void write_ascii(std::basic_ostream<charT, traits>& os) const {
typename std::basic_ostream<charT, traits>::fmtflags save = os.flags();
size_t index_size = (size_t)1 << (num_indexed_chars*2);
for (size_t i = 0; i != index_size; ++i) {
for (index_type j = index[i]; j != index[i+1]; ++j) {
addr_type a = addr[j];
os << "[" << a << " " << string->substr(a, num_indexed_chars) << "]";
}
os << "\n";
}
os.setstate( save );
}
