Avalonia/Perspex.Base/Threading/NGenerics/RedBlackTreeDictionary.cs

/*  
  Copyright 2007-2013 The NGenerics Team
 (https://github.com/ngenerics/ngenerics/wiki/Team)

 This program is licensed under the GNU Lesser General Public License (LGPL).  You should 
 have received a copy of the license along with the source code.  If not, an online copy
 of the license can be found at http://www.gnu.org/copyleft/lesser.html.
*/


/*
 * The insertion and deletion code is based on the code found at http://eternallyconfuzzled.com/tuts/redblack.htm.
 * It's an excellent tutorial - if you want to understand Red Black trees, look there first.
 */

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Diagnostics.CodeAnalysis;
using NGenerics.Comparers;
using NGenerics.Patterns.Visitor;

namespace NGenerics.DataStructures.Trees
{
	/// <summary>
	/// An implementation of a Red-Black tree.
	/// </summary>
	/// <typeparam name="TKey">The type of the keys in the <see cref="RedBlackTree{TKey,TValue}"/>.</typeparam>
	/// <typeparam name="TValue">The type of the values in the <see cref="RedBlackTree{TKey,TValue}"/>.</typeparam>
	[SuppressMessage("Microsoft.Naming", "CA1710:IdentifiersShouldHaveCorrectSuffix")]
#if (!SILVERLIGHT && !WINDOWSPHONE)
    //[Serializable]
#endif
    internal class RedBlackTree<TKey, TValue> : RedBlackTree<KeyValuePair<TKey, TValue>>, IDictionary<TKey, TValue>  // BinarySearchTreeBase<TKey, TValue>
	{
		#region Construction
		/// <inheritdoc />
		public RedBlackTree() : base(new KeyValuePairComparer<TKey, TValue>())
		{
			// Do nothing - the default Comparer will be used by the base class.
		}


		/// <inheritdoc/>
		public RedBlackTree(IComparer<TKey> comparer)
			: base(new KeyValuePairComparer<TKey, TValue>(comparer))
		{
			// Do nothing else.
		}

		/// <inheritdoc/>
		public RedBlackTree(Comparison<TKey> comparison)
			: base(new KeyValuePairComparer<TKey, TValue>(comparison))
		{
			// Do nothing else.
		}

		#endregion
		
		#region Private Members

		private RedBlackTreeNode<KeyValuePair<TKey, TValue>> FindNode(TKey key)
		{
			return base.FindNode(new KeyValuePair<TKey, TValue>(key, default(TValue))) as RedBlackTreeNode<KeyValuePair<TKey, TValue>>;
		}

		private bool Contains(KeyValuePair<TKey, TValue> item, bool checkValue) {
			var node = FindNode(item);

			if ((node != null) && !checkValue) {
				return true;
			}

			return node != null && Equals(item.Value, node.Data.Value);
		}

		#endregion

		#region IDictionary<TKey,TValue> Members

		/// <summary>
		/// Removes the element with the specified key from the <see cref="T:System.Collections.Generic.IDictionary`2"/>.
		/// </summary>
		/// <param name="key">The key of the element to remove.</param>
		/// <returns>
		/// true if the element is successfully removed; otherwise, false.  This method also returns false if <paramref name="key"/> was not found in the original <see cref="T:System.Collections.Generic.IDictionary`2"/>.
		/// </returns>
		/// <exception cref="T:System.ArgumentNullException">
		/// 	<paramref name="key"/> is null.
		/// </exception>
		/// <exception cref="T:System.NotSupportedException">
		/// The <see cref="T:System.Collections.Generic.IDictionary`2"/> is read-only.
		/// </exception>
		public bool Remove(TKey key) {
			return Remove(new KeyValuePair<TKey, TValue>(key, default(TValue)));
		}

		/// <summary>
		/// Adds an element with the provided key and value to the <see cref="T:System.Collections.Generic.IDictionary`2"/>.
		/// </summary>
		/// <param name="key">The object to use as the key of the element to add.</param>
		/// <param name="value">The object to use as the value of the element to add.</param>
		/// <exception cref="T:System.ArgumentNullException">
		/// 	<paramref name="key"/> is null.
		/// </exception>
		/// <exception cref="T:System.ArgumentException">
		/// An element with the same key already exists in the <see cref="T:System.Collections.Generic.IDictionary`2"/>.
		/// </exception>
		/// <exception cref="T:System.NotSupportedException">
		/// The <see cref="T:System.Collections.Generic.IDictionary`2"/> is read-only.
		/// </exception>
		public void Add(TKey key, TValue value) {

			if (Equals(key, null))
			{
				throw new ArgumentNullException("key");
			}

			Add(new KeyValuePair<TKey,TValue>(key, value));
		}

		/// <summary>
		/// Determines whether the <see cref="T:System.Collections.Generic.IDictionary`2"/> contains an element with the specified key.
		/// </summary>
		/// <param name="key">The key to locate in the <see cref="T:System.Collections.Generic.IDictionary`2"/>.</param>
		/// <returns>
		/// true if the <see cref="T:System.Collections.Generic.IDictionary`2"/> contains an element with the key; otherwise, false.
		/// </returns>
		/// <exception cref="T:System.ArgumentNullException">
		/// 	<paramref name="key"/> is null.
		/// </exception>
		public bool ContainsKey(TKey key) {
			return Contains(new KeyValuePair<TKey, TValue>(key, default(TValue)), false);
		}

		/// <summary>
		/// Gets an <see cref="T:System.Collections.Generic.ICollection`1"/> containing the keys of the <see cref="T:System.Collections.Generic.IDictionary`2"/>.
		/// </summary>
		/// <value></value>
		/// <example>
		/// 	<code source="..\..\Source\Examples\ExampleLibraryCSharp\DataStructures\Trees\BinarySearchTreeBaseExamples.cs" region="Keys" lang="cs" title="The following example shows how to use the Keys property."/>
		/// 	<code source="..\..\Source\Examples\ExampleLibraryVB\DataStructures\Trees\BinarySearchTreeBaseExamples.vb" region="Keys" lang="vbnet" title="The following example shows how to use the Keys property."/>
		/// </example>
		public ICollection<TKey> Keys
		{
			get
			{
				// Get the keys in sorted order
				var visitor = new KeyTrackingVisitor<TKey, TValue>();
				var inOrderVisitor = new InOrderVisitor<KeyValuePair<TKey, TValue>>(visitor);
				DepthFirstTraversal(inOrderVisitor);
				return new ReadOnlyCollection<TKey>(visitor.TrackingList);
			}
		}

		
		/// <inheritdoc />
		/// <example>
		/// <code source="..\..\Source\Examples\ExampleLibraryCSharp\DataStructures\Trees\BinarySearchTreeBaseExamples.cs" region="TryGetValue" lang="cs" title="The following example shows how to use the TryGetValue method."/>
		/// <code source="..\..\Source\Examples\ExampleLibraryVB\DataStructures\Trees\BinarySearchTreeBaseExamples.vb" region="TryGetValue" lang="vbnet" title="The following example shows how to use the TryGetValue method."/>
		/// </example>
		public bool TryGetValue(TKey key, out TValue value)
		{
			var node = FindNode(new KeyValuePair<TKey, TValue>(key, default(TValue)));

			if (node == null)
			{
				value = default(TValue);
				return false;
			}
			
			value = node.Data.Value;
			return true;
		}

		/// <summary>
		/// Gets an <see cref="T:System.Collections.Generic.ICollection`1"/> containing the values in the <see cref="T:System.Collections.Generic.IDictionary`2"/>.
		/// </summary>
		/// <value></value>
		/// <example>
		/// 	<code source="..\..\Source\Examples\ExampleLibraryCSharp\DataStructures\Trees\BinarySearchTreeBaseExamples.cs" region="Values" lang="cs" title="The following example shows how to use the Values property."/>
		/// 	<code source="..\..\Source\Examples\ExampleLibraryVB\DataStructures\Trees\BinarySearchTreeBaseExamples.vb" region="Values" lang="vbnet" title="The following example shows how to use the Values property."/>
		/// </example>
		public ICollection<TValue> Values
		{
			get
			{
				var visitor = new ValueTrackingVisitor<TKey, TValue>();
				var inOrderVisitor = new InOrderVisitor<KeyValuePair<TKey, TValue>>(visitor);

				DepthFirstTraversal(inOrderVisitor);

				return new ReadOnlyCollection<TValue>(visitor.TrackingList);
			}
		}


		/// <summary>
		/// Gets or sets the value with the specified key.
		/// </summary>
		/// <value>The key of the item to set or get.</value>
		public TValue this[TKey key]
		{
			get
			{
				var node = FindNode(key);

				if (node == null)
				{
					throw new KeyNotFoundException("key");
				}

				return node.Data.Value;
			}
			set
			{
				var node = FindNode(key);

				if (node == null)
				{
					throw new KeyNotFoundException("key");
				}

				node.Data = new KeyValuePair<TKey,TValue>(key, value);
			}
		}

		#endregion

		#region ICollection<KeyValuePair<TKey,TValue>> Members
		
		/// <inheritdoc />
		/// <example>
		/// <code source="..\..\Source\Examples\ExampleLibraryCSharp\DataStructures\Trees\BinarySearchTreeBaseExamples.cs" region="Contains" lang="cs" title="The following example shows how to use the Contains method."/>
		/// <code source="..\..\Source\Examples\ExampleLibraryVB\DataStructures\Trees\BinarySearchTreeBaseExamples.vb" region="Contains" lang="vbnet" title="The following example shows how to use the Contains method."/>
		/// </example>
		public override bool Contains(KeyValuePair<TKey, TValue> item) {
			return Contains(item, true);
		}

		#endregion
	}
}