base.py 文件源码

def __len__(self):
        fmt = ''
        more_len = 0
        for field in self._field_names_:
            fmt_ = self._field_format_[field]
            if isinstance(fmt_, StructArray):
                fmt += fmt_.get_struct()
            elif isinstance(fmt_, type) and issubclass(fmt_, Struct):
                more_len = len(fmt)
            elif fmt_ != 'variable':
                fmt += fmt_
        hdr_len = struct.calcsize(fmt) + more_len
        if hasattr(self, 'data'):
            hdr_len += len(self.data)
        return hdr_len