Merge pull request #79 from krobelus/issue-77

RRB tree: use size table after pushing a sparse node to the left

src/nodes/rrb.rs

@@ -597,6 +597,13 @@ impl<A: Clone> Node<A> {
                 // more space in existing chunks. To keep the middle dense, we
                 // do not add it here.
                 if !chunk.is_empty() {
+                    if side == Left && chunk.len() < NODE_SIZE {
+                        if let Entry::Nodes(ref mut size, _) = self.children {
+                            if let Size::Size(value) = *size {
+                                *size = Size::table_from_size(level, value);
+                            }
+                        }
+                    }
                     self.push_size(side, chunk.len());
                     self.push_child_node(side, Ref::new(Node::from_chunk(0, chunk)));
                 }

src/vector/mod.rs

@@ -2616,6 +2616,20 @@ mod test {
         }
     }
 
+    #[test]
+    fn issue_77() {
+        let mut x = Vector::new();
+        for _ in 0..44 { x.push_back(0); }
+        for _ in 0..20 { x.insert(0, 0); }
+        x.insert(1, 0);
+        for _ in 0..441 { x.push_back(0); }
+        for _ in 0..58 { x.insert(0, 0); }
+        x.insert(514, 0);
+        for _ in 0..73 { x.push_back(0); }
+        for _ in 0..10 { x.insert(0, 0); }
+        x.insert(514, 0);
+    }
+
     proptest! {
         #[test]
         fn iter(ref vec in vec(i32::ANY, 0..1000)) {