// but these seem to be the values agreed on by tools.
	s_IFMT   = 0xf000
	s_IFSOCK = 0xc000
	s_IFLNK  = 0xa000
	s_IFREG  = 0x8000
	s_IFBLK  = 0x6000
	s_IFDIR  = 0x4000
	s_IFCHR  = 0x2000
	s_IFIFO  = 0x1000
	s_ISUID  = 0x800
	s_ISGID  = 0x400
	s_ISVTX  = 0x200

	msdosDir      = 0x10
	msdosReadOnly = 0x01
)

// Mode returns the permission and mode bits for the [FileHeader].

	utf8Valid1, utf8Require1 := detectUTF8(fh.Name)
	utf8Valid2, utf8Require2 := detectUTF8(fh.Comment)
	switch {
	case fh.NonUTF8:
		fh.Flags &^= 0x800
	case (utf8Require1 || utf8Require2) && (utf8Valid1 && utf8Valid2):
		fh.Flags |= 0x800
	}

	fh.CreatorVersion = fh.CreatorVersion&0xff00 | zipVersion20 // preserve compatibility byte
	fh.ReaderVersion = zipVersion20

		// Some ZIP writers use UTF-8 encoding without setting the UTF-8 flag.
		// Since it is impossible to always distinguish valid UTF-8 from some
		// other encoding (e.g., GBK or Shift-JIS), we trust the flag.
		f.NonUTF8 = f.Flags&0x800 == 0
	}

	needUSize := f.UncompressedSize == ^uint32(0)
	needCSize := f.CompressedSize == ^uint32(0)
	needHeaderOffset := f.headerOffset == int64(^uint32(0))

	// Best effort to find what we need.

	data := []byte{
		0x50, 0x4b, 0x03, 0x04, 0x14, 0x00, 0x08, 0x00,
		0x00, 0x00, 0x6b, 0xb4, 0xba, 0x46, 0x00, 0x00,
		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
		0x00, 0x00, 0x03, 0x00, 0x18, 0x00, 0xca, 0x64,
		0x55, 0x75, 0x78, 0x0b, 0x00, 0x50, 0x4b, 0x05,
		0x06, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x01,
		0x00, 0x49, 0x00, 0x00, 0x00, 0x44, 0x00, 0x00,
		0x00, 0x31, 0x31, 0x31, 0x32, 0x32, 0x32, 0x0a,

			name:    "hi, こんにちわ",
			comment: "in the world",
			flags:   0x808,
		},
		{
			name:    "hi, こんにちわ",
			comment: "in the world",
			nonUTF8: true,
			flags:   0x8,
		},
		{
			name:    "hi, hello",
			comment: "in the 世界",
			flags:   0x808,
		},
		{
			name:    "hi, こんにちわ",
			comment: "in the 世界",
			flags:   0x808,
		},
		{
			name:    "the replacement rune is �",

	MOVW	R1, 0x1002ffc(R2)	// MOVW		R1, 16789500(R2)	// 5bfc7f9161ff3fb9
	MOVD	R1, 0x8008(R2)		// MOVD		R1, 32776(R2)		// 5b204091610700f9
	MOVD	R1, 0x1006ff8(R2)	// MOVD		R1, 16805880(R2)	// 5bfc7f9161ff3ff9
	FMOVS	F1, 0x4004(R2)		// FMOVS	F1, 16388(R2)		// 5b104091610700bd
	FMOVS	F1, 0x1002ffc(R2)	// FMOVS	F1, 16789500(R2)	// 5bfc7f9161ff3fbd
	FMOVD	F1, 0x8008(R2)		// FMOVD	F1, 32776(R2)		// 5b204091610700fd

has initialized it.
The <code>GLOBL</code> directive must follow any corresponding <code>DATA</code> directives.
</p>

<p>
For example,
</p>

<pre>
DATA divtab&lt;&gt;+0x00(SB)/4, $0xf4f8fcff
DATA divtab&lt;&gt;+0x04(SB)/4, $0xe6eaedf0
...
DATA divtab&lt;&gt;+0x3c(SB)/4, $0x81828384
GLOBL divtab&lt;&gt;(SB), RODATA, $64

GLOBL runtime·tlsoffset(SB), NOPTR, $4
</pre>

<p>

		{"☻x\xe2\x98�", '�', len("☻x")},
		{"☻x\xe2\x98x", '�', len("☻x")},

		// Invalid rune values should never match.
		{"a☺b☻c☹d\xe2\x98�\xff�\xed\xa0\x80", -1, -1},
		{"a☺b☻c☹d\xe2\x98�\xff�\xed\xa0\x80", 0xD800, -1}, // Surrogate pair
		{"a☺b☻c☹d\xe2\x98�\xff�\xed\xa0\x80", utf8.MaxRune + 1, -1},
	}
	for _, tt := range tests {
		if got := IndexRune([]byte(tt.in), tt.rune); got != tt.want {

			prefix = p.parseString(ustar.prefix())

			// For Format detection, check if block is properly formatted since
			// the parser is more liberal than what USTAR actually permits.
			notASCII := func(r rune) bool { return r >= 0x80 }
			if bytes.IndexFunc(tr.blk[:], notASCII) >= 0 {
				hdr.Format = FormatUnknown // Non-ASCII characters in block.
			}
			nul := func(b []byte) bool { return int(b[len(b)-1]) == 0 }

		tw := NewWriter(new(bytes.Buffer))
		hdr := &Header{Name: "dir/", Typeflag: TypeDir}
		if err := tw.WriteHeader(hdr); err != nil {
			t.Fatalf("WriteHeader() = %v, want nil", err)
		}
		if _, err := tw.Write([]byte{0x00}); err != ErrWriteTooLong {
			t.Fatalf("Write() = %v, want %v", err, ErrWriteTooLong)
		}
	})

	t.Run("NegativeSize", func(t *testing.T) {
		tw := NewWriter(new(bytes.Buffer))