/**
* Checks if this NFA matches the specified input text. The
* matching will be performed from position zero (0) in the
* buffer. This method will not read any characters from the
* stream, just peek ahead.
*
* @param buffer the input buffer to check
* @param match the token match to update
*
* @return the number of characters matched, or
* zero (0) if no match was found
*
* @throws IOException if an I/O error occurred
*/
public int Match(ReaderBuffer buffer, TokenMatch match)
{
int length = 0;
int pos = 1;
int peekChar;
NFAState state;
// The first step of the match loop has been unrolled and
// optimized for performance below.
queue.Clear();
peekChar = buffer.Peek(0);
if (0 <= peekChar && peekChar < 128)
{
state = initialChar[peekChar];
if (state != null)
{
queue.AddLast(state);
}
}
if (peekChar >= 0)
{
initial.MatchTransitions((char)peekChar, queue, true);
}
queue.MarkEnd();
peekChar = buffer.Peek(1);
// The remaining match loop processes all subsequent states
while (!queue.Empty)
{
if (queue.Marked)
{
pos++;
peekChar = buffer.Peek(pos);
queue.MarkEnd();
}
state = queue.RemoveFirst();
if (state.value != null)
{
match.Update(pos, state.value);
}
if (peekChar >= 0)
{
state.MatchTransitions((char)peekChar, queue, false);
}
}
return(length);
}
