Implement FlurryHashSet insert() and contains()

src/lib.rs

@@ -197,6 +197,8 @@
 mod node;
 use node::*;
 
+pub mod set;
+
 use crossbeam::epoch::{Atomic, Guard, Owned, Shared};
 use std::collections::hash_map::RandomState;
 use std::hash::{BuildHasher, Hash};

src/set/mod.rs

@@ -0,0 +1,41 @@
+//! A concurrent hash set backed by FlurryHashMap.
+
+use crossbeam::epoch;
+use std::collections::hash_map::RandomState;
+use std::hash::Hash;
+
+use crate::FlurryHashMap;
+
+/// A concurrent hash set.
+#[derive(Debug)]
+pub struct FlurryHashSet<T, S = RandomState> {
+    map: FlurryHashMap<T, (), S>,
+}
+
+impl<T> FlurryHashSet<T, RandomState>
+where
+    T: Sync + Send + Clone + Hash + Eq,
+{
+    /// Creates a new, empty set with the default initial table size (16).
+    pub fn new() -> Self {
+        Self {
+            map: FlurryHashMap::<T, ()>::new(),
+        }
+    }
+
+    /// Adds a value to the set.
+    ///
+    /// If the set did not have this value present, true is returned.
+    ///
+    /// If the set did have this value present, false is returned.
+    pub fn insert(&self, value: T) -> bool {
+        let guard = epoch::pin();
+        let old = self.map.insert(value, (), &guard);
+        old.is_none()
+    }
+
+    /// Returns true if the set contains a value.
+    pub fn contains(&self, value: &T) -> bool {
+        self.map.contains_key(value)
+    }
+}

tests/set.rs

@@ -0,0 +1,25 @@
+use flurry::set::FlurryHashSet;
+
+#[test]
+fn new() {
+    let _set = FlurryHashSet::<usize>::new();
+}
+
+#[test]
+fn insert() {
+    let set = FlurryHashSet::<usize>::new();
+    let did_set = set.insert(42);
+    assert!(did_set);
+
+    let did_set = set.insert(42);
+    assert!(!did_set);
+}
+
+#[test]
+fn insert_contains() {
+    let set = FlurryHashSet::<usize>::new();
+    set.insert(42);
+
+    assert!(set.contains(&42));
+    assert!(!set.contains(&43));
+}