public static string TryConvertPresentationToValue([NotNull] string value,
StringLiteralPresentationForm presentationForm)
{
var builder = new StringBuilder(value.Length);
for (var i = 0; i < value.Length;)
{
var presentationLength = GetCharPresentationLength(value, i);
if (presentationLength == -1)
{
return(null);
}
if (presentationLength == 1)
{
builder.Append(value[i++]);
}
else
{
string charResult;
var presentation = value.Substring(i, presentationLength);
if (!TryConvertPresentationToValue(presentation, presentationForm,
out charResult))
{
return(null);
}
builder.Append(charResult);
i += presentationLength;
}
}
return(builder.ToString());
}
public static bool TryConvertPresentationToValue(
[NotNull] string charPresentation, StringLiteralPresentationForm presentationForm, out string result)
{
if (charPresentation.Length == 1)
{
var ch = charPresentation[0];
if (ch == '\\' || ch == '\n')
{
goto Fail;
}
if (ch == '\"' && presentationForm == StringLiteralPresentationForm.DOUBLE_QUOTED)
{
goto Fail;
}
if (ch == '\'' && presentationForm == StringLiteralPresentationForm.SINGLE_QUOTED)
{
goto Fail;
}
result = charPresentation;
return(true);
}
switch (charPresentation)
{
case @"\'":
result = "\'";
return(true);
case @"\""":
result = "\"";
return(true);
case @"\\":
result = "\\";
return(true);
case @"\0":
result = "\0";
return(true);
case @"\b":
result = "\b";
return(true);
case @"\f":
result = "\f";
return(true);
case @"\n":
result = "\n";
return(true);
case @"\r":
result = "\r";
return(true);
case @"\t":
result = "\t";
return(true);
case @"\v":
result = "\v";
return(true);
}
if (charPresentation.StartsWith(@"\x", StringComparison.Ordinal) ||
charPresentation.StartsWith(@"\u", StringComparison.Ordinal))
{
int utf;
charPresentation = charPresentation.Substring(2);
if (int.TryParse(charPresentation, NumberStyles.HexNumber, NumberFormatInfo.InvariantInfo, out utf))
{
if (utf < 0x000000 || utf > 0x10ffff)
{
goto Fail;
}
if (utf >= 0x00d800 && utf <= 0x00dfff)
{
result = new string(Convert.ToChar(utf), 1);
return(true);
}
try
{
result = Char.ConvertFromUtf32(utf);
}
catch (ArgumentOutOfRangeException)
{
goto Fail;
}
return(true);
}
}
else if (charPresentation.Length == 2)
{
// \ NonEscapeCharacter
result = charPresentation[1].ToString(CultureInfo.InvariantCulture);
return(true);
}
Fail:
result = null;
return(false);
}
