docs: private static boolean[] createSafeOctets(String safeChars) {
      int maxChar = -1;
      char[] safeCharArray = safeChars.toCharArray();
      for (char c : safeCharArray) {
        maxChar = Math.max(c, maxChar);
      }
      boolean[] octets = new boolean[maxChar + 1];
      for (char c : safeCharArray) {
        octets[c] = true;
      }
      return octets;
    }