r       *Replacer
		in, out string
	}
	var testCases []testCase

	// str converts 0xff to "\xff". This isn't just string(b) since that converts to UTF-8.
	str := func(b byte) string {
		return string([]byte{b})
	}
	var s []string

	// inc maps "\x00"->"\x01", ..., "a"->"b", "b"->"c", ..., "\xff"->"\x00".
	s = nil
	for i := 0; i < 256; i++ {
		s = append(s, str(byte(i)), str(byte(i+1)))
	}

	{"1 2", " ", 3, []string{"1", "2"}},
	{"123", "", 2, []string{"1", "23"}},
	{"123", "", 17, []string{"1", "2", "3"}},
	{"bT", "T", math.MaxInt / 4, []string{"b", ""}},
	{"\xff-\xff", "", -1, []string{"\xff", "-", "\xff"}},
	{"\xff-\xff", "-", -1, []string{"\xff", "\xff"}},
}

func TestSplit(t *testing.T) {
	for _, tt := range splittests {
		a := SplitN([]byte(tt.s), []byte(tt.sep), tt.n)

  if [[ ! -f ${tmp_png_file} ]] ; then
    echo "pdftoppm does not work."
    exit 1
  fi
  convert -thumbnail ${image_size} ${tmp_png_file} "${output_file}"
  rm -f ${tmp_png_prefix}*png
elif [[ x"${cmd_type}" = "xpdf" ]] ; then
  check_command convert
  check_command pdftoppm
  target_file=$(echo "$url" | sed -e "s#^file:/*#/#g")
  tmp_png_prefix=/tmp/thumbnail.png.$$
  pdftoppm -png -singlefile "${target_file}" ${tmp_png_prefix}

type unQuoteTest struct {
	in  string
	out string
}

var unquotetests = []unQuoteTest{
	{`""`, ""},
	{`"a"`, "a"},
	{`"abc"`, "abc"},
	{`"☺"`, "☺"},
	{`"hello world"`, "hello world"},
	{`"\xFF"`, "\xFF"},
	{`"\377"`, "\377"},
	{`"\u1234"`, "\u1234"},
	{`"\U00010111"`, "\U00010111"},
	{`"\U0001011111"`, "\U0001011111"},
	{`"\a\b\f\n\r\t\v\\\""`, "\a\b\f\n\r\t\v\\\""},
	{`"'"`, "'"},

	{`'a'`, "a"},

				bc = int(b[i])
			}
			if ac != bc {
				print("\ta[", i, "] = ", ac, "; b[", i, "] =", bc, "\n")
			}
		}
		panic("string_lit")
	}
}

const (
	gx1    = "aä本☺"
	gx2    = "aä\xFF\xFF本☺"
	gx2fix = "aä\uFFFD\uFFFD本☺"
)

var (
	gr1 = []rune(gx1)
	gr2 = []rune(gx2)
	gb1 = []byte(gx1)
	gb2 = []byte(gx2)
)

func main() {
	ecode = 0
	s :=
		"" +
			" " +
			"'`" +

			wantCT: "text/html; charset=utf-8",
		},
		{
			name:   "text",
			body:   strings.Repeat("gopher", 86),
			wantCT: "text/plain; charset=utf-8",
		},
		{
			name:   "jpg",
			body:   "\xFF\xD8\xFF" + strings.Repeat("B", 1024),
			wantCT: "image/jpeg",
		},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			var buf bytes.Buffer
			resp := response{

				buf = append(buf, lowerhex[r>>uint(s)&0xF])
			}
		}
	}
	return buf
}

// Quote returns a double-quoted Go string literal representing s. The
// returned string uses Go escape sequences (\t, \n, \xFF, \u0100) for
// control characters and non-printable characters as defined by
// [IsPrint].
func Quote(s string) string {
	return quoteWith(s, '"', false, false)
}

	`(a|b|))`,
	`(a|b`,
	`a|b)`,
	`(a|b))`,
	`[a-z`,
	`([a-z)`,
	`[a-z)`,
	`([a-z]))`,
	`x{1001}`,
	`x{9876543210}`,
	`x{2,1}`,
	`x{1,9876543210}`,
	"\xff", // Invalid UTF-8
	"[\xff]",
	"[\\\xff]",
	"\\\xff",
	`(?P<name>a`,
	`(?P<name>`,
	`(?P<name`,
	`(?P<x y>a)`,
	`(?P<>a)`,
	`(?<name>a`,
	`(?<name>`,
	`(?<name`,
	`(?<x y>a)`,
	`(?<>a)`,
	`[a-Z]`,

	*/
	const (
		ihdr = "\x00\x00\x00\x0dIHDR\x00\x00\x00\x01\x00\x00\x00\x01\x08\x03\x00\x00\x00\x28\xcb\x34\xbb"
		plte = "\x00\x00\x00\x03PLTE\xff\x00\x00\x19\xe2\x09\x37"
		trns = "\x00\x00\x00\x01tRNS\x7f\x80\x5c\xb4\xcb"
		idat = "\x00\x00\x00\x0eIDAT\x78\x9c\x62\x62\x00\x04\x00\x00\xff\xff\x00\x06\x00\x03\xfa\xd0\x59\xae"
		iend = "\x00\x00\x00\x00IEND\xae\x42\x60\x82"
	)
	for i := 0; i < 4; i++ {
		var b []byte

	// identityTransformer has to return an error if the data is encoded using another transformer.
	// JSON data starts with '{'. Protobuf data has a prefix 'k8s[\x00-\xFF]'.
	// Prefix 'k8s:enc:' is reserved for encrypted data on disk.
	if bytes.HasPrefix(data, encryptedPrefix) {
		return nil, false, errEncryptedData
	}
	return data, false, nil
}