Ext.cs

#region License

/*
 * Ext.cs
 *
 * Some parts of this code are derived from Mono (http://www.mono-project.com):
 * - GetStatusDescription is derived from HttpListenerResponse.cs (System.Net)
 * - IsPredefinedScheme is derived from Uri.cs (System)
 * - MaybeUri is derived from SUri.cs (System)
 *
 * The MIT License
 *
 * Copyright (c) 2001 Garrett Rooney
 * Copyright (c) 2003 Ian MacLean
 * Copyright (c) 2003 Ben Maurer
 * Copyright (c) 2003, 2005, 2009 Novell, Inc. (http://www.novell.com)
 * Copyright (c) 2009 Stephane Delcroix
 * Copyright (c) 2010-2016 sta.blockhead
 * Copyright © 2016 Nivloc Enterprises Ltd
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

#endregion

#region Contributors

/*
 * Contributors:
 * - Liryna <liryna.stark@gmail.com>
 * - Nikola Kovacevic <nikolak@outlook.com>
 * - Chris Swiedler
 */

#endregion

using System;
using System.Linq;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Text;
#if SSHARP
using Crestron.SimplSharp;
using Crestron.SimplSharp.CrestronIO;
using Crestron.SimplSharp.CrestronIO.Compression;
using Crestron.SimplSharp.Cryptography.X509Certificates;
using TcpClient = Crestron.SimplSharp.CrestronSockets.CrestronServerSocket;
using SSMono.Net;
using CookieCollection = WebSocketSharp.Net.CookieCollection;
using SSMono.Web;
using HttpUtility = SSMono.Web.HttpUtility;
using AsyncCallback = Crestron.SimplSharp.CrestronIO.AsyncCallback;
#else
using System.IO;
using System.IO.Compression;
using System.Net;
using System.Net.Sockets;
using System.Security.Cryptography.X509Certificates;
#endif
#if NETCF
using OpenNETCF;
#endif
using WebSocketSharp.Net;
using WebSocketSharp.Net.WebSockets;
#if !CLIENT
using WebSocketSharp.Server;
#endif
using System.Globalization;

namespace WebSocketSharp
	{
	/// <summary>
	/// Provides a set of static methods for websocket-sharp.
	/// </summary>
	public static class Ext
		{
		#region Private Fields

		private static readonly byte[] _last = new byte[] {0x00};
		private static readonly int _retry = 5;
		private const string _tspecials = "()<>@,;:\\\"/[]?={} \t";

		#endregion

		#region Private Methods

		private static byte[] compress (this byte[] data)
			{
#if NETCF
			if (data.Length == 0)
#else
			if (data.LongLength == 0)
#endif
				//return new byte[] { 0x00, 0x00, 0x00, 0xff, 0xff };
				return data;

			using (var input = new MemoryStream (data))
				return input.compressToArray ();
			}

		private static MemoryStream compress (this Stream stream)
			{
			var output = new MemoryStream ();
			if (stream.Length == 0)
				return output;

			stream.Position = 0;
			using (var ds = new DeflateStream (output, CompressionMode.Compress, true))
				{
				stream.CopyTo (ds, 1024);
				ds.Close (); // BFINAL set to 1.
				output.Write (_last, 0, 1);
				output.Position = 0;

				return output;
				}
			}

		private static byte[] compressToArray (this Stream stream)
			{
			using (var output = stream.compress ())
				{
				output.Close ();
				return output.ToArray ();
				}
			}

		private static byte[] decompress (this byte[] data)
			{
#if NETCF
			if (data.Length == 0)
#else
			if (data.LongLength == 0)
#endif
				return data;

			using (var input = new MemoryStream (data))
				return input.decompressToArray ();
			}

		private static MemoryStream decompress (this Stream stream)
			{
			var output = new MemoryStream ();
			if (stream.Length == 0)
				return output;

			stream.Position = 0;
			using (var ds = new DeflateStream (stream, CompressionMode.Decompress, true))
				{
				ds.CopyTo (output, 1024);
				output.Position = 0;

				return output;
				}
			}

		private static byte[] decompressToArray (this Stream stream)
			{
			using (var output = stream.decompress ())
				{
				output.Close ();
				return output.ToArray ();
				}
			}

		private static bool isHttpMethod (this string value)
			{
			return value == "GET"
					 || value == "HEAD"
					 || value == "POST"
					 || value == "PUT"
					 || value == "DELETE"
					 || value == "CONNECT"
					 || value == "OPTIONS"
					 || value == "TRACE";
			}

		private static bool isHttpMethod10 (this string value)
			{
			return value == "GET"
					 || value == "HEAD"
					 || value == "POST";
			}

		private static void times (this ulong n, Action action)
			{
			for (ulong i = 0; i < n; i++)
				action ();
			}

		private static string toResponseStringVersion0 (this Cookie cookie)
			{
			var output = new StringBuilder (64);
			output.AppendFormat ("{0}={1}", cookie.Name, cookie.Value);

			if (cookie.Expires != DateTime.MinValue)
				{
				output.AppendFormat ("; Expires={0}",
					cookie.Expires.ToUniversalTime ().ToString ("ddd, dd'-'MMM'-'yyyy HH':'mm':'ss 'GMT'", CultureInfo.CreateSpecificCulture ("en-US")));
				}

			if (!cookie.Path.IsNullOrEmpty ())
				output.AppendFormat ("; Path={0}", cookie.Path);

			if (!cookie.Domain.IsNullOrEmpty ())
				output.AppendFormat ("; Domain={0}", cookie.Domain);

			if (cookie.Secure)
				output.Append ("; Secure");

			if (cookie.HttpOnly)
				output.Append ("; HttpOnly");

			return output.ToString ();
			}

		private static string toResponseStringVersion1 (this Cookie cookie)
			{
			var output = new StringBuilder (64);
			output.AppendFormat ("{0}={1}; Version={2}", cookie.Name, cookie.Value, cookie.Version);

			if (cookie.Expires != DateTime.MinValue)
				output.AppendFormat ("; Max-Age={0}", cookie.MaxAge ());

			if (!cookie.Path.IsNullOrEmpty ())
				output.AppendFormat ("; Path={0}", cookie.Path);

			if (!cookie.Domain.IsNullOrEmpty ())
				output.AppendFormat ("; Domain={0}", cookie.Domain);

			if (!cookie.Port.IsNullOrEmpty ())
				{
				if (cookie.Port == "\"\"")
					output.Append ("; Port");
				else
					output.AppendFormat ("; Port={0}", cookie.Port);
				}

			if (!cookie.Comment.IsNullOrEmpty ())
				output.AppendFormat ("; Comment={0}", cookie.Comment.UrlEncode ());

			if (cookie.CommentUri != null)
				{
				var url = cookie.CommentUri.OriginalString;
				output.AppendFormat ("; CommentURL={0}", url.IsToken () ? url : url.Quote ());
				}

			if (cookie.Discard)
				output.Append ("; Discard");

			if (cookie.Secure)
				output.Append ("; Secure");

			return output.ToString ();
			}

		#endregion

		#region Internal Methods

		internal static byte[] Append (this ushort code, string reason)
			{
			var ret = code.InternalToByteArray (ByteOrder.Big);
			if (reason != null && reason.Length > 0)
				{
				var buff = new List<byte> (ret);
				buff.AddRange (Encoding.UTF8.GetBytes (reason));
				ret = buff.ToArray ();
				}

			return ret;
			}

#if !CLIENT
		internal static void Close (this HttpListenerResponse response, HttpStatusCode code)
			{
			response.StatusCode = (int)code;
			response.OutputStream.Close ();
			}

		internal static void CloseWithAuthChallenge (this HttpListenerResponse response, string challenge)
			{
			response.Headers.InternalSet ("WWW-Authenticate", challenge, true);
			response.Close (HttpStatusCode.Unauthorized);
			}
#endif

		internal static byte[] Compress (this byte[] data, CompressionMethod method)
			{
			return method == CompressionMethod.Deflate ? data.compress () : data;
			}

		internal static Stream Compress (this Stream stream, CompressionMethod method)
			{
			return method == CompressionMethod.Deflate ? stream.compress () : stream;
			}

		internal static byte[] CompressToArray (this Stream stream, CompressionMethod method)
			{
			return method == CompressionMethod.Deflate ? stream.compressToArray () : stream.ToByteArray ();
			}

		/// <summary>
		/// Determines whether the specified string contains any of characters in
		/// the specified array of <see cref="char"/>.
		/// </summary>
		/// <returns>
		/// <c>true</c> if <paramref name="value"/> contains any of characters in
		/// <paramref name="anyOf"/>; otherwise, <c>false</c>.
		/// </returns>
		/// <param name="value">
		/// A <see cref="string"/> to test.
		/// </param>
		/// <param name="anyOf">
		/// An array of <see cref="char"/> that contains one or more characters to
		/// seek.
		/// </param>
		internal static bool Contains (this string value, params char[] anyOf)
			{
			return anyOf != null && anyOf.Length > 0
					 ? value.IndexOfAny (anyOf) > -1
					 : false;
			}

		internal static bool Contains (this NameValueCollection collection, string name)
			{
			return collection[name] != null;
			}

		internal static bool Contains (this NameValueCollection collection, string name, string value, StringComparison comparisonTypeForValue)
			{
			var val = collection[name];
			if (val == null)
				return false;

			foreach (var elm in val.Split (','))
				{
				if (elm.Trim ().Equals (value, comparisonTypeForValue))
					return true;
				}

			return false;
			}

		internal static bool Contains<T> (this IEnumerable<T> source, Func<T, bool> condition)
			{
			foreach (T elm in source)
				{
				if (condition (elm))
					return true;
				}

			return false;
			}

		internal static bool ContainsTwice (this string[] values)
			{
			var len = values.Length;
			var end = len - 1;

			Func<int, bool> seek = null;
			seek = idx =>
				{
				if (idx == end)
					return false;

				var val = values[idx];
				for (var i = idx + 1; i < len; i++)
					{
					if (values[i] == val)
						return true;
					}

				return seek (++idx);
				};

			return seek (0);
			}

		internal static T[] Copy<T> (this T[] source, int length)
			{
			var dest = new T[length];
			Array.Copy (source, 0, dest, 0, length);

			return dest;
			}

		internal static T[] Copy<T> (this T[] source, long length)
			{
			var dest = new T[length];
#if NETCF
			Array.Copy (source, 0, dest, 0, (int)length);
#else
			Array.Copy (source, 0, dest, 0, length);
#endif

			return dest;
			}

		internal static void CopyTo (this Stream source, Stream destination, int bufferLength)
			{
			var buff = new byte[bufferLength];
			var nread = 0;
			while ((nread = source.Read (buff, 0, bufferLength)) > 0)
				destination.Write (buff, 0, nread);
			}

		internal static void CopyToAsync (this Stream source, Stream destination, int bufferLength, Action completed, Action<Exception> error)
			{
			var buff = new byte[bufferLength];

			AsyncCallback callback = null;
			callback = ar =>
				{
				try
					{
					var nread = source.EndRead (ar);
					if (nread <= 0)
						{
						if (completed != null)
							completed ();

						return;
						}

					destination.Write (buff, 0, nread);
					source.BeginRead (buff, 0, bufferLength, callback, null);
					}
				catch (Exception ex)
					{
					if (error != null)
						error (ex);
					}
				};

			try
				{
				source.BeginRead (buff, 0, bufferLength, callback, null);
				}
			catch (Exception ex)
				{
				if (error != null)
					error (ex);
				}
			}

		internal static byte[] Decompress (this byte[] data, CompressionMethod method)
			{
			return method == CompressionMethod.Deflate ? data.decompress () : data;
			}

		internal static Stream Decompress (this Stream stream, CompressionMethod method)
			{
			return method == CompressionMethod.Deflate ? stream.decompress () : stream;
			}

		internal static byte[] DecompressToArray (this Stream stream, CompressionMethod method)
			{
			return method == CompressionMethod.Deflate ? stream.decompressToArray () : stream.ToByteArray ();
			}

		/// <summary>
		/// Determines whether the specified <see cref="int"/> equals the specified <see cref="char"/>,
		/// and invokes the specified <c>Action&lt;int&gt;</c> delegate at the same time.
		/// </summary>
		/// <returns>
		/// <c>true</c> if <paramref name="value"/> equals <paramref name="c"/>;
		/// otherwise, <c>false</c>.
		/// </returns>
		/// <param name="value">
		/// An <see cref="int"/> to compare.
		/// </param>
		/// <param name="c">
		/// A <see cref="char"/> to compare.
		/// </param>
		/// <param name="action">
		/// An <c>Action&lt;int&gt;</c> delegate that references the method(s) called
		/// at the same time as comparing. An <see cref="int"/> parameter to pass to
		/// the method(s) is <paramref name="value"/>.
		/// </param>
		internal static bool EqualsWith (this int value, char c, Action<int> action)
			{
			action (value);
			return value == c - 0;
			}

		/// <summary>
		/// Gets the absolute path from the specified <see cref="Uri"/>.
		/// </summary>
		/// <returns>
		/// A <see cref="string"/> that represents the absolute path if it's successfully found;
		/// otherwise, <see langword="null"/>.
		/// </returns>
		/// <param name="uri">
		/// A <see cref="Uri"/> that represents the URI to get the absolute path from.
		/// </param>
		internal static string GetAbsolutePath (this Uri uri)
			{
			if (uri.IsAbsoluteUri)
				return uri.AbsolutePath;

			var original = uri.OriginalString;
			if (original[0] != '/')
				return null;

			var idx = original.IndexOfAny (new[] {'?', '#'});
			return idx > 0 ? original.Substring (0, idx) : original;
			}

		internal static CookieCollection GetCookies (this NameValueCollection headers, bool response)
			{
			var val = headers[response ? "Set-Cookie" : "Cookie"];
			return val != null ? CookieCollection.Parse (val, response) : new CookieCollection ();
			}

		internal static string GetDnsSafeHost (this Uri uri, bool bracketIPv6)
			{
			return bracketIPv6 && uri.HostNameType == UriHostNameType.IPv6 ? uri.Host : uri.DnsSafeHost;
			}

		internal static string GetMessage (this CloseStatusCode code)
			{
			return code == CloseStatusCode.ProtocolError
						? "A WebSocket protocol error has occurred."
						: code == CloseStatusCode.UnsupportedData
								? "An incorrect data has been received."
								: code == CloseStatusCode.Abnormal
										? "An exception has occurred."
										: code == CloseStatusCode.InvalidData
												? "An inconsistent data has been received."
												: code == CloseStatusCode.PolicyViolation
														? "A policy violation has occurred."
														: code == CloseStatusCode.TooBig
																? "A too big data has been received."
																: code == CloseStatusCode.MandatoryExtension
																		? "WebSocket client didn't receive expected extension(s)."
																		: code == CloseStatusCode.ServerError
																				? "WebSocket server got an internal error."
																				: code == CloseStatusCode.TlsHandshakeFailure ? "An error has occurred durreng a TLS handshake." : String.Empty;
			}

		/// <summary>
		/// Gets the name from the specified string that contains a pair of
		/// name and value separated by a character.
		/// </summary>
		/// <returns>
		///   <para>
		///   A <see cref="string"/> that represents the name.
		///   </para>
		///   <para>
		///   <see langword="null"/> if the name is not present.
		///   </para>
		/// </returns>
		/// <param name="nameAndValue">
		/// A <see cref="string"/> that contains a pair of name and value.
		/// </param>
		/// <param name="separator">
		/// A <see cref="char"/> used to separate name and value.
		/// </param>
		internal static string GetName (this string nameAndValue, char separator)
			{
			var idx = nameAndValue.IndexOf (separator);
			return idx > 0 ? nameAndValue.Substring (0, idx).Trim () : null;
			}

		/// <summary>
		/// Gets the value from the specified string that contains a pair of
		/// name and value separated by a character.
		/// </summary>
		/// <returns>
		///   <para>
		///   A <see cref="string"/> that represents the value.
		///   </para>
		///   <para>
		///   <see langword="null"/> if the value is not present.
		///   </para>
		/// </returns>
		/// <param name="nameAndValue">
		/// A <see cref="string"/> that contains a pair of name and value.
		/// </param>
		/// <param name="separator">
		/// A <see cref="char"/> used to separate name and value.
		/// </param>
		internal static string GetValue (this string nameAndValue, char separator)
			{
			return nameAndValue.GetValue (separator, false);
			}

		/// <summary>
		/// Gets the value from the specified string that contains a pair of
		/// name and value separated by a character.
		/// </summary>
		/// <returns>
		///   <para>
		///   A <see cref="string"/> that represents the value.
		///   </para>
		///   <para>
		///   <see langword="null"/> if the value is not present.
		///   </para>
		/// </returns>
		/// <param name="nameAndValue">
		/// A <see cref="string"/> that contains a pair of name and value.
		/// </param>
		/// <param name="separator">
		/// A <see cref="char"/> used to separate name and value.
		/// </param>
		/// <param name="unquote">
		/// A <see cref="bool"/>: <c>true</c> if unquotes the value; otherwise,
		/// <c>false</c>.
		/// </param>
		internal static string GetValue (this string nameAndValue, char separator, bool unquote)
			{
			var idx = nameAndValue.IndexOf (separator);
			if (idx < 0 || idx == nameAndValue.Length - 1)
				return null;

			var val = nameAndValue.Substring (idx + 1).Trim ();
			return unquote ? val.Unquote () : val;
			}

		internal static byte[] InternalToByteArray (this ushort value, ByteOrder order)
			{
			var bytes = BitConverter.GetBytes (value);
			if (!order.IsHostOrder ())
				Array.Reverse (bytes);

			return bytes;
			}

		internal static byte[] InternalToByteArray (this ulong value, ByteOrder order)
			{
			var bytes = BitConverter.GetBytes (value);
			if (!order.IsHostOrder ())
				Array.Reverse (bytes);

			return bytes;
			}

		internal static bool IsCompressionExtension (this string value, CompressionMethod method)
			{
			return value.StartsWith (method.ToExtensionString ());
			}

		internal static bool IsControl (this byte opcode)
			{
			return opcode > 0x7 && opcode < 0x10;
			}

		internal static bool IsControl (this Opcode opcode)
			{
			return opcode >= Opcode.Close;
			}

		internal static bool IsData (this byte opcode)
			{
			return opcode == 0x1 || opcode == 0x2;
			}

		internal static bool IsData (this Opcode opcode)
			{
			return opcode == Opcode.Text || opcode == Opcode.Binary;
			}

		internal static bool IsHttpMethod (this string value, Version version)
			{
			return version == HttpVersion.Version10
					 ? value.isHttpMethod10 ()
					 : value.isHttpMethod ();
			}

		internal static bool IsPortNumber (this int value)
			{
			return value > 0 && value < 65536;
			}

		internal static bool IsReserved (this ushort code)
			{
			return code == 1004 || code == 1005 || code == 1006 || code == 1015;
			}

		internal static bool IsReserved (this CloseStatusCode code)
			{
			return code == CloseStatusCode.Undefined || code == CloseStatusCode.NoStatus || code == CloseStatusCode.Abnormal
					|| code == CloseStatusCode.TlsHandshakeFailure;
			}

		internal static bool IsSupported (this byte opcode)
			{
			return Enum.IsDefined (typeof(Opcode), opcode);
			}

		internal static bool IsText (this string value)
			{
			var len = value.Length;
			for (var i = 0; i < len; i++)
				{
				var c = value[i];
				if (c < 0x20)
					{
					if ("\r\n\t".IndexOf (c) == -1)
						return false;

					if (c == '\n')
						{
						i++;
						if (i == len)
							break;

						c = value[i];
						if (" \t".IndexOf (c) == -1)
							return false;
						}

					continue;
					}

				if (c == 0x7f)
					return false;
				}

			return true;
			}

		internal static bool IsToken (this string value)
			{
			foreach (var c in value)
				{
				if (c < 0x20)
					return false;

				if (c >= 0x7f)
					return false;

				if (_tspecials.IndexOf (c) > -1)
					return false;
				}

			return true;
			}

		internal static bool KeepsAlive (this NameValueCollection headers, Version version)
			{
			var comparison = StringComparison.OrdinalIgnoreCase;
			return version < HttpVersion.Version11 ? headers.Contains ("Connection", "keep-alive", comparison) : !headers.Contains ("Connection", "close", comparison);
			}

		internal static string Quote (this string value)
			{
			return String.Format ("\"{0}\"", value.Replace ("\"", "\\\""));
			}

		internal static byte[] ReadBytes (this Stream stream, int length)
			{
			var buff = new byte[length];
			var offset = 0;
			try
				{
				var nread = 0;
				while (length > 0)
					{
					nread = stream.Read (buff, offset, length);
					if (nread == 0)
						break;

					offset += nread;
					length -= nread;
					}
				}
			catch
				{
				}

			return buff.SubArray (0, offset);
			}

		internal static byte[] ReadBytes (this Stream stream, long length, int bufferLength)
			{
			using (var dest = new MemoryStream ())
				{
				try
					{
					var buff = new byte[bufferLength];
					var nread = 0;
					while (length > 0)
						{
						if (length < bufferLength)
							bufferLength = (int)length;

						nread = stream.Read (buff, 0, bufferLength);
						if (nread == 0)
							break;

						dest.Write (buff, 0, nread);
						length -= nread;
						}
					}
				catch
					{
					}

				dest.Close ();
				return dest.ToArray ();
				}
			}

		internal static void ReadBytesAsync (this Stream stream, int length, Action<byte[]> completed, Action<Exception> error)
			{
			var buff = new byte[length];
			var offset = 0;
			var retry = 0;

			AsyncCallback callback = null;
			callback = ar =>
				{
				try
					{
					var nread = stream.EndRead (ar);
					if (nread == 0 && retry < _retry)
						{
						retry++;
						stream.BeginRead (buff, offset, length, callback, null);

						return;
						}

					if (nread == length)
						{
						if (completed != null)
							completed (buff.SubArray (0, offset + nread));

						return;
						}

					retry = 0;

					offset += nread;
					length -= nread;

					stream.BeginRead (buff, offset, length, callback, null);
					}
				catch (Exception ex)
					{
					if (error != null)
						error (ex);
					}
				};

			try
				{
				stream.BeginRead (buff, offset, length, callback, null);
				}
			catch (Exception ex)
				{
				if (error != null)
					error (ex);
				}
			}

		internal static void ReadBytesAsync (this Stream stream, long length, int bufferLength, Action<byte[]> completed, Action<Exception> error)
			{
			var dest = new MemoryStream ();
			var buff = new byte[bufferLength];
			var retry = 0;

			Action<long> read = null;
			read = len =>
				{
				if (len < bufferLength)
					bufferLength = (int)len;

				stream.BeginRead (buff, 0, bufferLength, ar =>
					{
					try
						{
						var nread = stream.EndRead (ar);
						if (nread > 0)
							dest.Write (buff, 0, nread);

						if (nread == 0 && retry < _retry)
							{
							retry++;
							read (len);

							return;
							}

						if (nread == 0 || nread == len)
							{
							if (completed != null)
								{
								dest.Close ();
								completed (dest.ToArray ());
								}

							dest.Dispose ();
							return;
							}

						retry = 0;
						read (len - nread);
						}
					catch (Exception ex)
						{
						dest.Dispose ();
						if (error != null)
							error (ex);
						}
					}, null);
				};

			try
				{
				read (length);
				}
			catch (Exception ex)
				{
				dest.Dispose ();
				if (error != null)
					error (ex);
				}
			}

		internal static T[] Reverse<T> (this T[] array)
			{
			var len = array.Length;
			var ret = new T[len];

			var end = len - 1;
			for (var i = 0; i <= end; i++)
				ret[i] = array[end - i];

			return ret;
			}

		internal static IEnumerable<string> SplitHeaderValue (this string value, params char[] separators)
			{
			var len = value.Length;

			var buff = new StringBuilder (32);
			var end = len - 1;
			var escaped = false;
			var quoted = false;

			for (var i = 0; i <= end; i++)
				{
				var c = value[i];
				buff.Append (c);

				if (c == '"')
					{
					if (escaped)
						{
						escaped = false;
						continue;
						}

					quoted = !quoted;
					continue;
					}

				if (c == '\\')
					{
					if (i == end)
						break;

					if (value[i + 1] == '"')
						escaped = true;
					}

				if (Array.IndexOf (separators, c) > -1)
					{
					if (quoted)
						continue;

					buff.Length -= 1;
					yield return buff.ToString ();

					buff.Length = 0;
					}
				}

			yield return buff.ToString ();
			}

		internal static byte[] ToByteArray (this Stream stream)
			{
			using (var output = new MemoryStream ())
				{
				stream.Position = 0;
				stream.CopyTo (output, 1024);
				output.Close ();

				return output.ToArray ();
				}
			}

		internal static CompressionMethod ToCompressionMethod (this string value)
			{
#if NETCF
			foreach (CompressionMethod method in Enum2.GetValues (typeof(CompressionMethod)))
				{
#else
			foreach (CompressionMethod method in Enum.GetValues (typeof (CompressionMethod)))
#endif
				if (method.ToExtensionString () == value)
					return method;
				}

			return CompressionMethod.None;
			}

		internal static string ToExtensionString (this CompressionMethod method, params string[] parameters)
			{
			if (method == CompressionMethod.None)
				return String.Empty;

			var name = String.Format ("permessage-{0}", method.ToString ().ToLower ());

			return parameters != null && parameters.Length > 0 ? String.Format ("{0}; {1}", name, parameters.ToString ("; ")) : name;
			}

		internal static IPAddress ToIPAddress (this string value)
			{
			IPAddress addr;
#if SSHARP
			if (IPAddressTryParser.IPAddressTryParse (value, out addr))
#else
			if (IPAddress.TryParse (hostnameOrAddress, out addr))
#endif
				return addr;

			try
				{
#if SSHARP
				var addrs = DnsEx.GetHostAddresses (value);
#else
				var addrs = System.Net.Dns.GetHostAddresses (hostnameOrAddress);
#endif
				return addrs[0];
				}
			catch
				{
				return null;
				}
			}

		internal static List<TSource> ToList<TSource> (this IEnumerable<TSource> source)
			{
			return new List<TSource> (source);
			}

		internal static string ToString (this IPAddress address, bool bracketIPv6)
			{
			return bracketIPv6 && address.AddressFamily == AddressFamily.InterNetworkV6 ? String.Format ("[{0}]", address.ToString ()) : address.ToString ();
			}

		internal static ushort ToUInt16 (this byte[] source, ByteOrder sourceOrder)
			{
			return BitConverter.ToUInt16 (source.ToHostOrder (sourceOrder), 0);
			}

		internal static ulong ToUInt64 (this byte[] source, ByteOrder sourceOrder)
			{
			return BitConverter.ToUInt64 (source.ToHostOrder (sourceOrder), 0);
			}

		internal static IEnumerable<string> Trim (this IEnumerable<string> source)
			{
			foreach (var elm in source)
				yield return elm.Trim ();
			}

		internal static string TrimSlashFromEnd (this string value)
			{
			var ret = value.TrimEnd ('/');
			return ret.Length > 0 ? ret : "/";
			}

		internal static string TrimSlashOrBackslashFromEnd (this string value)
			{
			var ret = value.TrimEnd ('/', '\\');
			return ret.Length > 0 ? ret : value[0].ToString ();
			}

		internal static bool TryCreateVersion (this string versionString, out Version result)
			{
			result = null;

			try
				{
				result = new Version (versionString);
				}
			catch
				{
				return false;
				}

			return true;
			}

		/// <summary>
		/// Tries to create a new <see cref="Uri"/> for WebSocket with the specified
		/// <paramref name="uriString"/>.
		/// </summary>
		/// <returns>
		/// <c>true</c> if a <see cref="Uri"/> is successfully created; otherwise, <c>false</c>.
		/// </returns>
		/// <param name="uriString">
		/// A <see cref="string"/> that represents a WebSocket URL to try.
		/// </param>
		/// <param name="result">
		/// When this method returns, a <see cref="Uri"/> that represents a WebSocket URL,
		/// or <see langword="null"/> if <paramref name="uriString"/> is invalid.
		/// </param>
		/// <param name="message">
		/// When this method returns, a <see cref="string"/> that represents an error message,
		/// or <see cref="String.Empty"/> if <paramref name="uriString"/> is valid.
		/// </param>
		internal static bool TryCreateWebSocketUri (this string uriString, out Uri result, out string message)
			{
			result = null;
			message = null;

			var uri = uriString.ToUri ();
			if (uri == null)
				{
				message = "An invalid URI string.";
				return false;
				}

			if (!uri.IsAbsoluteUri)
				{
				message = "A relative URI.";
				return false;
				}

			var schm = uri.Scheme;
			if (!(schm == "ws" || schm == "wss"))
				{
				message = "The scheme part is not 'ws' or 'wss'.";
				return false;
				}

			var port = uri.Port;
			if (port == 0)
				{
				message = "The port part is zero.";
				return false;
				}

			if (uri.Fragment.Length > 0)
				{
				message = "It includes the fragment component.";
				return false;
				}

			result = port != -1 ? uri : new Uri (String.Format ("{0}://{1}:{2}{3}", schm, uri.Host, schm == "ws" ? 80 : 443, uri.PathAndQuery));

			return true;
			}

		internal static bool TryGetUTF8DecodedString (this byte[] bytes, out string s)
			{
			s = null;

			try
				{
				s = Encoding.UTF8.GetString (bytes);
				}
			catch
				{
				return false;
				}

			return true;
			}

		internal static bool TryGetUTF8EncodedBytes (this string s, out byte[] bytes)
			{
			bytes = null;

			try
				{
				bytes = Encoding.UTF8.GetBytes (s);
				}
			catch
				{
				return false;
				}

			return true;
			}

		internal static bool TryOpenRead (this FileInfo fileInfo, out FileStream fileStream)
			{
			fileStream = null;

			try
				{
				fileStream = fileInfo.OpenRead ();
				}
			catch
				{
				return false;
				}

			return true;
			}

#if SSHARP
		internal static bool TryOpenRead (this SSMono.IO.FileInfo fileInfo, out FileStream fileStream)
			{
			fileStream = null;

			try
				{
				fileStream = fileInfo.OpenRead ();
				}
			catch
				{
				return false;
				}

			return true;
			}
#endif

		internal static string Unquote (this string value)
			{
			var start = value.IndexOf ('"');
			if (start == -1)
				return value;

			var end = value.LastIndexOf ('"');
			if (end == start)
				return value;

			var len = end - start - 1;
			return len > 0 ? value.Substring (start + 1, len).Replace ("\\\"", "\"") : String.Empty;
			}

		internal static bool Upgrades (this NameValueCollection headers, string protocol)
			{
			var comparison = StringComparison.OrdinalIgnoreCase;
			return headers.Contains ("Upgrade", protocol, comparison) && headers.Contains ("Connection", "Upgrade", comparison);
			}

		internal static string UTF8Decode (this byte[] bytes)
			{
			try
				{
				return Encoding.UTF8.GetString (bytes);
				}
			catch
				{
				return null;
				}
			}

		internal static byte[] UTF8Encode (this string s)
			{
			return Encoding.UTF8.GetBytes (s);
			}

		internal static void WriteBytes (this Stream stream, byte[] bytes, int bufferLength)
			{
			using (var input = new MemoryStream (bytes))
				input.CopyTo (stream, bufferLength);
			}

		// From server to client
		internal static string ToResponseString (this Cookie cookie)
			{
			return cookie.Name.Length > 0 ? (cookie.Version == 0 ? cookie.toResponseStringVersion0 () : cookie.toResponseStringVersion1 ()) : String.Empty;
			}

		internal static int MaxAge (this Cookie cookie)
			{
			if (cookie.Expires == DateTime.MinValue)
				return 0;

			var expires = cookie.Expires.Kind != DateTimeKind.Local ? cookie.Expires.ToLocalTime () : cookie.Expires;

			var span = expires - DateTime.Now;
			return span > TimeSpan.Zero ? (int)span.TotalSeconds : 0;
			}

		internal static void WriteBytesAsync (this Stream stream, byte[] bytes, int bufferLength, Action completed, Action<Exception> error)
			{
			var input = new MemoryStream (bytes);

			input.CopyToAsync (stream, bufferLength, () =>
				{
				if (completed != null)
					completed ();
				input.Dispose ();
				}, ex =>
					{
					input.Dispose ();
					if (error != null)
						error (ex);
					});
			}

		#endregion

		#region Public Methods

		/// <summary>
		/// Emits the specified <see cref="EventHandler"/> delegate if it isn't <see langword="null"/>.
		/// </summary>
		/// <param name="eventHandler">
		/// A <see cref="EventHandler"/> to emit.
		/// </param>
		/// <param name="sender">
		/// An <see cref="object"/> from which emits this <paramref name="eventHandler"/>.
		/// </param>
		/// <param name="e">
		/// A <see cref="EventArgs"/> that contains no event data.
		/// </param>
		public static void Emit (this EventHandler eventHandler, object sender, EventArgs e)
			{
			if (eventHandler != null)
				eventHandler (sender, e);
			}

		/// <summary>
		/// Emits the specified <c>EventHandler&lt;TEventArgs&gt;</c> delegate
		/// if it isn't <see langword="null"/>.
		/// </summary>
		/// <param name="eventHandler">
		/// An <c>EventHandler&lt;TEventArgs&gt;</c> to emit.
		/// </param>
		/// <param name="sender">
		/// An <see cref="object"/> from which emits this <paramref name="eventHandler"/>.
		/// </param>
		/// <param name="e">
		/// A <c>TEventArgs</c> that represents the event data.
		/// </param>
		/// <typeparam name="TEventArgs">
		/// The type of the event data generated by the event.
		/// </typeparam>
		public static void Emit<TEventArgs> (this EventHandler<TEventArgs> eventHandler, object sender, TEventArgs e) where TEventArgs : EventArgs
			{
			if (eventHandler != null)
				eventHandler (sender, e);
			}

		/// <summary>
		/// Gets the description of the specified HTTP status <paramref name="code"/>.
		/// </summary>
		/// <returns>
		/// A <see cref="string"/> that represents the description of the HTTP status code.
		/// </returns>
		/// <param name="code">
		/// One of <see cref="HttpStatusCode"/> enum values, indicates the HTTP status code.
		/// </param>
		public static string GetDescription (this HttpStatusCode code)
			{
			return ((int)code).GetStatusDescription ();
			}

		/// <summary>
		/// Gets the description of the specified HTTP status <paramref name="code"/>.
		/// </summary>
		/// <returns>
		/// A <see cref="string"/> that represents the description of the HTTP status code.
		/// </returns>
		/// <param name="code">
		/// An <see cref="int"/> that represents the HTTP status code.
		/// </param>
		public static string GetStatusDescription (this int code)
			{
			switch (code)
				{
				case 100:
					return "Continue";
				case 101:
					return "Switching Protocols";
				case 102:
					return "Processing";
				case 200:
					return "OK";
				case 201:
					return "Created";
				case 202:
					return "Accepted";
				case 203:
					return "Non-Authoritative Information";
				case 204:
					return "No Content";
				case 205:
					return "Reset Content";
				case 206:
					return "Partial Content";
				case 207:
					return "Multi-Status";
				case 300:
					return "Multiple Choices";
				case 301:
					return "Moved Permanently";
				case 302:
					return "Found";
				case 303:
					return "See Other";
				case 304:
					return "Not Modified";
				case 305:
					return "Use Proxy";
				case 307:
					return "Temporary Redirect";
				case 400:
					return "Bad Request";
				case 401:
					return "Unauthorized";
				case 402:
					return "Payment Required";
				case 403:
					return "Forbidden";
				case 404:
					return "Not Found";
				case 405:
					return "Method Not Allowed";
				case 406:
					return "Not Acceptable";
				case 407:
					return "Proxy Authentication Required";
				case 408:
					return "Request Timeout";
				case 409:
					return "Conflict";
				case 410:
					return "Gone";
				case 411:
					return "Length Required";
				case 412:
					return "Precondition Failed";
				case 413:
					return "Request Entity Too Large";
				case 414:
					return "Request-Uri Too Long";
				case 415:
					return "Unsupported Media Type";
				case 416:
					return "Requested Range Not Satisfiable";
				case 417:
					return "Expectation Failed";
				case 422:
					return "Unprocessable Entity";
				case 423:
					return "Locked";
				case 424:
					return "Failed Dependency";
				case 500:
					return "Internal Server Error";
				case 501:
					return "Not Implemented";
				case 502:
					return "Bad Gateway";
				case 503:
					return "Service Unavailable";
				case 504:
					return "Gateway Timeout";
				case 505:
					return "Http Version Not Supported";
				case 507:
					return "Insufficient Storage";
				}

			return String.Empty;
			}

		/// <summary>
		/// Determines whether the specified ushort is in the range of
		/// the status code for the WebSocket connection close.
		/// </summary>
		/// <remarks>
		///   <para>
		///   The ranges are the following:
		///   </para>
		///   <list type="bullet">
		///     <item>
		///       <term>
		///       1000-2999: These numbers are reserved for definition by
		///       the WebSocket protocol.
		///       </term>
		///     </item>
		///     <item>
		///       <term>
		///       3000-3999: These numbers are reserved for use by libraries,
		///       frameworks, and applications.
		///       </term>
		///     </item>
		///     <item>
		///       <term>
		///       4000-4999: These numbers are reserved for private use.
		///       </term>
		///     </item>
		///   </list>
		/// </remarks>
		/// <returns>
		/// <c>true</c> if <paramref name="value"/> is in the range of
		/// the status code for the close; otherwise, <c>false</c>.
		/// </returns>
		/// <param name="value">
		/// A <see cref="ushort"/> to test.
		/// </param>
		public static bool IsCloseStatusCode (this ushort value)
			{
			return value > 999 && value < 5000;
			}

		/// <summary>
		/// Determines whether the specified string is enclosed in
		/// the specified character.
		/// <see cref="char"/>.
		/// </summary>
		/// <returns>
		/// <c>true</c> if <paramref name="value"/> is enclosed in
		/// <paramref name="c"/>; otherwise, <c>false</c>.
		/// </returns>
		/// <param name="value">
		/// A <see cref="string"/> to test.
		/// </param>
		/// <param name="c">
		/// A <see cref="char"/> to find.
		/// </param>
		public static bool IsEnclosedIn (this string value, char c)
			{
			return value != null && value.Length > 1 && value[0] == c && value[value.Length - 1] == c;
			}

		/// <summary>
		/// Determines whether the specified byte order is host (this computer
		/// architecture) byte order.
		/// </summary>
		/// <returns>
		/// <c>true</c> if <paramref name="order"/> is host byte order; otherwise,
		/// <c>false</c>.
		/// </returns>
		/// <param name="order">
		/// One of the <see cref="ByteOrder"/> enum values to test.
		/// </param>
		public static bool IsHostOrder (this ByteOrder order)
			{
			// true: !(true ^ true)  or !(false ^ false)
			// false: !(true ^ false) or !(false ^ true)
			return !(BitConverter.IsLittleEndian ^ (order == ByteOrder.Little));
			}

		/// <summary>
		/// Determines whether the specified IP address is a local IP address.
		/// </summary>
		/// <returns>
		/// <c>true</c> if <paramref name="address"/> is a local IP address;
		/// otherwise, <c>false</c>.
		/// <remarks>
		/// This local means NOT REMOTE for the current host.
		/// </remarks>
		/// </returns>
		/// <param name="address">
		/// A <see cref="System.Net.IPAddress"/> to test.
		/// </param>
		/// <exception cref="ArgumentNullException">
		/// <paramref name="address"/> is <see langword="null"/>.
		/// </exception>
		public static bool IsLocal (this IPAddress address)
			{
			if (address == null)
				throw new ArgumentNullException ("address");

			if (address.Equals (IPAddress.Any))
				return true;

			if (address.Equals (IPAddress.Loopback))
				return true;

#if SSHARP
#else
			if (Socket.OSSupportsIPv6)
#endif
				{
				if (address.Equals (IPAddress.IPv6Any))
					return true;

				if (address.Equals (IPAddress.IPv6Loopback))
					return true;
				}

#if SSHARP
			var numAdapters = InitialParametersClass.NumberOfEthernetInterfaces;
			for (short ix = 0; ix < numAdapters; ++ix)
				{
				var addr = CrestronEthernetHelper.GetEthernetParameter (CrestronEthernetHelper.ETHERNET_PARAMETER_TO_GET.GET_CURRENT_IP_ADDRESS, ix);
				var ipAddr = IPAddress.Parse (addr);
				if (address.Equals (ipAddr))
					return true;
				}
#else
			var host = Dns.GetHostName ();
			var addrs = Dns.GetHostAddresses (host);
			foreach (var addr in addrs)
				{
				if (address.Equals (addr))
					return true;
				}
#endif

			return false;
			}

		/// <summary>
		/// Determines whether the specified string is <see langword="null"/> or
		/// an empty string.
		/// </summary>
		/// <returns>
		/// <c>true</c> if <paramref name="value"/> is <see langword="null"/> or
		/// an empty string; otherwise, <c>false</c>.
		/// </returns>
		/// <param name="value">
		/// A <see cref="string"/> to test.
		/// </param>
		public static bool IsNullOrEmpty (this string value)
			{
			return value == null || value.Length == 0;
			}

		/// <summary>
		/// Determines whether the specified string is a predefined scheme.
		/// </summary>
		/// <returns>
		/// <c>true</c> if <paramref name="value"/> is a predefined scheme; otherwise, <c>false</c>.
		/// </returns>
		/// <param name="value">
		/// A <see cref="string"/> to test.
		/// </param>
		public static bool IsPredefinedScheme (this string value)
			{
			if (value == null || value.Length < 2)
				return false;

			var c = value[0];
			if (c == 'h')
				return value == "http" || value == "https";

			if (c == 'w')
				return value == "ws" || value == "wss";

			if (c == 'f')
				return value == "file" || value == "ftp";

			if (c == 'g')
				return value == "gopher";

			if (c == 'm')
				return value == "mailto";

			if (c == 'n')
				{
				c = value[1];
				return c == 'e' ? value == "news" || value == "net.pipe" || value == "net.tcp" : value == "nntp";
				}

			return false;
			}

		/// <summary>
		/// Determines whether the specified string is a URI string.
		/// </summary>
		/// <returns>
		/// <c>true</c> if <paramref name="value"/> may be a URI string; otherwise, <c>false</c>.
		/// </returns>
		/// <param name="value">
		/// A <see cref="string"/> to test.
		/// </param>
		public static bool MaybeUri (this string value)
			{
			if (value == null || value.Length == 0)
				return false;

			var idx = value.IndexOf (':');
			if (idx == -1)
				return false;

			if (idx >= 10)
				return false;

			var schm = value.Substring (0, idx);
			return schm.IsPredefinedScheme ();
			}

		/// <summary>
		/// Retrieves a sub-array from the specified <paramref name="array"/>.
		/// A sub-array starts at the specified element position in <paramref name="array"/>.
		/// </summary>
		/// <returns>
		/// An array of T that receives a sub-array, or an empty array of T
		/// if any problems with the parameters.
		/// </returns>
		/// <param name="array">
		/// An array of T from which to retrieve a sub-array.
		/// </param>
		/// <param name="startIndex">
		/// An <see cref="int"/> that represents the zero-based starting position of
		/// a sub-array in <paramref name="array"/>.
		/// </param>
		/// <param name="length">
		/// An <see cref="int"/> that represents the number of elements to retrieve.
		/// </param>
		/// <typeparam name="T">
		/// The type of elements in <paramref name="array"/>.
		/// </typeparam>
		public static T[] SubArray<T> (this T[] array, int startIndex, int length)
			{
			int len;
			if (array == null || (len = array.Length) == 0)
				return new T[0];

			if (startIndex < 0 || length <= 0 || startIndex + length > len)
				return new T[0];

			if (startIndex == 0 && length == len)
				return array;

			var subArray = new T[length];
			Array.Copy (array, startIndex, subArray, 0, length);

			return subArray;
			}

		/// <summary>
		/// Retrieves a sub-array from the specified <paramref name="array"/>.
		/// A sub-array starts at the specified element position in <paramref name="array"/>.
		/// </summary>
		/// <returns>
		/// An array of T that receives a sub-array, or an empty array of T
		/// if any problems with the parameters.
		/// </returns>
		/// <param name="array">
		/// An array of T from which to retrieve a sub-array.
		/// </param>
		/// <param name="startIndex">
		/// A <see cref="long"/> that represents the zero-based starting position of
		/// a sub-array in <paramref name="array"/>.
		/// </param>
		/// <param name="length">
		/// A <see cref="long"/> that represents the number of elements to retrieve.
		/// </param>
		/// <typeparam name="T">
		/// The type of elements in <paramref name="array"/>.
		/// </typeparam>
		public static T[] SubArray<T> (this T[] array, long startIndex, long length)
			{
			long len;
#if NETCF
			if (array == null || (len = array.Length) == 0)
#else
			if (array == null || (len = array.LongLength) == 0)
#endif
				return new T[0];

			if (startIndex < 0 || length <= 0 || startIndex + length > len)
				return new T[0];

			if (startIndex == 0 && length == len)
				return array;

			var subArray = new T[length];
#if NETCF
			Array.Copy (array, (int)startIndex, subArray, 0, (int)length);
#else
			Array.Copy (array, startIndex, subArray, 0, length);
#endif

			return subArray;
			}

		/// <summary>
		/// Executes the specified <see cref="Action"/> delegate <paramref name="n"/> times.
		/// </summary>
		/// <param name="n">
		/// An <see cref="int"/> is the number of times to execute.
		/// </param>
		/// <param name="action">
		/// An <see cref="Action"/> delegate that references the method(s) to execute.
		/// </param>
		public static void Times (this int n, Action action)
			{
			if (n > 0 && action != null)
				((ulong)n).times (action);
			}

		/// <summary>
		/// Executes the specified <see cref="Action"/> delegate <paramref name="n"/> times.
		/// </summary>
		/// <param name="n">
		/// A <see cref="long"/> is the number of times to execute.
		/// </param>
		/// <param name="action">
		/// An <see cref="Action"/> delegate that references the method(s) to execute.
		/// </param>
		public static void Times (this long n, Action action)
			{
			if (n > 0 && action != null)
				((ulong)n).times (action);
			}

		/// <summary>
		/// Executes the specified <see cref="Action"/> delegate <paramref name="n"/> times.
		/// </summary>
		/// <param name="n">
		/// A <see cref="uint"/> is the number of times to execute.
		/// </param>
		/// <param name="action">
		/// An <see cref="Action"/> delegate that references the method(s) to execute.
		/// </param>
		public static void Times (this uint n, Action action)
			{
			if (n > 0 && action != null)
				((ulong)n).times (action);
			}

		/// <summary>
		/// Executes the specified <see cref="Action"/> delegate <paramref name="n"/> times.
		/// </summary>
		/// <param name="n">
		/// A <see cref="ulong"/> is the number of times to execute.
		/// </param>
		/// <param name="action">
		/// An <see cref="Action"/> delegate that references the method(s) to execute.
		/// </param>
		public static void Times (this ulong n, Action action)
			{
			if (n > 0 && action != null)
				n.times (action);
			}

		/// <summary>
		/// Executes the specified <c>Action&lt;int&gt;</c> delegate <paramref name="n"/> times.
		/// </summary>
		/// <param name="n">
		/// An <see cref="int"/> is the number of times to execute.
		/// </param>
		/// <param name="action">
		/// An <c>Action&lt;int&gt;</c> delegate that references the method(s) to execute.
		/// An <see cref="int"/> parameter to pass to the method(s) is the zero-based count
		/// of iteration.
		/// </param>
		public static void Times (this int n, Action<int> action)
			{
			if (n > 0 && action != null)
				{
				for (int i = 0; i < n; i++)
					action (i);
				}
			}

		/// <summary>
		/// Executes the specified <c>Action&lt;long&gt;</c> delegate <paramref name="n"/> times.
		/// </summary>
		/// <param name="n">
		/// A <see cref="long"/> is the number of times to execute.
		/// </param>
		/// <param name="action">
		/// An <c>Action&lt;long&gt;</c> delegate that references the method(s) to execute.
		/// A <see cref="long"/> parameter to pass to the method(s) is the zero-based count
		/// of iteration.
		/// </param>
		public static void Times (this long n, Action<long> action)
			{
			if (n > 0 && action != null)
				{
				for (long i = 0; i < n; i++)
					action (i);
				}
			}

		/// <summary>
		/// Executes the specified <c>Action&lt;uint&gt;</c> delegate <paramref name="n"/> times.
		/// </summary>
		/// <param name="n">
		/// A <see cref="uint"/> is the number of times to execute.
		/// </param>
		/// <param name="action">
		/// An <c>Action&lt;uint&gt;</c> delegate that references the method(s) to execute.
		/// A <see cref="uint"/> parameter to pass to the method(s) is the zero-based count
		/// of iteration.
		/// </param>
		public static void Times (this uint n, Action<uint> action)
			{
			if (n > 0 && action != null)
				{
				for (uint i = 0; i < n; i++)
					action (i);
				}
			}

		/// <summary>
		/// Executes the specified <c>Action&lt;ulong&gt;</c> delegate <paramref name="n"/> times.
		/// </summary>
		/// <param name="n">
		/// A <see cref="ulong"/> is the number of times to execute.
		/// </param>
		/// <param name="action">
		/// An <c>Action&lt;ulong&gt;</c> delegate that references the method(s) to execute.
		/// A <see cref="ulong"/> parameter to pass to this method(s) is the zero-based count
		/// of iteration.
		/// </param>
		public static void Times (this ulong n, Action<ulong> action)
			{
			if (n > 0 && action != null)
				{
				for (ulong i = 0; i < n; i++)
					action (i);
				}
			}

		/// <summary>
		/// Converts the specified array of <see cref="byte"/> to the specified type data.
		/// </summary>
		/// <returns>
		/// A T converted from <paramref name="source"/>, or a default value of T if
		/// <paramref name="source"/> is an empty array of <see cref="byte"/> or if the
		/// type of T isn't <see cref="bool"/>, <see cref="char"/>, <see cref="double"/>,
		/// <see cref="float"/>, <see cref="int"/>, <see cref="long"/>, <see cref="short"/>,
		/// <see cref="uint"/>, <see cref="ulong"/>, or <see cref="ushort"/>.
		/// </returns>
		/// <param name="source">
		/// An array of <see cref="byte"/> to convert.
		/// </param>
		/// <param name="sourceOrder">
		/// One of the <see cref="ByteOrder"/> enum values, specifies the byte order of
		/// <paramref name="source"/>.
		/// </param>
		/// <typeparam name="T">
		/// The type of the return. The T must be a value type.
		/// </typeparam>
		/// <exception cref="ArgumentNullException">
		/// <paramref name="source"/> is <see langword="null"/>.
		/// </exception>
		public static T To<T> (this byte[] source, ByteOrder sourceOrder) where T : struct
			{
			if (source == null)
				throw new ArgumentNullException ("source");

			if (source.Length == 0)
				return default (T);

			var type = typeof(T);
			var buff = source.ToHostOrder (sourceOrder);

			return type == typeof(Boolean)
						? (T)(object)BitConverter.ToBoolean (buff, 0)
						: type == typeof(Char)
								? (T)(object)BitConverter.ToChar (buff, 0)
								: type == typeof(Double)
										? (T)(object)BitConverter.ToDouble (buff, 0)
										: type == typeof(Int16)
												? (T)(object)BitConverter.ToInt16 (buff, 0)
												: type == typeof(Int32)
														? (T)(object)BitConverter.ToInt32 (buff, 0)
														: type == typeof(Int64)
																? (T)(object)BitConverter.ToInt64 (buff, 0)
																: type == typeof(Single)
																		? (T)(object)BitConverter.ToSingle (buff, 0)
																		: type == typeof(UInt16)
																				? (T)(object)BitConverter.ToUInt16 (buff, 0)
																				: type == typeof(UInt32)
																						? (T)(object)BitConverter.ToUInt32 (buff, 0) : type == typeof(UInt64) ? (T)(object)BitConverter.ToUInt64 (buff, 0) : default (T);
			}

		/// <summary>
		/// Converts the specified <paramref name="value"/> to an array of <see cref="byte"/>.
		/// </summary>
		/// <returns>
		/// An array of <see cref="byte"/> converted from <paramref name="value"/>.
		/// </returns>
		/// <param name="value">
		/// A T to convert.
		/// </param>
		/// <param name="order">
		/// One of the <see cref="ByteOrder"/> enum values, specifies the byte order of the return.
		/// </param>
		/// <typeparam name="T">
		/// The type of <paramref name="value"/>. The T must be a value type.
		/// </typeparam>
		public static byte[] ToByteArray<T> (this T value, ByteOrder order) where T : struct
			{
			var type = typeof(T);
			var bytes = type == typeof(Boolean)
								? BitConverter.GetBytes ((Boolean)(object)value)
								: type == typeof(Byte)
										? new byte[] {(Byte)(object)value}
										: type == typeof(Char)
												? BitConverter.GetBytes ((Char)(object)value)
												: type == typeof(Double)
														? BitConverter.GetBytes ((Double)(object)value)
														: type == typeof(Int16)
																? BitConverter.GetBytes ((Int16)(object)value)
																: type == typeof(Int32)
																		? BitConverter.GetBytes ((Int32)(object)value)
																		: type == typeof(Int64)
																				? BitConverter.GetBytes ((Int64)(object)value)
																				: type == typeof(Single)
																						? BitConverter.GetBytes ((Single)(object)value)
																						: type == typeof(UInt16)
																								? BitConverter.GetBytes ((UInt16)(object)value)
																								: type == typeof(UInt32)
																										? BitConverter.GetBytes ((UInt32)(object)value)
																										: type == typeof(UInt64) ? BitConverter.GetBytes ((UInt64)(object)value) : WebSocket.EmptyBytes;

			if (bytes.Length > 1 && !order.IsHostOrder ())
				Array.Reverse (bytes);

			return bytes;
			}

		/// <summary>
		/// Converts the order of elements in the specified byte array to
		/// host (this computer architecture) byte order.
		/// </summary>
		/// <returns>
		///   <para>
		///   An array of <see cref="byte"/> converted from
		///   <paramref name="source"/>.
		///   </para>
		///   <para>
		///   Or <paramref name="source"/> if the number of elements in it
		///   is less than 2 or <paramref name="sourceOrder"/> is same as
		///   host byte order.
		///   </para>
		/// </returns>
		/// <param name="source">
		/// An array of <see cref="byte"/> to convert.
		/// </param>
		/// <param name="sourceOrder">
		///   <para>
		///   One of the <see cref="ByteOrder"/> enum values.
		///   </para>
		///   <para>
		///   It specifies the order of elements in <paramref name="source"/>.
		///   </para>
		/// <paramref name="source"/>.
		/// </param>
		/// <exception cref="ArgumentNullException">
		/// <paramref name="source"/> is <see langword="null"/>.
		/// </exception>
		public static byte[] ToHostOrder (this byte[] source, ByteOrder sourceOrder)
			{
			if (source == null)
				throw new ArgumentNullException ("source");

			if (source.Length < 2)
				return source;

			return !sourceOrder.IsHostOrder () ? source.Reverse () : source;
			}

		/// <summary>
		/// Converts the specified array to a <see cref="string"/>.
		/// </summary>
		/// <returns>
		///   <para>
		///   A <see cref="string"/> converted by concatenating each element of
		///   <paramref name="array"/> across <paramref name="separator"/>.
		///   </para>
		///   <para>
		///   An empty string if <paramref name="array"/> is an empty array.
		///   </para>
		/// </returns>
		/// <param name="array">
		/// An array of T to convert.
		/// </param>
		/// <param name="separator">
		/// A <see cref="string"/> used to separate each element of
		/// <paramref name="array"/>.
		/// </param>
		/// <typeparam name="T">
		/// The type of elements in <paramref name="array"/>.
		/// </typeparam>
		/// <exception cref="ArgumentNullException">
		/// <paramref name="array"/> is <see langword="null"/>.
		/// </exception>
		public static string ToString<T> (this T[] array, string separator)
			{
			if (array == null)
				throw new ArgumentNullException ("array");

			var len = array.Length;
			if (len == 0)
				return String.Empty;

			if (separator == null)
				separator = String.Empty;

			var buff = new StringBuilder (64);

			for (var i = 0; i < len - 1; i++)
				buff.AppendFormat ("{0}{1}", array[i], separator);

			buff.Append (array[len - 1].ToString ());
			return buff.ToString ();
			}

		/// <summary>
		/// Converts the specified string to a <see cref="Uri"/>.
		/// </summary>
		/// <returns>
		///   <para>
		///   A <see cref="Uri"/> converted from <paramref name="value"/>.
		///   </para>
		///   <para>
		///   <see langword="null"/> if the conversion has failed.
		///   </para>
		/// </returns>
		/// <param name="value">
		/// A <see cref="string"/> to convert.
		/// </param>
		public static Uri ToUri (this string value)
			{
			Uri ret;
			Uri.TryCreate (value, value.MaybeUri () ? UriKind.Absolute : UriKind.Relative, out ret);

			return ret;
			}

		/// <summary>
		/// URL-decodes the specified <see cref="string"/>.
		/// </summary>
		/// <returns>
		/// A <see cref="string"/> that receives the decoded string, or the <paramref name="value"/>
		/// if it's <see langword="null"/> or empty.
		/// </returns>
		/// <param name="value">
		/// A <see cref="string"/> to decode.
		/// </param>
		public static string UrlDecode (this string value)
			{
			return value != null && value.Length > 0 ? HttpUtility.UrlDecode (value) : value;
			}

		/// <summary>
		/// URL-encodes the specified <see cref="string"/>.
		/// </summary>
		/// <returns>
		/// A <see cref="string"/> that receives the encoded string, or <paramref name="value"/>
		/// if it's <see langword="null"/> or empty.
		/// </returns>
		/// <param name="value">
		/// A <see cref="string"/> to encode.
		/// </param>
		public static string UrlEncode (this string value)
			{
			return value != null && value.Length > 0 ? HttpUtility.UrlEncode (value) : value;
			}

#if !CLIENT
		/// <summary>
		/// Writes and sends the specified <paramref name="content"/> data with the specified
		/// <see cref="HttpListenerResponse"/>.
		/// </summary>
		/// <param name="response">
		/// A <see cref="HttpListenerResponse"/> that represents the HTTP response
		/// used to write the content data.
		/// </param>
		/// <param name="content">
		/// An array of <see cref="byte"/> that represents the content data to send.
		/// </param>
		/// <exception cref="ArgumentNullException">
		///   <para>
		///   <paramref name="response"/> is <see langword="null"/>.
		///   </para>
		///   <para>
		///   -or-
		///   </para>
		///   <para>
		///   <paramref name="content"/> is <see langword="null"/>.
		///   </para>
		/// </exception>
		public static void WriteContent (this HttpListenerResponse response, byte[] content)
			{
			if (response == null)
				throw new ArgumentNullException ("response");

			if (content == null)
				throw new ArgumentNullException ("content");

#if NETCF
			var len = content.Length;
#else
			var len = content.LongLength;
#endif
			if (len == 0)
				{
				response.Close ();
				return;
				}

			response.ContentLength64 = len;
			var output = response.OutputStream;
			if (len <= Int32.MaxValue)
				output.Write (content, 0, (int)len);
			else
				output.WriteBytes (content, 1024);

			output.Close ();
			}

		/// <summary>
		/// Writes the specified <paramref name="content"/> data with the specified
		/// <see cref="HttpListenerResponse"/>.
		/// </summary>
		/// <param name="response">
		/// A <see cref="HttpListenerResponse"/> that represents the HTTP response
		/// used to write the content data.
		/// </param>
		/// <param name="content">
		/// A string <see cref="string"/> that represents the content data to write.
		/// </param>
		/// <exception cref="ArgumentNullException">
		/// <paramref name="response"/> is <see langword="null"/>.
		/// </exception>
		public static void WriteContent (this HttpListenerResponse response, string content)
			{
			if (response == null)
				throw new ArgumentNullException ("response");

			if (string.IsNullOrEmpty (content))
				return;

			var data = response.ContentEncoding.GetBytes (content);
			var output = response.OutputStream;
			response.ContentLength64 = data.Length;
			output.Write (data, 0, data.Length);
			output.Close ();
			}
#endif

		#endregion
		}
	}