pettyjamesm

require 'monitor'
class Semaphore
  def initialize(maxval = nil)
    maxval = maxval.to_i unless maxval.nil?
    raise ArgumentError.new("Semaphores must use a positive maximum value or have no maximum!") if maxval and maxval <= 0
    @max   = maxval || -1
    @count = 0
    @mon   = Monitor.new
    @dwait = @mon.new_cond
    @uwait = @mon.new_cond