'Read compressed data from the underlying transport, then
decompress it and append it to the internal StringIO read buffer'

def readComp(self, sz):

    zbuf = self.__trans.read(sz)
    zbuf = (self._zcomp_read.unconsumed_tail + zbuf)
    buf = self._zcomp_read.decompress(zbuf)
    self.bytes_in += len(zbuf)
    self.bytes_in_comp += len(buf)
    old = self.__rbuf.read()
    self.__rbuf = StringIO((old + buf))
    if ((len(old) + len(buf)) == 0):
        return False
    return True
