petgraph/visit/
reversed.rs

1
2use ::{
3    Direction,
4    Incoming,
5};
6
7use visit::{
8    GraphBase,
9    GraphRef,
10    IntoNodeIdentifiers,
11    IntoNodeReferences,
12    IntoNeighbors,
13    IntoNeighborsDirected,
14    IntoEdgeReferences,
15    NodeCompactIndexable,
16    NodeCount,
17    NodeIndexable,
18    Visitable,
19    EdgeRef,
20    Data,
21    GraphProp,
22};
23
24/// An edge-reversing graph adaptor.
25///
26/// All edges have the opposite direction with `Reversed`.
27#[derive(Copy, Clone, Debug)]
28pub struct Reversed<G>(pub G);
29
30impl<G: GraphBase> GraphBase for Reversed<G> {
31    type NodeId = G::NodeId;
32    type EdgeId = G::EdgeId;
33}
34
35impl<G: GraphRef> GraphRef for Reversed<G> { }
36
37Data!{delegate_impl [[G], G, Reversed<G>, access0]}
38
39impl<G> IntoNeighbors for Reversed<G>
40    where G: IntoNeighborsDirected
41{
42    type Neighbors = G::NeighborsDirected;
43    fn neighbors(self, n: G::NodeId) -> G::NeighborsDirected
44    {
45        self.0.neighbors_directed(n, Incoming)
46    }
47}
48
49impl<G> IntoNeighborsDirected for Reversed<G>
50    where G: IntoNeighborsDirected
51{
52    type NeighborsDirected = G::NeighborsDirected;
53    fn neighbors_directed(self, n: G::NodeId, d: Direction)
54        -> G::NeighborsDirected
55    {
56        self.0.neighbors_directed(n, d.opposite())
57    }
58}
59
60impl<G: Visitable> Visitable for Reversed<G>
61{
62    type Map = G::Map;
63    fn visit_map(&self) -> G::Map {
64        self.0.visit_map()
65    }
66    fn reset_map(&self, map: &mut Self::Map) {
67        self.0.reset_map(map);
68    }
69}
70
71
72/// A reversed edge reference
73#[derive(Copy, Clone, Debug)]
74pub struct ReversedEdgeReference<R>(R);
75
76/// An edge reference
77impl<R> EdgeRef for ReversedEdgeReference<R>
78    where R: EdgeRef,
79{
80    type NodeId = R::NodeId;
81    type EdgeId = R::EdgeId;
82    type Weight = R::Weight;
83    fn source(&self) -> Self::NodeId {
84        self.0.target()
85    }
86    fn target(&self) -> Self::NodeId {
87        self.0.source()
88    }
89    fn weight(&self) -> &Self::Weight {
90        self.0.weight()
91    }
92    fn id(&self) -> Self::EdgeId {
93        self.0.id()
94    }
95}
96
97impl<G> IntoEdgeReferences for Reversed<G>
98    where G: IntoEdgeReferences
99{
100    type EdgeRef = ReversedEdgeReference<G::EdgeRef>;
101    type EdgeReferences = ReversedEdgeReferences<G::EdgeReferences>;
102    fn edge_references(self) -> Self::EdgeReferences {
103        ReversedEdgeReferences {
104            iter: self.0.edge_references(),
105        }
106    }
107}
108
109/// A reversed edge references iterator.
110pub struct ReversedEdgeReferences<I> {
111    iter: I,
112}
113
114impl<I> Iterator for ReversedEdgeReferences<I>
115    where I: Iterator,
116          I::Item: EdgeRef,
117{
118    type Item = ReversedEdgeReference<I::Item>;
119    fn next(&mut self) -> Option<Self::Item> {
120        self.iter.next().map(ReversedEdgeReference)
121    }
122}
123
124macro_rules! access0 {
125    ($e:expr) => ($e.0)
126}
127
128NodeIndexable!{delegate_impl [[G], G, Reversed<G>, access0]}
129NodeCompactIndexable!{delegate_impl [[G], G, Reversed<G>, access0]}
130IntoNodeIdentifiers!{delegate_impl [[G], G, Reversed<G>, access0]}
131IntoNodeReferences!{delegate_impl [[G], G, Reversed<G>, access0]}
132GraphProp!{delegate_impl [[G], G, Reversed<G>, access0]}
133NodeCount!{delegate_impl [[G], G, Reversed<G>, access0]}
134
135
petgraph/visit/reversed.rs

petgraph/visit/
reversed.rs
