def __init__(self):
        vstruct.VStruct.__init__(self)
        self.SFreeListEntry = SINGLE_LIST_ENTRY()
        self.Reserved = v_ptr32()
        self.SizeIndexAndPadding = v_uint32()
        self.Signature = v_uint32()
        self.EncodedOffsets = HEAP_USERDATA_OFFSETS()
        self.BusyBitmap = RTL_BITMAP()
        self.BitmapData = vstruct.VArray([ v_uint32() for i in xrange(1) ])