fix: zero out offsets when consuming an iterator

Author: Dr-Emann

roaring/src/bitmap/store/interval_store.rs

@@ -731,6 +731,8 @@ impl<I: SliceIterator<Interval>> RunIter<I> {
                 if index == self.intervals.as_slice().len() {
                     // Consume the whole iterator
                     self.intervals.nth(index);
+                    self.forward_offset = 0;
+                    self.backward_offset = 0;
                     return;
                 }
                 if let Some(value) = index.checked_sub(1) {
@@ -779,6 +781,8 @@ impl<I: SliceIterator<Interval>> RunIter<I> {
                 if index == 0 {
                     // Consume the whole iterator
                     self.intervals.nth_back(self.intervals.as_slice().len());
+                    self.forward_offset = 0;
+                    self.backward_offset = 0;
                     return;
                 }
                 let backward_index = self.intervals.as_slice().len() - index;

roaring/tests/iter_advance_to.rs

@@ -247,6 +247,17 @@ fn advance_run_front_and_back_past_each_other() {
     assert_eq!(iter.next(), None);
 }
 
+#[test]
+fn advance_run_both_sides_past_each_other() {
+    let mut bitmap = RoaringBitmap::new();
+    bitmap.insert_range(0..0x1000);
+    let mut iter = bitmap.iter();
+    iter.advance_back_to(100);
+    iter.advance_to(0xFFFF);
+    assert_eq!(iter.len(), 0);
+    assert_eq!(iter.nth_back(0), None);
+}
+
 #[test]
 fn advance_run_with_nth() {
     let mut bitmap = RoaringBitmap::new();