# frozen_string_literal: true

# Use CityHash for fast hashing if it is available; use Digest::MD5 otherwise
begin
  require "cityhash"
rescue LoadError
  unless RUBY_PLATFORM == "java"
    warn(<<-NOTICE)
      ** Notice: CityHash was not loaded. **

      For optimal performance, use of the cityhash gem is recommended.

      Run the following command, or add it to your Gemfile:

        gem install cityhash
    NOTICE
  end

  require "digest/md5"
end

module IdentityCache
  module CacheHash
    if defined?(CityHash)

      def memcache_hash(key) # :nodoc:
        CityHash.hash64(key)
      end
    else

      def memcache_hash(key) # :nodoc:
        a = Digest::MD5.digest(key).unpack("LL")
        (a[0] << 32) | a[1]
      end
    end
  end
end