Add len() for VertexMap and EdgeMap

src/maps.rs

@@ -13,6 +13,11 @@ impl<V: Copy, T: Clone> VertexMap<V, T> {
         }
     }
 
+    // Reads beyond len() are valid and return the default value.
+    pub fn len(&self) -> usize {
+        self.inner.len()
+    }
+
     pub fn sync<G: GraphTopology<Vertex = V>>(&mut self, graph: &G) {
         self.inner.resize(graph.vertex_capacity());
     }
@@ -43,6 +48,11 @@ impl<E: Copy, T: Clone> EdgeMap<E, T> {
         }
     }
 
+    // Reads beyond len() are valid and return the default value.
+    pub fn len(&self) -> usize {
+        self.inner.len()
+    }
+
     pub fn sync<G: GraphTopology<Edge = E>>(&mut self, graph: &G) {
         self.inner.resize(graph.edge_capacity());
     }
@@ -77,6 +87,10 @@ impl<E: Copy, T: Clone> EntityMap<E, T> {
         }
     }
 
+    pub fn len(&self) -> usize {
+        self.data.len()
+    }
+
     pub fn resize(&mut self, capacity: usize) {
         if capacity > self.data.len() {
             self.data.resize(capacity, self.default.clone());

src/testing/maps_testing.rs

@@ -48,16 +48,16 @@ macro_rules! vertex_map_tests {
             let mut graph = <$T>::new();
             graph.add_vertex();
             let mut map = graph.vertex_map(42);
-            let initial_len = map.inner.data.len();
+            let initial_len = map.len();
             while graph.vertex_capacity() <= initial_len {
                 graph.add_vertex();
             }
             assert!(
-                map.inner.data.len() < graph.vertex_capacity(),
+                map.len() < graph.vertex_capacity(),
                 "precondition: map is stale before sync"
             );
             map.sync(&graph);
-            assert_eq!(map.inner.data.len(), graph.vertex_capacity());
+            assert_eq!(map.len(), graph.vertex_capacity());
         }
 
         #[test]
@@ -99,7 +99,7 @@ macro_rules! vertex_map_deletion_tests {
             let capacity_before = graph.vertex_capacity();
             graph.delete_vertex(v2);
             map.sync(&graph);
-            assert_eq!(map.inner.data.len(), capacity_before);
+            assert_eq!(map.len(), capacity_before);
             assert_eq!(map[v1], 5);
         }
 
@@ -180,16 +180,16 @@ macro_rules! edge_map_tests {
             let v2 = graph.add_vertex();
             graph.add_edge(v1, v2);
             let mut map = graph.edge_map(42);
-            let initial_len = map.inner.data.len();
+            let initial_len = map.len();
             while graph.edge_capacity() <= initial_len {
                 graph.add_edge(v1, v2);
             }
             assert!(
-                map.inner.data.len() < graph.edge_capacity(),
+                map.len() < graph.edge_capacity(),
                 "precondition: map is stale before sync"
             );
             map.sync(&graph);
-            assert_eq!(map.inner.data.len(), graph.edge_capacity());
+            assert_eq!(map.len(), graph.edge_capacity());
         }
 
         #[test]
@@ -237,7 +237,7 @@ macro_rules! edge_map_deletion_tests {
             let capacity_before = graph.edge_capacity();
             graph.delete_edge(e2);
             map.sync(&graph);
-            assert_eq!(map.inner.data.len(), capacity_before);
+            assert_eq!(map.len(), capacity_before);
             assert_eq!(map[e1], 5);
         }