code: public static final int codePointBefore(char[] text, int index) {
          char c2 = text[--index];
          if (isLowSurrogate(c2)) {
              if (index > 0) {
                  char c1 = text[--index];
                  if (isHighSurrogate(c1)) {
                      return toCodePoint(c1, c2);
                  }
              }
          }
          return c2;
      }
docs: Same as {@link Character#codePointBefore(char[], int)}.
  Returns the code point before index.
  This examines only the characters at index-1 and index-2.
  
  @param text the characters to check
  @param index the index after the last or only char forming the code point
  @return the code point before the index