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Improve graphlib::iterators::Dijkstra API #57

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727f7bd
Fix #56 - Don't consume self in Dijkstra::get_path_to
cemeyer Dec 9, 2021
de406ab
Fix #56 - Drop unneeded mut from Dijkstra::get_distance
cemeyer Dec 9, 2021
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22 changes: 8 additions & 14 deletions src/iterators/dijkstra.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -52,7 +52,6 @@ impl Ord for VertexMeta {
pub struct Dijkstra<'a, T> {
source: &'a VertexId,
iterable: &'a Graph<T>,
iterator: VecDeque<VertexId>,
distances: HashMap<VertexId, f32>,
previous: HashMap<VertexId, Option<VertexId>>,
}
Expand All @@ -74,7 +73,6 @@ impl<'a, T> Dijkstra<'a, T> {
let mut instance = Dijkstra {
source: src,
iterable: graph,
iterator: VecDeque::with_capacity(graph.vertex_count()),
distances: HashMap::with_capacity(graph.vertex_count()),
previous: HashMap::with_capacity(graph.vertex_count()),
};
Expand All @@ -97,40 +95,36 @@ impl<'a, T> Dijkstra<'a, T> {
Ok(())
}

pub fn get_path_to(mut self, vert: &'a VertexId) -> Result<VertexIter, GraphErr> {
pub fn get_path_to(&self, vert: &'a VertexId) -> Result<VertexIter<'a>, GraphErr> {
if self.iterable.fetch(vert).is_none() {
return Err(GraphErr::NoSuchVertex);
}

if self.previous.contains_key(vert) {
let mut cur_vert = Some(vert);
self.iterator.clear();
let mut iterator = VecDeque::new();

while cur_vert.is_some() {
self.iterator.push_front(*cur_vert.unwrap());
while let Some(cur_vert_inner) = cur_vert {
iterator.push_front(*cur_vert_inner);

match self.previous.get(cur_vert.unwrap()) {
match self.previous.get(cur_vert_inner) {
Some(v) => cur_vert = v.as_ref(),
None => cur_vert = None,
}
}

return Ok(VertexIter(Box::new(OwningIterator::new(self.iterator))));
return Ok(VertexIter(Box::new(OwningIterator::new(iterator))));
}

Ok(VertexIter(Box::new(iter::empty())))
}

pub fn get_distance(&mut self, vert: &'a VertexId) -> Result<f32, GraphErr> {
pub fn get_distance(&self, vert: &'a VertexId) -> Result<f32, GraphErr> {
if self.iterable.fetch(vert).is_none() {
return Err(GraphErr::NoSuchVertex);
}

if self.distances.contains_key(vert) {
return Ok(*self.distances.get(vert).unwrap());
}

Ok(f32::MAX)
Ok(self.distances.get(vert).copied().unwrap_or(f32::MAX))
}

fn calc_distances(&mut self) {
Expand Down