elixir driver for cassandra/scylla [d5b39161]

  defmodule ShardCalculator do
    @min_token -1 <<< 63
    @token_max 1 <<< 64

    def calculate_shard(token, ignore_msb, nr_shards) do
      # Bias the token
      biased_token = token - @min_token

      # Left shift by ignore_msb bits
      biased_token = biased_token <<< ignore_msb

      # Multiply by number of shards and perform truncating division
      shard = div(biased_token * nr_shards, @token_max)
      shard
    end
  end

  defmodule ShardCalculator do
    @min_token -1 <<< 63
    @token_max 1 <<< 64

    def calculate_shard(token, ignore_msb, nr_shards) do
      token = token - @min_token
      token = token <<< ignore_msb

      tok_lo = token &&& 0xFFFFFFFF
      tok_hi = token >>> 32

      mul1 = tok_lo * nr_shards
      mul2 = tok_hi * nr_shards

      sum = (mul1 >>> 32) + mul2
      sum >>> 32
    end
  end