A simple ring buffer for Ruby.

ringbuffer.rb

class RingBuffer < Array
  attr_reader :max_size
 
  def initialize(max_size, enum = nil)
    @max_size = max_size
    enum.each { |e| self << e } if enum
  end
 
  def <<(el)
    if self.size < @max_size || @max_size.nil?
      super
    else
      self.shift
      self.push(el)
    end
  end
 
  alias :push :<<
end

Also check out this threadsafe one http://git.io/8RZjeA