cyclic_barrier.rb

# encoding: utf-8

class CyclicBarrier
  def initialize(n)
    @n = n
    @await_count = 0
    @mutex = Mutex.new
    @var = ConditionVariable.new
  end

  def await
    @mutex.synchronize do
      @await_count += 1
      if @await_count == @n then
        @var.broadcast
      else
        @var.wait(@mutex)
      end
    end
  end
end