private bool RemoveInternal(TKey key, Boolean matchValue, TValue value)
{
if (_count == 0)
{
return(false);
}
ConcurrentSkipListMapNode <TKey, TValue> traverseNode = _head;
var backlook = GenerateInitialBacklook();
var nextIndex = TraverseNextStep(traverseNode.Forwards, key);
Boolean found = false;
while (nextIndex != null)
{
for (var i = nextIndex.Value; i < traverseNode.Forwards.Length; i++)
{
backlook[i] = traverseNode;
}
traverseNode = traverseNode.Forwards[nextIndex.Value];
if (_comparer.Compare(traverseNode.Key, key) == 0)
{
if (matchValue && EqualityComparer <TValue> .Default.Equals(traverseNode.Value, value) == false)
{
return(false);
}
found = true;
break;
}
else if (_comparer.Compare(key, traverseNode.Key) < 0)
{
return(false);
}
nextIndex = TraverseNextStep(traverseNode.Forwards, key);
}
if (found == false)
{
return(false);
}
var foundNode = traverseNode;
var prevNode = backlook[nextIndex.Value];
for (var i = 0; i < nextIndex.Value; i++)
{
backlook[i] = prevNode;
}
for (var i = 0; i < foundNode.Forwards.Length; i++)
{
backlook[i].Forwards[i] = foundNode.Forwards[i];
}
_count--;
return(true);
}
private ConcurrentSkipListMapNode <TKey, TValue>[] GenerateInitialBacklook()
{
var backlook = new ConcurrentSkipListMapNode <TKey, TValue> [_head.Forwards.Length];
for (var i = 0; i < backlook.Length; i++)
{
backlook[i] = _head;
}
return(backlook);
}
public bool MoveNext()
{
if (_currentNode.Forwards[0] != null)
{
_currentNode = _currentNode.Forwards[0];
_current = new KeyValuePair <TKey, TValue>(_currentNode.Key, _currentNode.Value);
return(true);
}
_currentNode = default;
_current = new KeyValuePair <TKey, TValue>();
return(false);
}
public void Add(TKey key, TValue value)
{
if (key == null)
{
throw new ArgumentNullException(nameof(key));
}
ConcurrentSkipListMapNode <TKey, TValue> traverseNode = _head;
var backlook = new ConcurrentSkipListMapNode <TKey, TValue> [_head.Forwards.Length];
var nextIndex = TraverseNextStep(_head.Forwards, key);
while (nextIndex != null)
{
for (var i = nextIndex.Value; i < traverseNode.Forwards.Length; i++)
{
backlook[i] = traverseNode;
}
traverseNode = traverseNode.Forwards[nextIndex.Value];
if (_comparer.Compare(traverseNode.Key, key) == 0)
{
throw new ArgumentException("the key already exists", nameof(key));
}
nextIndex = TraverseNextStep(traverseNode.Forwards, key);
}
for (var i = 0; i < traverseNode.Forwards.Length; i++)
{
backlook[i] = traverseNode;
}
var forwardLength = NewForwardLength();
var newNode = new ConcurrentSkipListMapNode <TKey, TValue>(forwardLength)
{
Key = key, Value = value
};
for (var i = 0; i < forwardLength; i++)
{
var prevNode = backlook[i];
var nextNode = prevNode?.Forwards[i];
newNode.Forwards[i] = nextNode;
prevNode.Forwards[i] = newNode;
}
_count++;
}
public Boolean TryGetValue(TKey key, out TValue value)
{
ConcurrentSkipListMapNode <TKey, TValue> traverseNode = _head;
var nextIndex = TraverseNextStep(traverseNode.Forwards, key);
while (nextIndex != null)
{
traverseNode = traverseNode.Forwards[nextIndex.Value];
if (_comparer.Compare(traverseNode.Key, key) == 0)
{
value = traverseNode.Value;
return(true);
}
nextIndex = TraverseNextStep(traverseNode.Forwards, key);
}
value = default;
return(false);
}
public void Reset()
{
_currentNode = _skipListMap._head;
_current = new KeyValuePair <TKey, TValue>();
}
internal Enumerator(ConcurrentSkipListMap <TKey, TValue> skipListMap)
{
_skipListMap = skipListMap;
_currentNode = _skipListMap._head;
_current = new KeyValuePair <TKey, TValue>();
}