class FastCache::CRC32

  def initialize(string = nil)
    @crc = 0xFFFFFFFF
    self << string if string
  end

  def <<(string)
    string.size.times do |i|
      @crc ^= string[i]
      8.times do
        if (@crc & 1).zero?
          @crc >>= 1
        else
          @crc = (@crc >> 1) ^ 0xEDB88320
        end
      end
    end
    self
  end

  def digest
    [@crc ^ 0xFFFFFFFF].pack('N')
  end

  def hexdigest
    (@crc ^ 0xFFFFFFFF).to_s(16)
  end

end