text: from rpython.rtyper.lltypesystem import rffi
  
  from pypy.interpreter.error import OperationError
  from pypy.module.mmap.interp_mmap import W_MMap
  
  def address_of_buffer(space, w_obj):
      if space.config.objspace.usemodules.mmap:
          mmap = space.interp_w(W_MMap, w_obj)
          address = rffi.cast(rffi.SIZE_T, mmap.mmap.data)
          return space.newtuple([space.wrap(address),
                                 space.wrap(mmap.mmap.size)])
      else:
          raise OperationError(space.w_TypeError, space.wrap(
              "cannot get address of buffer"))
  