private static ImmutableHashTree <TKey, TValue> RotateRight(ImmutableHashTree <TKey, TValue> node)
{
return(new ImmutableHashTree <TKey, TValue>(
node.Left.Key,
node.Left.Value,
node.Left.Left,
new ImmutableHashTree <TKey, TValue>(node.Key, node.Value, node.Left.Right, node.Right)));
}
/// <summary>
/// Initializes a new instance of the <see cref="ImmutableHashTree{TKey,TValue}"/> class
/// and adds a new entry in the <see cref="Duplicates"/> list.
/// </summary>
/// <param name="key">The key for this node.</param>
/// <param name="value">The value for this node.</param>
/// <param name="hashTree">The <see cref="ImmutableHashTree{TKey,TValue}"/> that contains existing duplicates.</param>
public ImmutableHashTree(TKey key, TValue value, ImmutableHashTree <TKey, TValue> hashTree)
{
Duplicates = hashTree.Duplicates.Add(new KeyValue <TKey, TValue>(key, value));
Key = hashTree.Key;
Value = hashTree.Value;
Height = hashTree.Height;
HashCode = hashTree.HashCode;
Left = hashTree.Left;
Right = hashTree.Right;
}
/// <summary>
/// Initializes a new instance of the <see cref="ImmutableHashTree{TKey,TValue}"/> class.
/// </summary>
/// <param name="key">The key for this node.</param>
/// <param name="value">The value for this node.</param>
/// <param name="left">The left node.</param>
/// <param name="right">The right node.</param>
public ImmutableHashTree(TKey key, TValue value, ImmutableHashTree <TKey, TValue> left, ImmutableHashTree <TKey, TValue> right)
{
var balance = left.Height - right.Height;
if (balance == -2)
{
if (right.IsLeftHeavy())
{
right = RotateRight(right);
}
// Rotate left
Key = right.Key;
Value = right.Value;
Left = new ImmutableHashTree <TKey, TValue>(key, value, left, right.Left);
Right = right.Right;
}
else if (balance == 2)
{
if (left.IsRightHeavy())
{
left = RotateLeft(left);
}
// Rotate right
Key = left.Key;
Value = left.Value;
Right = new ImmutableHashTree <TKey, TValue>(key, value, left.Right, right);
Left = left.Left;
}
else
{
Key = key;
Value = value;
Left = left;
Right = right;
}
Height = 1 + Math.Max(Left.Height, Right.Height);
Duplicates = ImmutableList <KeyValue <TKey, TValue> > .Empty;
HashCode = Key.GetHashCode();
}
