code: public boolean stem(char[] wordBuffer, int offset, int wordLen) {
      reset();
      if (b.length < wordLen) {
        char[] new_b = new char[wordLen + EXTRA];
        b = new_b;
      }
      for (int j=0; j<wordLen; j++)
        b[j] = wordBuffer[offset+j];
      i = wordLen;
      return stem(0);
    }
docs: Stem a word contained in a portion of a char[] array.  Returns
  true if the stemming process resulted in a word different from
  the input.  You can retrieve the result with
  getResultLength()/getResultBuffer() or toString().