Fowler-Noll-Vo hash
gem install fnv
require "fnv"
FNV.new.fnv1a_64("blah") => 14233852691173593346
Supported hashes are fnv1_32, fnv1_64, fnv1a_32, and fnv1a_64.
There are other implementations but they use C.
Test cases were taken from here.