final int nbottom = rowOffset > 0 ? Math.min(maxRow, bottom) : bottom;
if (nleft > nright || ntop > nbottom) { //offset out of range
continue;
}
final RefAddr refAddr = new RefAddr(ntop, nleft, nbottom, nright);
if (refMap.containsKey(refAddr)) { //same area there, next
continue;
}
final Ref newRef = (nleft == nright && ntop == nbottom) ?
new CellRefImpl(ntop, nleft, refSheet) :