docs: protected char[] nextCJKSentence( int c ) throws IOException 
      {
          isb.clear();
          int ch;
          isb.append((char)c);
          
          //reset the CE check mask.
          ctrlMask &= ~ISegment.CHECK_CE_MASk;
          
          while ( (ch = readNext()) != -1 ) {
              if ( StringUtil.isWhitespace(ch) ) {
                  pushBack(ch);
                  break;
              }
              
              if ( ! StringUtil.isCJKChar(ch) ) {
                  pushBack(ch);
                  /*check Chinese English mixed word*/
                  if ( StringUtil.isEnLetter(ch) 
                          || StringUtil.isEnNumeric(ch) ) {
                      ctrlMask |= ISegment.CHECK_CE_MASk;
                  }
                  break;
              } 
              
              isb.append((char)ch);
          }
          
          return isb.toString().toCharArray();
      }