docs: function(string, start, end) {
    var crc = 0
    var x = 0;
    var y = 0;
    crc = crc ^ (-1);
  
    for(var i = start, iTop = end; i < iTop;i++) {
    	y = (crc ^ string[i]) & 0xFF;
      x = table[y];
    	crc = (crc >>> 8) ^ x;
    }
  
    return crc ^ (-1);
  }