public TermData subtract(TermData t1, TermData t2) {if (t2 == NO_OUTPUT) {return t1;}TermData ret;if (statsEqual(t1, t2) && bytesEqual(t1, t2)) {ret = NO_OUTPUT;} else {ret = new TermData(t1.bytes, t1.docFreq, t1.totalTermFreq);}return ret;}