System.Uri.Uri.UnescapeDataString C# (CSharp) Method

		public static string UnescapeDataString (string stringToUnescape)
		{
			if (stringToUnescape == null)
				throw new ArgumentNullException ("stringToUnescape");

			if (stringToUnescape.IndexOf ('%') == -1 && stringToUnescape.IndexOf ('+') == -1)
				return stringToUnescape;

			StringBuilder output = new StringBuilder ();
			long len = stringToUnescape.Length;
			MemoryStream bytes = new MemoryStream ();
			int xchar;

			for (int i = 0; i < len; i++) {
				if (stringToUnescape [i] == '%' && i + 2 < len && stringToUnescape [i + 1] != '%') {
					if (stringToUnescape [i + 1] == 'u' && i + 5 < len) {
						if (bytes.Length > 0) {
							output.Append (GetChars (bytes, Encoding.UTF8));
							bytes.SetLength (0);
						}

						xchar = GetChar (stringToUnescape, i + 2, 4);
						if (xchar != -1) {
							output.Append ((char) xchar);
							i += 5;
						}
						else {
							output.Append ('%');
						}
					}
					else if ((xchar = GetChar (stringToUnescape, i + 1, 2)) != -1) {
						bytes.WriteByte ((byte) xchar);
						i += 2;
					}
					else {
						output.Append ('%');
					}
					continue;
				}

				if (bytes.Length > 0) {
					output.Append (GetChars (bytes, Encoding.UTF8));
					bytes.SetLength (0);
				}

				output.Append (stringToUnescape [i]);
			}

			if (bytes.Length > 0) {
				output.Append (GetChars (bytes, Encoding.UTF8));
			}

			bytes = null;
			return output.ToString ();
		}