Procedural Version of Circular Buffer

circular_buffer_procedural.rb

class CircularBuffer
  class BufferEmptyException < IOError; end
  class BufferFullException < IOError; end
  attr_reader :data

  def initialize(size)
    @data = Array.new(size)
    @read_index = 0
    @write_index = 0
  end

  def read
    raise BufferEmptyException if buffer_empty?
    @read_index = 0 if @read_index == data.size
    value = data[@read_index]
    data[@read_index] = nil
    @read_index += 1
    value
  end

  def write(element)
    insert(element) { raise BufferFullException }
  end

  def write!(element)
    insert(element) { @read_index += 1 }
  end

  def clear
    data.fill(nil)
  end

  private

  def insert(element, &block)
    return unless element
    block.call if buffer_full?
    @write_index = 0 if @write_index == data.size
    data[@write_index] = element
    @write_index += 1
  end

  def buffer_empty?
    data.compact.empty?
  end

  def buffer_full?
    data.none?(&:nil?)
  end
end