if in.bytes != nil {
		return append(buf, in.bytes[b:e]...)
	}
	for i := b; i < e; i++ {
		buf = append(buf, in.str[i])
	}
	return buf
}

func (in *input) copySlice(buf []byte, b, e int) int {
	if in.bytes == nil {
		return copy(buf, in.str[b:e])
	}
	return copy(buf, in.bytes[b:e])
}

func (in *input) charinfoNFC(p int) (uint16, int) {
	if in.bytes == nil {