}
			files = append(files, file{header: &f.FileHeader, content: content})
			if _, err := r.Open(f.Name); err != nil {
				continue
			}
		}

		// If we were unable to read anything out of the archive don't
		// bother trying to roundtrip it.
		if len(files) == 0 {
			return
		}

		w := NewWriter(io.Discard)
		for _, f := range files {
			ww, err := w.CreateHeader(f.header)
			if err != nil {

			if _, err := io.Copy(buf, r); err != nil {
				continue
			}
			files = append(files, file{header: hdr, content: buf.Bytes()})
		}

		// If we were unable to read anything out of the archive don't
		// bother trying to roundtrip it.
		if len(files) == 0 {
			return
		}

		out := bytes.NewBuffer(nil)
		w := NewWriter(out)
		for _, f := range files {
			if err := w.WriteHeader(f.header); err != nil {