Core/Utils: Added .contains member function to FlatSet

(cherry picked from commit a27e3a52a0cdfae8cf5cbb787e944f4f76319f26)

Author: Shauren

src/common/Containers/FlatSet.h

@@ -39,21 +39,28 @@ class FlatSet
     auto end()  { return _storage.end(); }
     auto end() const { return _storage.end(); }
 
+    bool contains(Key const& value) const
+    {
+        return std::binary_search(this->begin(), this->end(), value, Compare());
+    }
+
     auto find(Key const& value) const
     {
+        auto compare = Compare();
         auto end = this->end();
-        auto itr = std::lower_bound(this->begin(), end, value, Compare());
-        if (itr != end && Compare()(value, *itr))
+        auto itr = std::lower_bound(this->begin(), end, value, compare);
+        if (itr != end && compare(value, *itr))
             itr = end;
 
         return itr;
     }
 
     auto find(Key const& value)
     {
+        auto compare = Compare();
         auto end = this->end();
-        auto itr = std::lower_bound(this->begin(), end, value, Compare());
-        if (itr != end && Compare()(value, *itr))
+        auto itr = std::lower_bound(this->begin(), end, value, compare);
+        if (itr != end && compare(value, *itr))
             itr = end;
 
         return itr;
@@ -63,9 +70,10 @@ class FlatSet
     std::pair<iterator, bool> emplace(Args&&... args)
     {
         Key newElement(std::forward<Args>(args)...);
+        auto compare = Compare();
         auto end = this->end();
-        auto itr = std::lower_bound(this->begin(), end, newElement, Compare());
-        if (itr != end && !Compare()(newElement, *itr))
+        auto itr = std::lower_bound(this->begin(), end, newElement, compare);
+        if (itr != end && !compare(newElement, *itr))
             return { itr, false };
 
         return { _storage.emplace(itr, std::move(newElement)), true };
@@ -88,15 +96,8 @@ class FlatSet
 
     void shrink_to_fit() { _storage.shrink_to_fit(); }
 
-    friend bool operator==(FlatSet const& left, FlatSet const& right)
-    {
-        return left._storage == right._storage;
-    }
-
-    friend bool operator!=(FlatSet const& left, FlatSet const& right)
-    {
-        return !(left == right);
-    }
+    friend std::strong_ordering operator<=>(FlatSet const& left, FlatSet const& right) = default;
+    friend bool operator==(FlatSet const& left, FlatSet const& right) = default;
 
 private:
     KeyContainer _storage;