mapped_struct.py 文件源码

def __get__(self, obj, klass):
        if obj is None:
            return self
        elif obj.none_bitmap & self.mask:
            return None
        if cython.compiled:
            pybuf = cython.address(obj.pybuf)
            buflen = pybuf.len
            assert (obj.offs + self.offs + cython.sizeof(cython.longlong)) <= buflen
            offs = obj.offs + cython.cast(cython.p_longlong,
                cython.cast(cython.p_uchar, pybuf.buf) + obj.offs + self.offs)[0]
            if obj.idmap is not None:
                poffs = offs # python version of offs
                rv = obj.idmap.get(poffs, poffs) # idmap cannot possibly hold "poffs" for that offset
                if rv is not poffs:
                    return rv
            assert offs + cython.sizeof(cython.ushort) <= buflen
        else:
            poffs = offs = obj.offs + struct.unpack_from('q', obj.buf, obj.offs + self.offs)[0]
        rv = self.typ.unpack_from(obj.buf, offs)
        if obj.idmap is not None:
            obj.idmap[poffs] = rv
        return rv