code: private boolean zzRefill() throws java.io.IOException {
  
      /* first: make room (if you can) */
      if (zzStartRead > 0) {
        System.arraycopy(zzBuffer, zzStartRead,
                         zzBuffer, 0,
                         zzEndRead-zzStartRead);
  
        /* translate stored positions */
        zzEndRead-= zzStartRead;
        zzCurrentPos-= zzStartRead;
        zzMarkedPos-= zzStartRead;
        zzStartRead = 0;
      }
  
      /* is the buffer big enough? */
      if (zzCurrentPos >= zzBuffer.length) {
        /* if not: blow it up */
        char newBuffer[] = new char[zzCurrentPos*2];
        System.arraycopy(zzBuffer, 0, newBuffer, 0, zzBuffer.length);
        zzBuffer = newBuffer;
      }
  
      /* finally: fill the buffer with new input */
      int numRead = zzReader.read(zzBuffer, zzEndRead,
                                              zzBuffer.length-zzEndRead);
  
      if (numRead > 0) {
        zzEndRead+= numRead;
        return false;
      }
      // unlikely but not impossible: read 0 characters, but not at end of stream    
      if (numRead == 0) {
        int c = zzReader.read();
        if (c == -1) {
          return true;
        } else {
          zzBuffer[zzEndRead++] = (char) c;
          return false;
        }     
      }
  
  	// numRead < 0
      return true;
    }
docs: Refills the input buffer.
  
  @return      <code>false</code>, iff there was new input.
  
  @exception   java.io.IOException  if any I/O-Error occurs