static new TreeMap<Long, S> ipToCountry_data;

static S ipToCountry(S ip) {
  long ipNum = ipToInt(trim(ip));
  synchronized(ipToCountry_data) {
    ipToCountry_init();
    Long key = data.floorKey(ipNum);
    ret key == null ? null : data.get(key);
  }
}

static void ipToCountry_init() {
  synchronized(ipToCountry_data) {
    if (nempty(ipToCountry_data)) ret;
    
    for (S s : linesFromReader(utf8bufferedReader(lzmaInputStream(#1004343))))) {
      L<S> l = tok_splitAtComma_unquote(s);
      if (l(l) < 3) continue;
      long start = parseLong(first(l));
      long end = parseLong(second(l));
      S country = intern(l.get(4));
      ipToCountry_data.put(start, country);
    }
  }
}

Began life as a copy of #1008738