+ protected boolean pruneColumnList(final List<int[]> shifts)
+ {
+ int s = 0, t = shifts.size();
+ int[] sr = shifts.get(s++);
+ boolean pruned = false;
+ int i = 0, j = order.size();
+ while (i < j && s <= t)
+ {
+ int c = order.get(i++).intValue();
+ if (sr[0] <= c)
+ {
+ if (sr[1] + sr[0] >= c)
+ { // sr[1] -ve means inseriton.
+ order.remove(--i);
+ selected.clear(c);
+ j--;
+ }
+ else
+ {
+ if (s < t)
+ {
+ sr = shifts.get(s);
+ }
+ s++;
+ }
+ }
+ }
+ return pruned;
+ }
+
+ /**
+ * shift every selected column at or above start by change
+ *
+ * @param start
+ * - leftmost column to be shifted
+ * @param change
+ * - delta for shift
+ */
+ void compensateForEdits(int start, int change)
+ {
+ BitSet mask = new BitSet();
+ for (int i = 0; i < order.size(); i++)
+ {
+ int temp = order.get(i);
+
+ if (temp >= start)
+ {
+ // clear shifted bits and update List of selected columns
+ selected.clear(temp);
+ mask.set(temp - change);
+ order.set(i, Integer.valueOf(temp - change));
+ }
+ }
+ // lastly update the bitfield all at once
+ selected.or(mask);
+ }
+
+ boolean isSelected(int column)
+ {
+ return selected.get(column);
+ }
+
+ int getMaxColumn()
+ {
+ return selected.length() - 1;
+ }
+
+ int getMinColumn()
+ {
+ return selected.get(0) ? 0 : selected.nextSetBit(0);
+ }
+
+ /**
+ * @return a series of selection intervals along the range
+ */
+ List<int[]> getRanges()
+ {
+ List<int[]> rlist = new ArrayList<>();
+ if (selected.isEmpty())
+ {
+ return rlist;
+ }
+ int next = selected.nextSetBit(0), clear = -1;
+ while (next != -1)
+ {
+ clear = selected.nextClearBit(next);
+ rlist.add(new int[] { next, clear - 1 });
+ next = selected.nextSetBit(clear);
+ }
+ return rlist;
+ }
+
+ @Override
+ public int hashCode()
+ {
+ // TODO Auto-generated method stub
+ return selected.hashCode();
+ }
+
+ @Override
+ public boolean equals(Object obj)
+ {
+ if (obj instanceof IntList)
+ {
+ return ((IntList) obj).selected.equals(selected);
+ }
+ return false;
+ }
+ }
+
+ private IntList selection = new IntList();