Collision detection is far cheaper. One method: Simply add up all the bytes of all seen placenames while running your fast algorithm. This is effectively

Collision detection is far cheaper. One method: Simply add up all the bytes of all seen placenames while running your fast algorithm. This is effectively a checksum of all bytes of placename data. Then at the end, calculate the 'correct' name-sum (which can be done cheaply). If it doesn't match, a collision occurred.