def _reformat(p, buf):
    """ Apply format of ``p`` to data in 1-d array ``buf``. """
    if numpy.ndim(buf) != 1:
        raise ValueError("Buffer ``buf`` must be 1-d.")
    if hasattr(p, 'keys'):
        ans = _gvar.BufferDict(p)
        if ans.size != len(buf):
            raise ValueError(       #
                "p, buf size mismatch: %d, %d"%(ans.size, len(buf)))
        ans = _gvar.BufferDict(ans, buf=buf)
    else:
        if numpy.size(p) != len(buf):
            raise ValueError(       #
                "p, buf size mismatch: %d, %d"%(numpy.size(p), len(buf)))
        ans = numpy.array(buf).reshape(numpy.shape(p))
    return ans
Apply format of ``p`` to data in 1-d array ``buf``.