utf-8 has an elegance that utf-16 lacks:

    utf-8 decode
      switch (std::countl_one(unit)) {
        case 0:
          /* one unit */
          break;
        case 2:
          /* two units */
          break;
        case 3:
          /* three units */
          break;
        case 4:
          /* four units */
          break;
        default:
          /* not code point boundary */
          break;
      }