private static int IndexOfNull <TValue>(
byte[] buffer,
int index,
int count,
ref BsonTrieNode <TValue> bsonTrieNode)
{
for (; count > 0; index++, count--)
{
// bsonTrieNode might be null on entry or it might become null while navigating the trie
if (bsonTrieNode == null)
{
return(Array.IndexOf <byte>(buffer, 0, index, count));
}
var keyByte = buffer[index];
if (keyByte == 0)
{
return(index);
}
bsonTrieNode = bsonTrieNode.GetChild(keyByte); // might return null
}
return(-1);
}
/// <summary>
/// Gets the node associated with the specified element name.
/// </summary>
/// <param name="utf8">The element name.</param>
/// <param name="node">
/// When this method returns, contains the node associated with the specified element name, if the key is found;
/// otherwise, null. This parameter is passed unitialized.
/// </param>
/// <returns>True if the node was found; otherwise, false.</returns>
public bool TryGetNode(ArraySegment <byte> utf8, out BsonTrieNode <TValue> node)
{
node = _root;
for (var i = 0; node != null && i < utf8.Count; i++)
{
var keyByte = utf8.Array[utf8.Offset + i];
node = node.GetChild(keyByte);
}
return(node != null);
}
/// <summary>
/// Tries to get the node associated with a name read from a stream.
/// </summary>
/// <param name="stream">The stream.</param>
/// <param name="node">The node.</param>
/// <returns>
/// True if the node was found.
/// If the node was found the stream is advanced over the name, otherwise
/// the stream is repositioned to the beginning of the name.
/// </returns>
public bool TryGetNode(BsonStream stream, out BsonTrieNode <TValue> node)
{
var position = stream.Position;
var utf8 = stream.ReadCStringBytes();
if (TryGetNode(utf8, out node))
{
return(true);
}
stream.Position = position;
return(false);
}
// public methods
/// <summary>
/// Adds the specified elementName (after encoding as a UTF8 byte sequence) and value to the trie.
/// </summary>
/// <param name="elementName">The element name to add.</param>
/// <param name="value">The value to add. The value can be null for reference types.</param>
public void Add(string elementName, TValue value)
{
var keyBytes = __utf8Encoding.GetBytes(elementName);
var node = _root;
foreach (var keyByte in keyBytes)
{
var child = node.GetChild(keyByte);
if (child == null)
{
child = new BsonTrieNode<TValue>(keyByte);
node.AddChild(child);
}
node = child;
}
node.SetValue(elementName, value);
}
// public methods
/// <summary>
/// Adds the specified elementName (after encoding as a UTF8 byte sequence) and value to the trie.
/// </summary>
/// <param name="elementName">The element name to add.</param>
/// <param name="value">The value to add. The value can be null for reference types.</param>
public void Add(string elementName, TValue value)
{
using var rentedSegment = Utf8Encodings.Strict.GetBytesUsingThreadStaticBuffer(elementName);
var node = _root;
foreach (var keyByte in rentedSegment.Segment)
{
var child = node.GetChild(keyByte);
if (child == null)
{
child = new BsonTrieNode <TValue>(keyByte);
node.AddChild(child);
}
node = child;
}
node.SetValue(elementName, value);
}
// constructors
/// <summary>
/// Initializes a new instance of the BsonTrie class.
/// </summary>
public BsonTrie()
{
_root = new BsonTrieNode <TValue>(0);
}
// internal methods
internal void AddChild(BsonTrieNode <TValue> child)
{
if (GetChild(child._keyByte) != null)
{
throw new ArgumentException("BsonTrieNode already contains a child with the same keyByte.");
}
if (_children != null)
{
// add a new child to the existing _children
var children = new BsonTrieNode <TValue> [_children.Length + 1];
Array.Copy(_children, children, _children.Length);
children[children.Length - 1] = child;
var childrenIndexes = _childrenIndexes;
var minChildKeyByte = _minChildKeyByte;
var maxChildKeyByte = _minChildKeyByte + _childrenIndexes.Length - 1;
// if new keyByte doesn't fall within existing min/max range expand the range
if (child._keyByte < minChildKeyByte)
{
// grow the indexes on the min side
minChildKeyByte = child._keyByte;
childrenIndexes = new byte[maxChildKeyByte - minChildKeyByte + 1];
var sizeDelta = childrenIndexes.Length - _childrenIndexes.Length;
for (var i = 0; i < sizeDelta; i++)
{
childrenIndexes[i] = 255;
}
Array.Copy(_childrenIndexes, 0, childrenIndexes, sizeDelta, _childrenIndexes.Length);
}
else if (child._keyByte > maxChildKeyByte)
{
// grow the indexes on the max side
maxChildKeyByte = child._keyByte;
childrenIndexes = new byte[maxChildKeyByte - minChildKeyByte + 1];
Array.Copy(_childrenIndexes, 0, childrenIndexes, 0, _childrenIndexes.Length);
for (var i = _childrenIndexes.Length; i < childrenIndexes.Length; i++)
{
childrenIndexes[i] = 255;
}
}
childrenIndexes[child._keyByte - minChildKeyByte] = (byte)(children.Length - 1);
_children = children;
_childrenIndexes = childrenIndexes;
_minChildKeyByte = minChildKeyByte;
}
else if (_onlyChild != null)
{
// switch from having an _onlyChild to having two _children
var children = new BsonTrieNode <TValue> [2];
children[0] = _onlyChild;
children[1] = child;
var minChildKeyByte = _onlyChild._keyByte;
var maxChildKeyByte = child._keyByte;
if (minChildKeyByte > maxChildKeyByte)
{
minChildKeyByte = child._keyByte;
maxChildKeyByte = _onlyChild._keyByte;
}
var childrenIndexes = new byte[maxChildKeyByte - minChildKeyByte + 1];
for (var i = 0; i < childrenIndexes.Length; i++)
{
childrenIndexes[i] = 255;
}
childrenIndexes[_onlyChild._keyByte - minChildKeyByte] = 0;
childrenIndexes[child._keyByte - minChildKeyByte] = 1;
_onlyChild = null;
_children = children;
_childrenIndexes = childrenIndexes;
_minChildKeyByte = minChildKeyByte;
}
else
{
_onlyChild = child;
}
}
