code: public int nextCaseMapCP() {
          int c;
          if(cpLimit<limit) {
              cpStart=cpLimit;
              c=rep.char32At(cpLimit);
              cpLimit+=UTF16.getCharCount(c);
              return c;
          } else {
              return -1;
          }
      }
docs: Iterate forward through the string to fetch the next code point
  to be case-mapped, and set the context indexes for it.
  
  @return The next code point to be case-mapped, or <0 when the iteration is done.