fix: nth where n > u16::MAX is now correct

Author: Dr-Emann

roaring/src/bitmap/store/interval_store.rs

@@ -808,6 +808,13 @@ impl<I: SliceIterator<Interval>> Iterator for RunIter<I> {
     }
 
     fn nth(&mut self, n: usize) -> Option<Self::Item> {
+        if n > usize::from(u16::MAX) {
+            // Consume the whole iterator
+            self.intervals.nth(self.intervals.as_slice().len());
+            self.forward_offset = 0;
+            self.backward_offset = 0;
+            return None;
+        }
         if let Some(skip) = n.checked_sub(1) {
             let mut to_skip = skip as u64;
             loop {

roaring/tests/iter_advance_to.rs

@@ -246,3 +246,12 @@ fn advance_run_front_and_back_past_each_other() {
     iter.advance_to(300);
     assert_eq!(iter.next(), None);
 }
+
+#[test]
+fn advance_run_with_nth() {
+    let mut bitmap = RoaringBitmap::new();
+    bitmap.insert_range(36141..=224407);
+    let mut iter = bitmap.iter();
+    iter.advance_back_to(101779);
+    assert_eq!(iter.nth(100563), None);
+}