Merge pull request #50 from serge-sans-paille/fix/enum-class-keys

Fix/enum class keys
serge-sans-paille · Jul 9, 2018 · 325449a · 325449a
2 parents d0a9d3f + 1e1b029
commit 325449a
Show file tree

Hide file tree

Showing 2 changed files with 11 additions and 2 deletions.
diff --git a/include/frozen/bits/elsa.h b/include/frozen/bits/elsa.h
@@ -26,11 +26,11 @@
 namespace frozen {
 
 template <class T> struct elsa {
-  static_assert(std::is_integral<T>::value,
+  static_assert(std::is_integral<T>::value || std::is_enum<T>::value,
                 "only supports integral types, specialize for other types");
 
   constexpr std::size_t operator()(T const &value, std::size_t seed) const {
-    std::size_t key = seed ^ value;
+    std::size_t key = seed ^ static_cast<std::size_t>(value);
     key = (~key) + (key << 21); // key = (key << 21) - key - 1;
     key = key ^ (key >> 24);
     key = (key + (key << 3)) + (key << 8); // key * 265

diff --git a/tests/test_unordered_set.cpp b/tests/test_unordered_set.cpp
@@ -125,6 +125,15 @@ TEST_CASE("frozen::unordered_set<int> <> std::unordered_set",
 
 }
 
+TEST_CASE("frozen::unordered_set with enum keys", "[unordered_set]") {
+  enum class some_enum {
+    A,B,C
+  };
+  constexpr frozen::unordered_set<some_enum, 2> frozen_set = { some_enum::A, some_enum::B };
+  REQUIRE(frozen_set.count(some_enum::A) == 1);
+  REQUIRE(frozen_set.count(some_enum::C) == 0);
+}
+
 TEST_CASE("frozen::unordered_set <> frozen::make_unordered_set", "[unordered_set]") {
   constexpr frozen::unordered_set<int, 129> frozen_set = { INIT_SEQ };
   constexpr auto frozen_set2 = frozen::make_unordered_set<int>({INIT_SEQ});