if err != ErrFormat {
		t.Errorf("zeroes: error=%v, want %v", err, ErrFormat)
	}

	// repeated directoryEndSignatures
	sig := make([]byte, 4)
	binary.LittleEndian.PutUint32(sig, directoryEndSignature)
	for i := 0; i < size-4; i += 4 {
		copy(b[i:i+4], sig)
	}
	_, err = NewReader(bytes.NewReader(b), size)
	if err != ErrFormat {
		t.Errorf("sigs: error=%v, want %v", err, ErrFormat)
	}

pkg syscall (netbsd-arm64-cgo), const IPV6_VERSION_MASK = 240
pkg syscall (netbsd-arm64-cgo), const IPV6_VERSION_MASK ideal-int
pkg syscall (netbsd-arm64-cgo), const ISIG = 128
pkg syscall (netbsd-arm64-cgo), const ISIG ideal-int
pkg syscall (netbsd-arm64-cgo), const ISTRIP = 32
pkg syscall (netbsd-arm64-cgo), const ISTRIP ideal-int
pkg syscall (netbsd-arm64-cgo), const IXANY = 2048

		UncompressedSize64: 5678,
	}); err != nil {
		t.Fatal(err)
	}
	if err := w.Close(); err != nil {
		t.Fatal(err)
	}
	b := buf.Bytes()

	var sig [4]byte
	binary.LittleEndian.PutUint32(sig[:], uint32(fileHeaderSignature))

	idx := bytes.Index(b, sig[:])
	if idx == -1 {
		t.Fatal("file header not found")
	}
	b = b[idx:]

pkg syscall (windows-386), const DNS_TYPE_SIG ideal-int
pkg syscall (windows-386), const DNS_TYPE_SINK ideal-int
pkg syscall (windows-386), const DNS_TYPE_SOA ideal-int
pkg syscall (windows-386), const DNS_TYPE_SRV ideal-int
pkg syscall (windows-386), const DNS_TYPE_TEXT ideal-int
pkg syscall (windows-386), const DNS_TYPE_TKEY ideal-int
pkg syscall (windows-386), const DNS_TYPE_TSIG ideal-int

pkg syscall (darwin-arm64), const IP_TTL = 4
pkg syscall (darwin-arm64), const IP_UNBLOCK_SOURCE = 73
pkg syscall (darwin-arm64), const IP_UNBLOCK_SOURCE ideal-int
pkg syscall (darwin-arm64), const ISIG = 128
pkg syscall (darwin-arm64), const ISIG ideal-int
pkg syscall (darwin-arm64), const ISTRIP = 32
pkg syscall (darwin-arm64), const ISTRIP ideal-int
pkg syscall (darwin-arm64), const IUTF8 = 16384

pkg syscall (freebsd-arm64), const IPV6_VERSION_MASK = 240
pkg syscall (freebsd-arm64), const IPV6_VERSION_MASK ideal-int
pkg syscall (freebsd-arm64), const ISIG = 128
pkg syscall (freebsd-arm64), const ISIG ideal-int
pkg syscall (freebsd-arm64), const ISTRIP = 32
pkg syscall (freebsd-arm64), const ISTRIP ideal-int
pkg syscall (freebsd-arm64), const IXANY = 2048

		return false
	}

	d = make([]byte, directory64EndLen)
	if _, err := zip.ReadAt(d, dirOff); err != nil {
		t.Fatalf("ReadAt(off=%d): %v", dirOff, err)
	}

	b := readBuf(d)
	if sig := b.uint32(); sig != directory64EndSignature {
		return false
	}

	size := b.uint64()
	if size != directory64EndLen-12 {
		t.Errorf("expected length of %d, got %d", directory64EndLen-12, size)
	}
	return true
}

pkg syscall (darwin-386), const IP_TRAFFIC_MGT_BACKGROUND = 65
pkg syscall (darwin-386), const IP_TTL = 4
pkg syscall (darwin-386), const IP_UNBLOCK_SOURCE = 73
pkg syscall (darwin-386), const ISIG = 128
pkg syscall (darwin-386), const ISIG ideal-int
pkg syscall (darwin-386), const ISTRIP = 32
pkg syscall (darwin-386), const ISTRIP ideal-int
pkg syscall (darwin-386), const IUTF8 = 16384
pkg syscall (darwin-386), const IUTF8 ideal-int

pkg syscall (freebsd-386-cgo), const IP_RSVP_VIF_ON ideal-int
pkg syscall (freebsd-386-cgo), const IP_SENDSRCADDR ideal-int
pkg syscall (freebsd-386-cgo), const IP_UNBLOCK_SOURCE ideal-int
pkg syscall (freebsd-386-cgo), const ISIG ideal-int
pkg syscall (freebsd-386-cgo), const ISTRIP ideal-int
pkg syscall (freebsd-386-cgo), const IXANY ideal-int
pkg syscall (freebsd-386-cgo), const IXOFF ideal-int
pkg syscall (freebsd-386-cgo), const IXON ideal-int

func (f *File) findBodyOffset() (int64, error) {
	var buf [fileHeaderLen]byte
	if _, err := f.zipr.ReadAt(buf[:], f.headerOffset); err != nil {
		return 0, err
	}
	b := readBuf(buf[:])
	if sig := b.uint32(); sig != fileHeaderSignature {
		return 0, ErrFormat
	}
	b = b[22:] // skip over most of the header
	filenameLen := int(b.uint16())
	extraLen := int(b.uint16())