getLine method

int getLine (int offset)

Gets the 0-based line corresponding to offset.

Implementation 

int getLine(int offset) {
  if (offset < 0) {
    throw new RangeError("Offset may not be negative, was $offset.");
  } else if (offset > length) {
    throw new RangeError("Offset $offset must not be greater than the number "
        "of characters in the file, $length.");
  }

  if (offset < _lineStarts.first) return -1;
  if (offset >= _lineStarts.last) return _lineStarts.length - 1;

  if (_isNearCachedLine(offset)) return _cachedLine;

  _cachedLine = _binarySearch(offset) - 1;
  return _cachedLine;
}