private NFAState ParseAtomModifier(NFAState start, NFAState end)
{
int min = 0;
int max = -1;
int firstPos = _pos;
// Read min and max
switch (ReadChar())
{
case '?':
min = 0;
max = 1;
break;
case '*':
min = 0;
max = -1;
break;
case '+':
min = 1;
max = -1;
break;
case '{':
min = ReadNumber();
max = min;
if (PeekChar(0) == ',')
{
ReadChar(',');
max = -1;
if (PeekChar(0) != '}')
{
max = ReadNumber();
}
}
ReadChar('}');
if (max == 0 || (max > 0 && min > max))
{
throw new RegExpException(
RegExpException.ErrorType.INVALID_REPEAT_COUNT,
firstPos,
_pattern);
}
break;
default:
throw new RegExpException(
RegExpException.ErrorType.UNEXPECTED_CHARACTER,
_pos - 1,
_pattern);
}
// Read possessive or reluctant modifiers
if (PeekChar(0) == '?')
{
throw new RegExpException(
RegExpException.ErrorType.UNSUPPORTED_SPECIAL_CHARACTER,
_pos,
_pattern);
}
else if (PeekChar(0) == '+')
{
throw new RegExpException(
RegExpException.ErrorType.UNSUPPORTED_SPECIAL_CHARACTER,
_pos,
_pattern);
}
// Handle supported repeaters
if (min == 0 && max == 1)
{
return(start.AddOut(new NFAEpsilonTransition(end)));
}
else if (min == 0 && max == -1)
{
if (end.Outgoing.Length == 0)
{
end.MergeInto(start);
}
else
{
end.AddOut(new NFAEpsilonTransition(start));
}
return(start);
}
else if (min == 1 && max == -1)
{
if (start.Outgoing.Length == 1 &&
end.Outgoing.Length == 0 &&
end.Incoming.Length == 1 &&
start.Outgoing[0] == end.Incoming[0])
{
end.AddOut(start.Outgoing[0].Copy(end));
}
else
{
end.AddOut(new NFAEpsilonTransition(start));
}
return(end);
}
else
{
throw new RegExpException(
RegExpException.ErrorType.INVALID_REPEAT_COUNT,
firstPos,
_pattern);
}
}
public NFANonWordTransition(NFAState state) : base(state)
{
}
public override NFATransition Copy(NFAState state)
{
return(new NFANonWordTransition(state));
}
public override NFATransition Copy(NFAState state)
{
return(new NFAWhitespaceTransition(state));
}
public NFANonWhitespaceTransition(NFAState state) : base(state)
{
}
public override NFATransition Copy(NFAState state)
{
return(new NFADigitTransition(state));
}
public NFANonDigitTransition(NFAState state) : base(state)
{
}
public override NFATransition Copy(NFAState state)
{
return(new NFACharTransition(_match, state));
}
public NFADotTransition(NFAState state) : base(state)
{
}
public NFACharTransition(char match, NFAState state) : base(state)
{
_match = match;
}
public override NFATransition Copy(NFAState state)
{
return(new NFAEpsilonTransition(state));
}
public NFAEpsilonTransition(NFAState state) : base(state)
{
}
public abstract NFATransition Copy(NFAState state);
protected NFATransition(NFAState state)
{
this.State = state;
this.State.AddIn(this);
}