def make_crc_adapter()

in oss2/utils.py [0:0]

• 14 lines of code
• 7 McCabe index (conditional complexity)

def make_crc_adapter(data, init_crc=0, discard=0):
    """返回一个适配器，从而在读取 `data` ，即调用read或者对其进行迭代的时候，能够计算CRC。

    :param discard:
    :return:
    :param data: 可以是bytes、file object或iterable
    :param init_crc: 初始CRC值，可选

    :return: 能够调用计算CRC函数的适配器
    """
    data = to_bytes(data)

    # bytes or file object
    if _has_data_size_attr(data):
        if discard:
            raise ClientError('Bytes of file object adapter does not support discard bytes')
        return _BytesAndFileAdapter(data, size=_get_data_size(data), crc_callback=Crc64(init_crc))
    # file-like object
    elif hasattr(data, 'read'):
        return _FileLikeAdapter(data, crc_callback=Crc64(init_crc), discard=discard)
    # iterator
    elif hasattr(data, '__iter__'):
        if discard:
            raise ClientError('Iterator adapter does not support discard bytes')
        return _IterableAdapter(data, crc_callback=Crc64(init_crc))
    else:
        raise ClientError('{0} is not a file object, nor an iterator'.format(data.__class__.__name__))