System.Text.Normalization.Normalize C# (CSharp) Method

        internal String Normalize(String strInput)
        {
            if (strInput == null)
                throw new ArgumentNullException( "strInput",
                    Environment.GetResourceString("ArgumentNull_String"));

            // Guess our buffer size first
            int iLength = GuessLength(strInput);

            // Don't break for empty strings (only possible for D & KD and not really possible at that)
            if (iLength == 0) return String.Empty;

            // Someplace to stick our buffer
            char[] cBuffer = null;

            int iError = ERROR_INSUFFICIENT_BUFFER;
            while (iError == ERROR_INSUFFICIENT_BUFFER)
            {
                // (re)allocation buffer and normalize string
                cBuffer = new char[iLength];
                iLength = nativeNormalizationNormalizeString(
                    normalizationForm, ref iError,
                    strInput, strInput.Length, cBuffer, cBuffer.Length);

                // Could have an error (actually it'd be quite hard to have an error here)
                if (iError != ERROR_SUCCESS)
                {
                    switch(iError)
                    {
                        // Do appropriate stuff for the individual errors:
                        case ERROR_INSUFFICIENT_BUFFER:
                            BCLDebug.Assert(iLength > cBuffer.Length, "Buffer overflow should have iLength > cBuffer.Length");
                            continue;
                        case ERROR_NO_UNICODE_TRANSLATION:
                            // Illegal code point or order found.  Ie: FFFE or D800 D800, etc.
                            throw new ArgumentException(
                                Environment.GetResourceString("Argument_InvalidCharSequence", iLength ),
                                "strInput");
                        case ERROR_NOT_ENOUGH_MEMORY:
                            throw new OutOfMemoryException(
                                Environment.GetResourceString("Arg_OutOfMemoryException"));
                        case ERROR_INVALID_PARAMETER:
                            // Shouldn't have invalid parameters here unless we have a bug, drop through...
                        default:
                            // We shouldn't get here...
                            throw new InvalidOperationException(
                                Environment.GetResourceString("UnknownError_Num", iError));
                    }
                }
            }

            // Copy our buffer into our new string, which will be the appropriate size
            String strReturn = new String(cBuffer, 0, iLength);

            // Return our output string
            return strReturn;
        }

		public static string Normalize (string source, NormalizationForm normalizationForm)
		{
			switch (normalizationForm) {
			default:
				return Normalization.Normalize (source, 0);
			case NormalizationForm.FormD:
				return Normalization.Normalize (source, 1);
			case NormalizationForm.FormKC:
				return Normalization.Normalize (source, 2);
			case NormalizationForm.FormKD:
				return Normalization.Normalize (source, 3);
			}
		}