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use std::collections::{BTreeMap, HashMap, HashSet, VecDeque};
use error::*;
pub trait Vertex: Clone + Sync {
fn index(&self) -> usize;
fn dot_label(&self) -> String;
}
pub trait Edge: Clone + Sync {
fn head(&self) -> usize;
fn tail(&self) -> usize;
fn dot_label(&self) -> String;
}
#[derive(Clone, Debug, Deserialize, Eq, Hash, Ord, PartialEq, PartialOrd, Serialize)]
pub struct NullVertex {
index: usize
}
impl NullVertex {
pub fn new(index: usize) -> NullVertex {
NullVertex {
index: index
}
}
}
impl Vertex for NullVertex {
fn index(&self) -> usize { self.index }
fn dot_label(&self) -> String { format!("{}", self.index) }
}
#[derive(Clone, Debug, Deserialize, Eq, Hash, Ord, PartialEq, PartialOrd, Serialize)]
pub struct NullEdge {
head: usize,
tail: usize
}
impl NullEdge {
pub fn new(head: usize, tail: usize) -> NullEdge {
NullEdge {
head: head,
tail: tail
}
}
}
impl Edge for NullEdge {
fn head(&self) -> usize { self.head }
fn tail(&self) -> usize { self.tail }
fn dot_label(&self) -> String { format!("{} -> {}", self.head, self.tail) }
}
#[derive(Clone, Debug, Deserialize, Eq, Hash, Ord, PartialEq, PartialOrd, Serialize)]
pub struct Graph<V: Vertex, E: Edge> {
head: Option<usize>,
vertices: BTreeMap<usize, V>,
edges: BTreeMap<(usize, usize), E>,
edges_out: BTreeMap<usize, Vec<E>>,
edges_in: BTreeMap<usize, Vec<E>>
}
impl<V, E> Graph<V, E> where V: Vertex, E: Edge {
pub fn new() -> Graph<V, E> {
Graph {
head: None,
vertices: BTreeMap::new(),
edges: BTreeMap::new(),
edges_out: BTreeMap::new(),
edges_in: BTreeMap::new()
}
}
pub fn num_vertices(&self) -> usize {
self.vertices.len()
}
pub fn has_vertex(&self, index: usize) -> bool {
self.vertices.contains_key(&index)
}
pub fn set_head(&mut self, index: usize) -> Result<()> {
if !self.vertices.contains_key(&index) {
return Err("Cannot set head for index that does not exist".into());
}
self.head = Some(index);
Ok(())
}
pub fn head(&self) -> Option<usize> {
self.head
}
pub fn remove_vertex(&mut self, index: usize) -> Result<()> {
if !self.has_vertex(index) {
bail!("vertex does not exist");
}
self.vertices.remove(&index);
let mut edges = Vec::new();
if let Some(edges_out) = self.edges_out.get(&index) {
for edge in edges_out {
edges.push((edge.head(), edge.tail()));
}
};
if let Some(edges_in) = self.edges_in.get(&index) {
for edge in edges_in {
edges.push((edge.head(), edge.tail()));
}
};
for edge in edges {
self.remove_edge(edge.0, edge.1)?;
}
self.edges_in.remove(&index);
self.edges_out.remove(&index);
Ok(())
}
pub fn remove_edge(&mut self, head: usize, tail: usize) -> Result<()> {
if !self.edges.contains_key(&(head, tail)) {
bail!("edge does not exist");
}
self.edges.remove(&(head, tail));
let mut index = None;
let edges_out = self.edges_out.get_mut(&head).unwrap();
for (i, edge) in edges_out.iter().enumerate() {
if edge.head() == head && edge.tail() == tail {
index = Some(i);
break;
}
}
edges_out.remove(index.unwrap());
let mut index = None;
let edges_in = self.edges_in.get_mut(&tail).unwrap();
for (i, edge) in edges_in.iter().enumerate() {
if edge.head() == head && edge.tail() == tail {
index = Some(i);
break;
}
}
edges_in.remove(index.unwrap());
Ok(())
}
pub fn insert_vertex(&mut self, v: V) -> Result<()> {
if self.vertices.contains_key(&v.index()) {
return Err("duplicate vertex index".into());
}
self.vertices.insert(v.index(), v.clone());
self.edges_out.insert(v.index(), Vec::new());
self.edges_in.insert(v.index(), Vec::new());
Ok(())
}
pub fn insert_edge(&mut self, edge: E) -> Result<()> {
if self.edges.contains_key(&(edge.head(), edge.tail())) {
return Err("duplicate edge".into());
}
self.edges.insert((edge.head(), edge.tail()), edge.clone());
self.edges_out.get_mut(&edge.head()).map(|v| v.push(edge.clone()));
self.edges_in.get_mut(&edge.tail()).map(|v| v.push(edge.clone()));
Ok(())
}
pub fn successors(&self, index: usize) -> Result<Vec<&V>> {
if !self.vertices.contains_key(&index) {
bail!("Vertex {} does not exist and therefor has no successors", index);
}
let vertices = self.edges_out[&index]
.iter()
.map(|e| self.vertex(e.tail()));
Ok(vertices.fold(Vec::new(), |mut v, vx| {
v.push(vx.unwrap());
v
}))
}
pub fn predecessors(&self, index: usize) -> Result<Vec<&V>> {
if !self.vertices.contains_key(&index) {
bail!("Vertex {} does not exist and therefor has no predecessors", index);
}
let vertices = self.edges_in[&index]
.iter()
.map(|e| self.vertex(e.head()));
Ok(vertices.fold(Vec::new(), |mut v, vx| {
v.push(vx.unwrap());
v
}))
}
pub fn compute_post_order(&self, root: usize) -> Result<Vec<usize>> {
let mut visited: HashSet<usize> = HashSet::new();
let mut order: Vec<usize> = Vec::new();
fn dfs_walk<V: Vertex, E: Edge>(
graph: &Graph<V, E>,
node: usize,
visited: &mut HashSet<usize>,
order: &mut Vec<usize>
) -> Result<()> {
visited.insert(node);
for successor in graph.edges_out(node)? {
if !visited.contains(&successor.tail()) {
dfs_walk(
graph,
successor.tail(),
visited,
order
)?;
}
}
order.push(node);
Ok(())
}
dfs_walk(self, root, &mut visited, &mut order)?;
Ok(order)
}
pub fn compute_dominance_frontiers(&self, start_index: usize)
-> Result<HashMap<usize, HashSet<usize>>> {
let mut df: HashMap<usize, HashSet<usize>> = HashMap::new();
for vertex in &self.vertices {
df.insert(*vertex.0, HashSet::new());
}
let idoms = self.compute_immediate_dominators(start_index)?;
for vertex in &self.vertices {
let vertex_index: usize = *vertex.0;
if self.edges_in[&vertex_index].len() >= 2 {
for edge in &self.edges_in[&vertex_index] {
let mut runner = edge.head();
while idoms.contains_key(&edge.head()) && runner != idoms[&edge.head()] {
df.get_mut(&runner).unwrap().insert(vertex_index);
if !idoms.contains_key(&runner) {
break;
}
runner = idoms[&runner];
}
}
}
}
Ok(df)
}
pub fn compute_immediate_dominators(&self, start_index: usize)
-> Result<HashMap<usize, usize>> {
let mut idoms: HashMap<usize, usize> = HashMap::new();
let dominators = self.compute_dominators(start_index)?;
for vertex in &self.vertices {
let vertex_index: usize = *vertex.0;
let mut sdoms = dominators[&vertex_index].clone();
sdoms.remove(&vertex_index);
for sdom in &sdoms {
let mut is_idom = true;
for sdom2 in &sdoms {
if sdom == sdom2 {
continue;
}
if dominators[sdom2].contains(sdom) {
is_idom = false;
break;
}
}
if is_idom {
idoms.insert(vertex_index, *sdom);
break;
}
}
}
Ok(idoms)
}
pub fn compute_dominators(&self, start_index: usize)
-> Result<HashMap<usize, HashSet<usize>>> {
if !self.vertices.contains_key(&start_index) {
bail!("vertex {} not in graph", start_index);
}
let mut dominators: HashMap<usize, HashSet<usize>> = HashMap::new();
{
let mut set = HashSet::new();
set.insert(start_index);
dominators.insert(start_index, set);
}
let mut queue = VecDeque::new();
for edge in &self.edges_out[&start_index] {
queue.push_back(edge.tail());
}
let dag = self.compute_acyclic(start_index)?;
let predecessors = dag.compute_predecessors()?;
while !queue.is_empty() {
let vertex_index: usize = queue.pop_front().unwrap();
let mut predecessors_set = true;
for predecessor in &predecessors[&vertex_index] {
if !dominators.contains_key(predecessor) {
if !queue.contains(predecessor) {
queue.push_back(*predecessor);
}
predecessors_set = false;
}
}
if !predecessors_set {
queue.push_back(vertex_index);
continue;
}
let mut doms: HashSet<usize> = match dag.edges_in(vertex_index)
.unwrap()
.first() {
Some(predecessor_edge) => dominators[&predecessor_edge.head()].clone(),
None => HashSet::new()
};
for edge in &self.edges_in[&vertex_index] {
if predecessors[&vertex_index].contains(&edge.head()) {
doms = &doms & &dominators[&edge.head()];
}
}
doms.insert(vertex_index);
dominators.insert(vertex_index, doms.clone());
for edge in &dag.edges_out[&vertex_index] {
if !queue.contains(&edge.tail()) {
queue.push_back(edge.tail());
}
}
}
Ok(dominators)
}
pub fn compute_predecessors(&self) -> Result<HashMap<usize, HashSet<usize>>> {
let mut predecessors: HashMap<usize, HashSet<usize>> = HashMap::new();
let mut queue: VecDeque<usize> = VecDeque::new();
for vertex in &self.vertices {
let mut preds = HashSet::new();
for edge in self.edges_in(*vertex.0).unwrap() {
preds.insert(edge.head());
}
predecessors.insert(*vertex.0, preds);
queue.push_back(*vertex.0);
}
while !queue.is_empty() {
let vertex_index = queue.pop_front().unwrap();
let mut to_add: Vec<usize> = Vec::new();
{
let this_predecessors = &predecessors[&vertex_index];
for predecessor in &predecessors[&vertex_index] {
for pp in &predecessors[predecessor] {
if !this_predecessors.contains(pp) {
to_add.push(*pp);
}
}
}
}
let this_predecessors = predecessors.get_mut(&vertex_index).unwrap();
for predecessor in &to_add {
this_predecessors.insert(*predecessor);
}
if !to_add.is_empty() {
for successor in self.edges_out(vertex_index).unwrap() {
queue.push_back(successor.tail());
}
}
}
Ok(predecessors)
}
pub fn compute_acyclic(&self, start_index: usize) -> Result<Graph<NullVertex, NullEdge>> {
let mut graph = Graph::new();
for vertex in &self.vertices {
graph.insert_vertex(NullVertex::new(*vertex.0))?;
}
let predecessors = self.compute_predecessors()?;
let mut visited = HashSet::new();
let mut queue = VecDeque::new();
queue.push_back(start_index);
while !queue.is_empty() {
let vertex_index = queue.pop_front().unwrap();
visited.insert(vertex_index);
let vertex_predecessors = &predecessors[&vertex_index];
for edge in &self.edges_out[&vertex_index] {
if visited.contains(&edge.tail()) && vertex_predecessors.contains(&edge.tail()) {
continue;
}
if !visited.contains(&edge.tail()) && !queue.contains(&edge.tail()) {
queue.push_back(edge.tail());
}
graph.insert_edge(NullEdge::new(edge.head(), edge.tail()))?;
}
}
Ok(graph)
}
pub fn vertices(&self) -> Vec<&V> {
self.vertices.values().collect()
}
pub fn vertices_mut(&mut self) -> Vec<&mut V> {
let mut vec = Vec::new();
for vertex in &mut self.vertices {
vec.push(vertex.1);
}
vec
}
pub fn vertex(&self, index: usize) -> Result<&V> {
self.vertices
.get(&index)
.ok_or(ErrorKind::GraphVertexNotFound(index).into())
}
pub fn vertex_mut(&mut self, index: usize) -> Result<&mut V> {
self.vertices
.get_mut(&index)
.ok_or(ErrorKind::GraphVertexNotFound(index).into())
}
pub fn edge(&self, head: usize, tail: usize) -> Result<&E> {
self.edges
.get(&(head, tail))
.ok_or(ErrorKind::GraphEdgeNotFound(head, tail).into())
}
pub fn edge_mut(&mut self, head: usize, tail: usize) -> Result<&mut E> {
self.edges
.get_mut(&(head, tail))
.ok_or(ErrorKind::GraphEdgeNotFound(head, tail).into())
}
pub fn edges(&self) -> Vec<&E> {
self.edges.values().collect()
}
pub fn edges_mut(&mut self) -> Vec<&mut E> {
let mut vec = Vec::new();
for edge in &mut self.edges {
vec.push(edge.1);
}
vec
}
pub fn edges_out(&self, index: usize) -> Result<&Vec<E>> {
self.edges_out
.get(&index)
.ok_or(ErrorKind::GraphVertexNotFound(index).into())
}
pub fn edges_in(&self, index: usize) -> Result<&Vec<E>> {
self.edges_in
.get(&index)
.ok_or(ErrorKind::GraphVertexNotFound(index).into())
}
pub fn dot_graph(&self) -> String {
let vertices = self.vertices.iter().map(|v| {
let label = v.1.dot_label().replace("\n", "\\l");
format!("{} [shape=\"box\", label=\"{}\", style=\"filled\", fillcolor=\"#ffddcc\"];", v.1.index(), label)
}).collect::<Vec<String>>();
let edges = self.edges.iter().map(|e| {
let label = e.1.dot_label().replace("\n", "\\l");
format!("{} -> {} [label=\"{}\"];", e.1.head(), e.1.tail(), label)
}).collect::<Vec<String>>();
let mut options = Vec::new();
options.push("graph [fontname = \"Courier New\", splines=\"polyline\"]");
options.push("node [fontname = \"Courier New\"]");
options.push("edge [fontname = \"Courier New\"]");
format!("digraph G {{\n{}\n\n{}\n{}\n}}", options.join("\n"), vertices.join("\n"), edges.join("\n"))
}
}