/// <summary>
/// Called once an & character is being seen.
/// </summary>
/// <returns>The entity token.</returns>
String CharacterReference()
{
var c = GetNext();
var start = StringBuffer.Length;
var hex = false;
var numeric = c == Symbols.Num;
if (numeric)
{
c = GetNext();
hex = c == 'x' || c == 'X';
if (hex)
{
c = GetNext();
while (c.IsHex())
{
StringBuffer.Append(c);
c = GetNext();
}
}
else
{
while (c.IsDigit())
{
StringBuffer.Append(c);
c = GetNext();
}
}
}
else if (c.IsXmlNameStart())
{
do
{
StringBuffer.Append(c);
c = GetNext();
}while (c.IsXmlName());
}
if (c == Symbols.Semicolon && StringBuffer.Length > start)
{
var length = StringBuffer.Length - start;
var content = StringBuffer.ToString(start, length);
StringBuffer.Remove(start, length);
if (numeric)
{
var number = numeric ? content.FromHex() : content.FromDec();
if (!number.IsValidAsCharRef())
{
throw XmlParseError.CharacterReferenceInvalidNumber.At(_position);
}
return(number.ConvertFromUtf32());
}
else
{
var entity = _resolver.GetSymbol(content);
if (String.IsNullOrEmpty(entity))
{
throw XmlParseError.CharacterReferenceInvalidCode.At(_position);
}
return(entity);
}
}
throw XmlParseError.CharacterReferenceNotTerminated.At(GetCurrentPosition());
}
