void (int index1, int index2, int end1, int end2) { if (index1 == end1 && index2 == end2) return; assert myIndex1 <= index1; assert myIndex2 <= index2; assert index1 <= end1; assert index2 <= end2; if (myIndex1 != index1 || myIndex2 != index2) { addChange(myIndex1, myIndex2, index1, index2); } myIndex1 = end1; myIndex2 = end2; }