// ReadSlice returns err != nil if and only if line does not end in delim.
func (b *Reader) ReadSlice(delim byte) (line []byte, err error) {
	s := 0 // search start index
	for {
		// Search buffer.
		if i := bytes.IndexByte(b.buf[b.r+s:b.w], delim); i >= 0 {
			i += s
			line = b.buf[b.r : b.r+i+1]
			b.r += i + 1
			break
		}

		// Pending error?
		if b.err != nil {
			line = b.buf[b.r:b.w]
			b.r = b.w

			}
		}
	}
	if start.Name.Local == "" && finfo != nil {
		start.Name.Space, start.Name.Local = finfo.xmlns, finfo.name
	}
	if start.Name.Local == "" {
		name := typ.Name()
		if i := strings.IndexByte(name, '['); i >= 0 {
			// Truncate generic instantiation name. See issue 48318.
			name = name[:i]
		}
		if name == "" {
			return &UnsupportedTypeError{typ}
		}
		start.Name.Local = name
	}

// fail.
func DecryptETag(key crypto.ObjectKey, object ObjectInfo) (string, error) {
	if n := strings.Count(object.ETag, "-"); n > 0 {
		if n != 1 {
			return "", errObjectTampered
		}
		i := strings.IndexByte(object.ETag, '-')
		if len(object.ETag[:i]) != 32 {
			return "", errObjectTampered
		}
		if _, err := hex.DecodeString(object.ETag[:32]); err != nil {
			return "", errObjectTampered
		}

	// proceed if f doesn't underflow to 0 or overflow to inf.
	if x, _ := f.Float64(); f.Sign() == 0 == (x == 0) && !math.IsInf(x, 0) {
		s := fmt.Sprintf("%.6g", x)
		if !f.IsInt() && strings.IndexByte(s, '.') < 0 {
			// f is not an integer, but its string representation
			// doesn't reflect that. Use more digits. See issue 56220.
			s = fmt.Sprintf("%g", x)
		}
		return s
	}

		// (Content ID in the new content-based build IDs.)
		const marker = `build id "`
		i := bytes.Index(data, []byte(marker))
		if i < 0 {
			t.Fatal("cannot find build id in archive")
		}
		j := bytes.IndexByte(data[i+len(marker):], '"')
		if j < 0 {
			t.Fatal("cannot find build id in archive")
		}
		i += len(marker) + j - 1
		if data[i] == 'a' {
			data[i] = 'b'
		} else {
			data[i] = 'a'
		}

// with the replacement text repl.
// Inside repl, $ signs are interpreted as in [Regexp.Expand].
func (re *Regexp) ReplaceAll(src, repl []byte) []byte {
	n := 2
	if bytes.IndexByte(repl, '$') >= 0 {
		n = 2 * (re.numSubexp + 1)
	}
	srepl := ""
	b := re.replaceAll(src, "", n, func(dst []byte, match []int) []byte {
		if len(srepl) != len(repl) {
			srepl = string(repl)
		}

		// of uinptrs this function consumes. Store the argsize and discard
		// the %n suffix if any.
		m.argsize = -1
		extName := ldr.SymExtname(s)
		if i := strings.IndexByte(extName, '%'); i >= 0 {
			var err error
			m.argsize, err = strconv.Atoi(extName[i+1:])
			if err != nil {
				ctxt.Errorf(s, "failed to parse stdcall decoration: %v", err)
			}

		kv := env[n-1]

		// Reject NUL in environment variables to prevent security issues (#56284);
		// except on Plan 9, which uses NUL as os.PathListSeparator (#56544).
		if !nulOK && strings.IndexByte(kv, 0) != -1 {
			err = errors.New("exec: environment variable contains NUL")
			continue
		}

		i := strings.Index(kv, "=")
		if i == 0 {

			return ""
		}
		i += lenp + k + 1
		if c := sub[lenp+k]; c == '\'' || c == '"' {
			sep = c
			break
		}
	}
	if sep == 0 {
		return ""
	}
	j := strings.IndexByte(s[i:], sep)
	if j < 0 {
		return ""
	}
	return s[i : i+j]

}

// needed for re-marshaling tests
func (u unmarshalerText) MarshalText() ([]byte, error) {
	return []byte(u.A + ":" + u.B), nil
}

func (u *unmarshalerText) UnmarshalText(b []byte) error {
	pos := bytes.IndexByte(b, ':')
	if pos == -1 {
		return errors.New("missing separator")
	}
	u.A, u.B = string(b[:pos]), string(b[pos+1:])
	return nil
}

var _ encoding.TextUnmarshaler = (*unmarshalerText)(nil)