func (r *Regexp) re() *regexp.Regexp {
	r.once.Do(r.build)
	return r.rx
}

func (r *Regexp) build() {
	r.rx = regexp.MustCompile(r.str)
	r.str = ""
}

func (r *Regexp) FindSubmatch(s []byte) [][]byte {
	return r.re().FindSubmatch(s)
}

func (r *Regexp) FindStringSubmatch(s string) []string {
	return r.re().FindStringSubmatch(s)
}

func (r *Regexp) FindStringSubmatchIndex(s string) []int {

func (r *Regexp) re() *regexp.Regexp {
	r.once.Do(r.build)
	return r.rx
}

func (r *Regexp) build() {
	r.rx = regexp.MustCompile(r.str)
	r.str = ""
}

func (r *Regexp) FindSubmatch(s []byte) [][]byte {
	return r.re().FindSubmatch(s)
}

func (r *Regexp) FindStringSubmatch(s string) []string {
	return r.re().FindStringSubmatch(s)
}

func (r *Regexp) FindStringSubmatchIndex(s string) []int {

	"testing"
)

func getFeatureList() ([]string, error) {
	cpuinfo, err := os.ReadFile("/proc/cpuinfo")
	if err != nil {
		return nil, err
	}
	r := regexp.MustCompile("features\\s*:\\s*(.*)")
	b := r.FindSubmatch(cpuinfo)
	if len(b) < 2 {
		return nil, errors.New("no feature list in /proc/cpuinfo")
	}
	return regexp.MustCompile("\\s+").Split(string(b[1]), -1), nil
}

func TestS390XAgainstCPUInfo(t *testing.T) {

		return b
	}
	b, err := os.ReadFile(filepath.Join(testenv.IstioSrc, "Makefile.core.mk"))
	if err != nil {
		log.Fatalf("failed to read file: %v", err)
		return "unknown"
	}
	match := baseVersionRegexp.FindSubmatch(b)
	if len(match) < 2 {
		log.Fatalf("failed to find match")
		return "unknown"
	}
	return string(match[1])
}

var istioVersionRegexp = regexp.MustCompile(`VERSION \?= (.*)`)

		data, err := ioutil.ReadFile(filepath.Join(dir, f.Name()))
		if err != nil {
			panic(err)
		}
		var containsVal bool
		for _, line := range bytes.Split(data, []byte("\n")) {
			m := valRe.FindSubmatch(line)
			if m == nil {
				continue
			}
			containsVal = true
			s, err := strconv.Unquote(string(m[1]))
			if err != nil {
				panic(err)
			}
			if len(s) != wantLen {

)

func checkFile(name, expected string) (bool, error) {
	data, err := os.ReadFile(name)
	if err != nil {
		return false, err
	}
	for _, line := range bytes.Split(data, []byte("\n")) {
		m := valRe.FindSubmatch(line)
		if m == nil {
			continue
		}
		fmt.Println(strconv.Unquote(string(m[1])))
		if s, err := strconv.Unquote(string(m[1])); err != nil {
			return false, err
		} else if s == expected {
			return true, nil

	if err != nil {
		t.Skipf("failed to get swig version:%s\n%s", err, string(out))
	}

	re := regexp.MustCompile(`[vV]ersion +(\d+)([.]\d+)?([.]\d+)?`)
	matches := re.FindSubmatch(out)
	if matches == nil {
		// Can't find version number; hope for the best.
		t.Logf("failed to find swig version, continuing")
		return
	}

	var parseError error
	atoi := func(s string) int {

					// gcc, but does not support gcc's "-v" flag?!
					return err
				}
				gccRE := regexp.MustCompile(`gcc version (\d+)\.(\d+)`)
				match = gccRE.FindSubmatch(out)
			} else {
				clangRE := regexp.MustCompile(`clang version (\d+)\.(\d+)`)
				if match = clangRE.FindSubmatch(out); len(match) > 0 {
					compiler.name = "clang"
				}
			}

			if len(match) < 3 {
				return nil // "unknown"
			}

	s := []byte("acbb" + wantSubs + "dd")
	b.StartTimer()
	b.ReportAllocs()
	for i := 0; i < b.N; i++ {
		subs := re.FindSubmatch(s)
		if string(subs[0]) != wantSubs {
			b.Fatalf("FindSubmatch(%q)[0] = %q; want %q", s, subs[0], wantSubs)
		}
		if string(subs[1]) != "aab" {
			b.Fatalf("FindSubmatch(%q)[1] = %q; want %q", s, subs[1], "aab")
		}
	}
}

func BenchmarkFindStringSubmatch(b *testing.B) {

					// gcc, but does not support gcc's "-v" flag?!
					return err
				}
				gccRE := regexp.MustCompile(`(\d+)\.(\d+)`)
				match = gccRE.FindSubmatch(out)
			} else {
				clangRE := regexp.MustCompile(`clang version (\d+)\.(\d+)`)
				if match = clangRE.FindSubmatch(out); len(match) > 0 {
					compiler.name = "clang"
				}
			}

			if len(match) < 3 {
				return nil // "unknown"
			}