internal char[] ConsumeCharacterReference(char?additionalAllowedCharacter, bool inAttribute)
{
if (reader.IsEmpty())
{
return(null);
}
if (additionalAllowedCharacter != null && additionalAllowedCharacter == reader.Current())
{
return(null);
}
if (reader.MatchesAny('\t', '\n', '\r', '\f', ' ', '<', '&'))
{
return(null);
}
reader.Mark();
if (reader.MatchConsume("#"))
{
// numbered
bool isHexMode = reader.MatchConsumeIgnoreCase("X");
string numRef = isHexMode ? reader.ConsumeHexSequence() : reader.ConsumeDigitSequence();
if (numRef.Length == 0)
{
// didn't match anything
CharacterReferenceError("numeric reference with no numerals");
reader.RewindToMark();
return(null);
}
if (!reader.MatchConsume(";"))
{
CharacterReferenceError("missing semicolon");
}
// missing semi
int charval = -1;
try
{
int @base = isHexMode ? 16 : 10;
charval = Convert.ToInt32(numRef, @base);
}
catch (FormatException)
{
}
// skip
if (charval == -1 || (charval >= 0xD800 && charval <= 0xDFFF) || charval > 0x10FFFF)
{
CharacterReferenceError("character outside of valid range");
return(new char[] { replacementChar });
}
else
{
// todo: implement number replacement table
// todo: check for extra illegal unicode points as parse errors
return(char.ConvertFromUtf32(charval).ToCharArray());
}
}
else
{
// named
// get as many letters as possible, and look for matching entities.
string nameRef = reader.ConsumeLetterThenDigitSequence();
bool looksLegit = reader.Matches(';');
// found if a base named entity without a ;, or an extended entity with the ;.
bool found = (Entities.IsBaseNamedEntity(nameRef) || (Entities.IsNamedEntity(nameRef) && looksLegit));
if (!found)
{
reader.RewindToMark();
if (looksLegit)
{
// named with semicolon
CharacterReferenceError(string.Format("invalid named referenece '{0}'", nameRef));
}
return(null);
}
if (inAttribute && (reader.MatchesLetter() || reader.MatchesDigit() || reader.MatchesAny('=', '-', '_')))
{
// don't want that to match
reader.RewindToMark();
return(null);
}
if (!reader.MatchConsume(";"))
{
CharacterReferenceError("missing semicolon");
}
// missing semi
int charval = Entities.GetCharacterByName(nameRef);
return(char.ConvertFromUtf32(charval).ToCharArray());
}
}