}
	for len(p) > 0 {
		n := copy(ss.buf[ss.start:], p)
		p = p[n:]
		ss.start += n
		if ss.start == ss.keep {
			ss.start = 0
		}
	}
	return
}

// generatesZip64 reports whether f wrote a zip64 file.
// f is also responsible for closing w.
func generatesZip64(t *testing.T, f func(w *Writer)) bool {
	ss := &suffixSaver{keep: 10 << 20}
	w := NewWriter(ss)
	f(w)
	return suffixIsZip64(t, ss)
}