def __init__(self):
        vstruct.VStruct.__init__(self)
        self.CompressionFormatAndEngine = v_uint16()
        self.CompressionUnitShift = v_uint8()
        self.ChunkShift = v_uint8()
        self.ClusterShift = v_uint8()
        self.Reserved = v_uint8()
        self.NumberOfChunks = v_uint16()
        self.CompressedChunkSizes = vstruct.VArray([ v_uint32() for i in xrange(1) ])