}

	n = len(b0) - len(b)
	switch {
	case err == ErrWriteTooLong:
		return n, errMissData // Not possible; implies bug in validation logic
	case err != nil:
		return n, err
	case sw.logicalRemaining() == 0 && sw.physicalRemaining() > 0:
		return n, errUnrefData // Not possible; implies bug in validation logic
	case overwrite:
		return n, ErrWriteTooLong
	default:
		return n, nil
	}
}

		header: h,
		zipw:   w.cw,
	}
	w.last = fw
	return fw, nil
}

// Copy copies the file f (obtained from a [Reader]) into w. It copies the raw
// form directly bypassing decompression, compression, and validation.
func (w *Writer) Copy(f *File) error {
	r, err := f.OpenRaw()
	if err != nil {
		return err
	}
	// Copy the FileHeader so w doesn't store a pointer to the data
	// of f's entire archive. See #65499.