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;
  }