/// <summary>
///
/// </summary>
/// <param name="reader"></param>
/// <returns></returns>
public static ABNF_Repetition Parse(System.IO.StringReader reader)
{
if (reader == null)
{
throw new ArgumentNullException("reader");
}
/*
* repetition = [repeat] element
* repeat = 1*DIGIT / (*DIGIT "*" *DIGIT)
* element = rulename / group / option / char-val / num-val / prose-val
*/
int min = 0;
int max = int.MaxValue;
// --- range ------------------------------------
if (char.IsDigit((char)reader.Peek()))
{
StringBuilder minString = new StringBuilder();
while (char.IsDigit((char)reader.Peek()))
{
minString.Append((char)reader.Read());
}
min = Convert.ToInt32(minString.ToString());
}
if (reader.Peek() == '*')
{
reader.Read();
}
if (char.IsDigit((char)reader.Peek()))
{
StringBuilder maxString = new StringBuilder();
while (char.IsDigit((char)reader.Peek()))
{
maxString.Append((char)reader.Read());
}
max = Convert.ToInt32(maxString.ToString());
}
//-----------------------------------------------
// End of stream reached.
if (reader.Peek() == -1)
{
return(null);
}
// We have rulename.
else if (char.IsLetter((char)reader.Peek()))
{
return(new ABNF_Repetition(min, max, ABNF_RuleName.Parse(reader)));
}
// We have group.
else if (reader.Peek() == '(')
{
return(new ABNF_Repetition(min, max, ABFN_Group.Parse(reader)));
}
// We have option.
else if (reader.Peek() == '[')
{
return(new ABNF_Repetition(min, max, ABNF_Option.Parse(reader)));
}
// We have char-val.
else if (reader.Peek() == '\"')
{
return(new ABNF_Repetition(min, max, ABNF_CharVal.Parse(reader)));
}
// We have num-val.
else if (reader.Peek() == '%')
{
// Eat '%'.
reader.Read();
if (reader.Peek() == 'd')
{
return(new ABNF_Repetition(min, max, ABNF_DecVal.Parse(reader)));
}
else
{
throw new ParseException("Invalid 'num-val' value '" + reader.ReadToEnd() + "'.");
}
}
// We have prose-val.
else if (reader.Peek() == '<')
{
return(new ABNF_Repetition(min, max, ABNF_ProseVal.Parse(reader)));
}
return(null);
}