LB method

  1. @override
Token? LB(
  1. int k
)
override

Implementation

@override
Token? LB(int k) {
  if (k == 0 || (p - k) < 0) return null;

  var i = p;
  var n = 1;
  // find k good tokens looking backwards
  while (n <= k && i > 0) {
    // skip off-channel tokens
    i = previousTokenOnChannel(i - 1, channel);
    n++;
  }
  if (i < 0) return null;
  return tokens[i];
}