Apple's CFHash algorithm for strings in Ruby

gistfile1.rb

# Why? Why not!

def cfhash string
  result = string.length
  max = 2 ** 32
  string.each_codepoint do |cp|
    result = ((result * 257) % max) + cp
  end
  return (result + (result << (string.length & 31))) % max
end

This still isn't quite right. For some strings it's correct, for others it's wrong.

(Notably, it will be wrong for strings longer than 96 characters, because that's special-cased in the original algorithm. But I don't need to cover that case for what I'm using this for.)