graph: Factor out common code in edge addition
diff --git a/src/graph.rs b/src/graph.rs
index f62df09..2d68af5 100644
--- a/src/graph.rs
+++ b/src/graph.rs
@@ -520,29 +520,7 @@
/// to avoid this, use [`.update_edge(a, b, weight)`](#method.update_edge) instead.
pub fn add_edge(&mut self, a: NodeIndex<Ix>, b: NodeIndex<Ix>, weight: E) -> EdgeIndex<Ix>
{
- let edge_idx = EdgeIndex::new(self.edges.len());
- assert!(Ix::max().index() == !0 || EdgeIndex::end() != edge_idx);
- let mut edge = Edge {
- weight: weight,
- node: [a, b],
- next: [EdgeIndex::end(); 2],
- };
- match index_twice(&mut self.nodes, a.index(), b.index()) {
- Pair::None => panic!("Graph::add_edge: node indices out of bounds"),
- Pair::One(an) => {
- edge.next = an.next;
- an.next[0] = edge_idx;
- an.next[1] = edge_idx;
- }
- Pair::Both(an, bn) => {
- // a and b are different indices
- edge.next = [an.next[0], bn.next[1]];
- an.next[0] = edge_idx;
- bn.next[1] = edge_idx;
- }
- }
- self.edges.push(edge);
- edge_idx
+ VacantEdgeEntry::new(self, a, b).add_edge(weight).0
}
/// Add or update an edge from `a` to `b`.
@@ -845,22 +823,7 @@
-> EdgeEntry<N, E, Ix>
{
match self.find_edge(a, b) {
- None => {
- let edge_idx = edge_index::<Ix>(self.edges.len());
- assert!(Ix::max().index() == !0 || EdgeIndex::end() != edge_idx);
- let (an, bn) = match index_twice(&mut self.nodes, a.index(), b.index()) {
- Pair::None => panic!("Graph::edge_entry: node indices out of bounds"),
- Pair::One(an) => (an, None),
- Pair::Both(an, bn) => (an, Some(bn))
- };
- EdgeEntry::Vacant(VacantEdgeEntry {
- a: a,
- b: b,
- an: an,
- bn: bn,
- edges: &mut self.edges,
- })
- }
+ None => EdgeEntry::Vacant(VacantEdgeEntry::new(self, a, b)),
Some(i) => {
EdgeEntry::Occupied(OccupiedEdgeEntry {
index: i,
@@ -1412,6 +1375,27 @@
impl<'a, N, E, Ix> VacantEdgeEntry<'a, N, E, Ix>
where Ix: IndexType,
{
+ fn new<Ty>(graph: &'a mut Graph<N, E, Ty, Ix>,
+ a: NodeIndex<Ix>, b: NodeIndex<Ix>) -> Self
+ where Ty: EdgeType
+ {
+ let edge_idx = edge_index::<Ix>(graph.edges.len());
+ assert!(Ix::max().index() == !0 || EdgeIndex::end() != edge_idx);
+ let (an, bn) = match index_twice(&mut graph.nodes, a.index(), b.index()) {
+ Pair::None => panic!("Graph: node index {} or {} out of bounds",
+ a.index(), b.index()),
+ Pair::One(an) => (an, None),
+ Pair::Both(an, bn) => (an, Some(bn))
+ };
+ VacantEdgeEntry {
+ a: a,
+ b: b,
+ an: an,
+ bn: bn,
+ edges: &mut graph.edges,
+ }
+ }
+
pub fn index(&self) -> EdgeIndex<Ix> {
edge_index(self.edges.len())
}
