return nil, 0, 0, err
		}
		var decryptSkip int64
		var seqNum uint32

		off, length = int64(0), oi.Size
		decOff, decLength := int64(0), actualSize
		if rs != nil {
			off, length, err = rs.GetOffsetLength(actualSize)
			if err != nil {
				return nil, 0, 0, err
			}
			decrypt := func(b []byte) ([]byte, error) {
				return b, nil
			}
			if isEncrypted {
				decrypt = oi.compressionIndexDecrypt