code: public long getLastPrimaryForGroup(int script) {
          int index = getScriptIndex(script);
          if(index == 0) {
              return 0;
          }
          long limit = scriptStarts[index + 1];
          return (limit << 16) - 1;
      }
docs: Returns the last primary for the script's reordering group.
  @return the last primary of the group
  (not an actual root collator primary weight),
  or 0 if the script is unknown