support hash of enum using underlying_type by default.

can be forced to use hash with the actual enum type
#define RXCPP_FORCE_HASH_ENUM 1

3 files changed, 94 insertions, 9 deletions

diff --git a/Rx/v2/src/rxcpp/rx-includes.hpp b/Rx/v2/src/rxcpp/rx-includes.hpp
index cc473f6..51a96eb 100644
--- a/Rx/v2/src/rxcpp/rx-includes.hpp
+++ b/Rx/v2/src/rxcpp/rx-includes.hpp
@@ -55,12 +55,31 @@
 
 #endif
 
+//
+// control std::hash<> of enum
+// force with RXCPP_FORCE_HASH_ENUM & RXCPP_FORCE_HASH_ENUM_UNDERLYING
+// in time use ifdef to detect library support for std::hash<> of enum
+//
+#define RXCPP_HASH_ENUM 0
+#define RXCPP_HASH_ENUM_UNDERLYING 1
+
 #if !defined(WINAPI_FAMILY) || (WINAPI_FAMILY == WINAPI_FAMILY_DESKTOP_APP)
 #define RXCPP_USE_WINRT 0
 #else
 #define RXCPP_USE_WINRT 1
 #endif
 
+#if defined(__APPLE__) && defined(__MACH__)
+#include <TargetConditionals.h>
+#if (TARGET_OS_IPHONE == 1) || (TARGET_IPHONE_SIMULATOR == 1)
+#define RXCPP_ON_IOS
+#endif
+#endif
+
+#if defined(__ANDROID__)
+#define RXCPP_ON_ANDROID
+#endif
+
 #if defined(RXCPP_FORCE_USE_VARIADIC_TEMPLATES)
 #undef RXCPP_USE_VARIADIC_TEMPLATES
 #define RXCPP_USE_VARIADIC_TEMPLATES RXCPP_FORCE_USE_VARIADIC_TEMPLATES
@@ -81,20 +100,29 @@
 #define RXCPP_USE_WINRT RXCPP_FORCE_USE_WINRT
 #endif
 
-#if defined(_MSC_VER) && !RXCPP_USE_VARIADIC_TEMPLATES
-// resolve args needs enough to store all the possible resolved args
-#define _VARIADIC_MAX 10
+#if defined(RXCPP_FORCE_HASH_ENUM)
+#undef RXCPP_HASH_ENUM
+#define RXCPP_HASH_ENUM RXCPP_FORCE_HASH_ENUM
 #endif
 
-#if defined(__APPLE__) && defined(__MACH__)
-#include <TargetConditionals.h>
-#if (TARGET_OS_IPHONE == 1) || (TARGET_IPHONE_SIMULATOR == 1)
-#define RXCPP_ON_IOS
+#if defined(RXCPP_FORCE_HASH_ENUM_UNDERLYING)
+#undef RXCPP_HASH_ENUM_UNDERLYING
+#define RXCPP_HASH_ENUM_UNDERLYING RXCPP_FORCE_HASH_ENUM_UNDERLYING
 #endif
+
+#if defined(RXCPP_FORCE_ON_IOS)
+#undef RXCPP_ON_IOS
+#define RXCPP_ON_IOS RXCPP_FORCE_ON_IOS
 #endif
 
-#if defined(__ANDROID__)
-#define RXCPP_ON_ANDROID
+#if defined(RXCPP_FORCE_ON_ANDROID)
+#undef RXCPP_ON_ANDROID
+#define RXCPP_ON_ANDROID RXCPP_FORCE_ON_ANDROID
+#endif
+
+#if defined(_MSC_VER) && !RXCPP_USE_VARIADIC_TEMPLATES
+// resolve args needs enough to store all the possible resolved args
+#define _VARIADIC_MAX 10
 #endif
 
 #pragma push_macro("min")
diff --git a/Rx/v2/src/rxcpp/rx-util.hpp b/Rx/v2/src/rxcpp/rx-util.hpp
index d25b76f..a4fb758 100644
--- a/Rx/v2/src/rxcpp/rx-util.hpp
+++ b/Rx/v2/src/rxcpp/rx-util.hpp
@@ -705,9 +705,16 @@ namespace rxu=util;
 template <class T, typename = void> 
 struct filtered_hash;
 
+#if RXCPP_HASH_ENUM
 template <class T> 
 struct filtered_hash<T, typename std::enable_if<std::is_enum<T>::value>::type> : std::hash<T> {
 };
+#elif RXCPP_HASH_ENUM_UNDERLYING
+template <class T> 
+struct filtered_hash<T, typename std::enable_if<std::is_enum<T>::value>::type> : std::hash<typename std::underlying_type<T>::type> {
+};
+#endif
+
 template <class T> 
 struct filtered_hash<T, typename std::enable_if<std::is_integral<T>::value>::type> : std::hash<T> {
 };
diff --git a/Rx/v2/test/operators/distinct.cpp b/Rx/v2/test/operators/distinct.cpp
index 77c69cd..84ce6ea 100644
--- a/Rx/v2/test/operators/distinct.cpp
+++ b/Rx/v2/test/operators/distinct.cpp
@@ -338,4 +338,54 @@ SCENARIO("distinct - strings", "[distinct][operators]"){
 
         }
     }
+}
+
+SCENARIO("distinct - enum", "[distinct][operators]"){
+    enum Value {
+        A,
+        B,
+        C
+    };
+    GIVEN("a source"){
+        auto sc = rxsc::make_test();
+        auto w = sc.create_worker();
+        const rxsc::test::messages<Value> on;
+
+        auto xs = sc.make_hot_observable({
+            on.next(150, Value::A),
+            on.next(210, Value::A),
+            on.next(220, Value::B),
+            on.next(230, Value::B),
+            on.next(240, Value::B),
+            on.completed(250)
+        });
+
+        WHEN("distinct values are taken"){
+
+            auto res = w.start(
+                    [xs]() {
+                        return xs.distinct();
+                    }
+            );
+
+            THEN("the output only contains distinct items sent while subscribed"){
+                auto required = rxu::to_vector({
+                    on.next(210, Value::A),
+                    on.next(220, Value::B),
+                    on.completed(250)
+                });
+                auto actual = res.get_observer().messages();
+                REQUIRE(required == actual);
+            }
+
+            THEN("there was 1 subscription/unsubscription to the source"){
+                auto required = rxu::to_vector({
+                    on.subscribe(200, 250)
+                });
+                auto actual = xs.subscriptions();
+                REQUIRE(required == actual);
+            }
+
+        }
+    }
 }
\ No newline at end of file