public static String u2or4(int v) {
    if (v == (char) v) {
      return u2(v);
    } else {
      return u4(v);
    }
  }
Formats an {@code int} as either a 2-byte unsigned hex value (if the value is small enough) or
a 4-byte unsigned hex value (if not).

@param v value to format
@return {@code non-null;} formatted form
android/android_framework/dex-maker/src/main/java/com/android/dx/util/Hex.java