValue = currentNode._nodeValue;
currentNode._nodeValue = null;
return(oldValue);
}
finally
{
currentNode._nodeValueLock.ExitWriteLock();
}
}
if (key.Length < currentNode._depth)
{
throw new BTreeException("Cannot remove value since the key length is less than node depth.");
}
ReaderWriterLockSlim currentNodeLock = currentNode._nodeLock;
currentNodeLock.EnterWriteLock();
try
{
if (currentNode._childNodes == null)
{
//check and remove hold value
if (currentNode._holdValue == null)
{
return(null);
}
byte[] holdKey = currentNode._holdValue.Key;
if (holdKey.Length != key.Length)
{
return(null);
}
for (int i = 0; i < key.Length; i++)
{
if (holdKey[i] != key[i])
{
return(null);
}
}
BTreeNodeValue <T> oldValue = currentNode._holdValue;
currentNode._holdValue = null;
return(oldValue);
}
//set child node as current node
{
byte k = key[currentNode._depth];
BTreeNode <T> childNode = currentNode._childNodes[k];
if (childNode == null)
{
//no value set in child node
return(null);
}
currentNode = childNode;
}
}
finally
{
currentNodeLock.ExitWriteLock();
}
}
}
private BTreeNodeValue <T> SetValue(byte[] key, T value)
{
BTreeNode <T> currentNode = this;
while (true)
{
if (key.Length == currentNode._depth)
{
currentNode._nodeValueLock.EnterWriteLock();
try
{
BTreeNodeValue <T> oldValue = currentNode._nodeValue;
currentNode._nodeValue = new BTreeNodeValue <T>(key, value);
return(oldValue);
}
finally
{
currentNode._nodeValueLock.ExitWriteLock();
}
}
if (key.Length < currentNode._depth)
{
throw new BTreeException("Cannot set value since the key length is less than node depth.");
}
ReaderWriterLockSlim currentNodeLock = currentNode._nodeLock;
currentNodeLock.EnterWriteLock();
try
{
if (currentNode._childNodes == null)
{
if (currentNode._holdValue == null)
{
//set value into current node hold
BTreeNodeValue <T> oldValue = currentNode._holdValue;
currentNode._holdValue = new BTreeNodeValue <T>(key, value);
return(oldValue);
}
//explode current node & move hold value to child node
{
currentNode._childNodes = new BTreeNode <T> [256];
byte k = currentNode._holdValue.Key[currentNode._depth];
BTreeNode <T> childNode = new BTreeNode <T>(currentNode, k);
currentNode._childNodes[k] = childNode;
if (currentNode._holdValue.Key.Length == childNode._depth)
{
childNode._nodeValue = currentNode._holdValue;
}
else
{
childNode._holdValue = currentNode._holdValue;
}
currentNode._holdValue = null;
}
}
//set child node as current node
{
byte k = key[currentNode._depth];
BTreeNode <T> childNode = currentNode._childNodes[k];
if (childNode == null)
{
childNode = new BTreeNode <T>(currentNode, k);
currentNode._childNodes[k] = childNode;
}
currentNode = childNode;
}
}
finally
{
currentNodeLock.ExitWriteLock();
}
}
}
