r, w := rune(0), 0
	for i := 0; i < len(s); i += w {
		// Cannot use 'for range s' because we need to preserve the width
		// of the runes in the input. If we see a decoding error, the input
		// width will not be utf8.Runelen(r) and we will overrun the buffer.
		r, w = utf8.DecodeRuneInString(s[i:])
		if int(r) < len(replacementTable) {
			if repl := replacementTable[r]; len(repl) != 0 {
				if written == 0 {
					b.Grow(len(s))
				}

	}
	r, size = DecodeRuneInString(s[start:end])
	if start+size != end {
		return RuneError, 1
	}
	return r, size
}

// RuneLen returns the number of bytes in the UTF-8 encoding of the rune.
// It returns -1 if the rune is not a valid value to encode in UTF-8.
func RuneLen(r rune) int {
	switch {
	case r < 0:
		return -1
	case r <= rune1Max:
		return 1
	case r <= rune2Max:
		return 2

	buf := bytes.NewBuffer(nil)
	for _, r := range m {
		// Ignore non-printable characters
		if !unicode.IsPrint(r) {
			continue
		}
		// Only append if we have room for it
		if buf.Len()+utf8.RuneLen(r) > validation.FieldManagerMaxLength {
			break
		}
		buf.WriteRune(r)
	}
	return buf.String()

pkg syscall (windows-386), const WSAENOPROTOOPT Errno #62254
pkg syscall (windows-amd64), const WSAENOPROTOOPT = 10042 #62254
pkg syscall (windows-amd64), const WSAENOPROTOOPT Errno #62254
pkg unicode/utf16, func RuneLen(int32) int #44940
pkg unique, func Make[$0 comparable]($0) Handle[$0] #62483
pkg unique, method (Handle[$0]) Value() $0 #62483

			"byLiteral.Swap",
			"(*dictDecoder).tryWriteCopy",
		},
		"encoding/base64": {
			"assemble32",
			"assemble64",
		},
		"unicode/utf8": {
			"FullRune",
			"FullRuneInString",
			"RuneLen",
			"AppendRune",
			"ValidRune",
		},
		"unicode/utf16": {
			"Decode",
		},
		"reflect": {
			"Value.Bool",
			"Value.Bytes",
			"Value.CanAddr",
			"Value.CanComplex",

	i := len(buf)

	// For %#U we want to add a space and a quoted character at the end of the buffer.
	if f.sharp && u <= utf8.MaxRune && strconv.IsPrint(rune(u)) {
		i--
		buf[i] = '\''
		i -= utf8.RuneLen(rune(u))
		utf8.EncodeRune(buf[i:], rune(u))
		i--
		buf[i] = '\''
		i--
		buf[i] = ' '
	}
	// Format the Unicode code point u as a hexadecimal number.
	for u >= 16 {
		i--

		}
		break
	}
	if errRead == io.EOF {
		return nil, errRead
	}

	// Parse each field in the record.
	var err error
	const quoteLen = len(`"`)
	commaLen := utf8.RuneLen(r.Comma)
	recLine := r.numLine // Starting line for record
	r.recordBuffer = r.recordBuffer[:0]
	r.fieldIndexes = r.fieldIndexes[:0]
	r.fieldPositions = r.fieldPositions[:0]
	pos := position{line: r.numLine, col: 1}

		buf.Reset()
		for i := 0; i < n; i++ {
			buf.WriteByte('x')
		}
	}
}

func BenchmarkWriteRune(b *testing.B) {
	const n = 4 << 10
	const r = '☺'
	b.SetBytes(int64(n * utf8.RuneLen(r)))
	buf := NewBuffer(make([]byte, n*utf8.UTFMax))
	for i := 0; i < b.N; i++ {
		buf.Reset()
		for i := 0; i < n; i++ {
			buf.WriteRune(r)
		}
	}
}

// From Issue 5154.

	}(p.scanner.Whitespace)
	p.scanner.Whitespace = 0

	got := 0
	for got < want {
		r := p.scanner.Next()
		if r == scanner.EOF {
			p.error("unexpected EOF")
		}
		got += utf8.RuneLen(r)
	}
}

// Types = "types" maxp1 exportedp1 (offset length)* .
func (p *parser) parseTypes(pkg *types.Package) {
	maxp1 := p.parseInt()
	exportedp1 := p.parseInt()

			continue
		}

		var width int
		if c == utf8.RuneError {
			c, width = utf8.DecodeRuneInString(s[i:])
			if width != 1 && r == c {
				continue
			}
		} else {
			width = utf8.RuneLen(c)
		}

		b.Grow(len(s) + utf8.UTFMax)
		b.WriteString(s[:i])
		if r >= 0 {
			b.WriteRune(r)
		}

		s = s[i+width:]
		break
	}

	// Fast path for unchanged input