providing automatic serializability to/fro streams only makes sense i…

…f type's streamability is bidirectional.
m-a-d-n-e-s-s · May 1, 2018 · 99aea9a · 99aea9a
1 parent bb443fa
commit 99aea9a
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Showing 2 changed files with 8 additions and 4 deletions.
diff --git a/src/madness/world/text_fstream_archive.h b/src/madness/world/text_fstream_archive.h
@@ -99,7 +99,7 @@ namespace madness {
             /// \param[in] t Location of the data to be written.
             /// \param[in] n The number of data items to be written.
             template <class T>
-            typename std::enable_if< madness::is_ostreammable<T>::value >::type
+            typename std::enable_if< madness::is_iostreammable_v<T> >::type
             store(const T* t, long n) const {
                 using madness::operator<<;
                 for (long i=0; i<n; ++i)
@@ -205,7 +205,7 @@ namespace madness {
             /// \param[out] t Where to put the loaded data.
             /// \param[in] n The number of data items to be loaded.
             template <class T>
-            typename std::enable_if< madness::is_istreammable<T>::value >::type
+            typename std::enable_if< madness::is_iostreammable_v<T> >::type
             load(T* t, long n) const {
                 for (long i=0; i<n; ++i) is >> t[i];
                 eat_eol();

diff --git a/src/madness/world/type_traits.h b/src/madness/world/type_traits.h
@@ -93,11 +93,15 @@ using std::void_t;
     struct is_ostreammable : std::false_type {};
     template <typename T>
     struct is_ostreammable<T, meta::void_t<decltype(std::declval<std::ostream&>() << std::declval<const T&>())>> : std::true_type {};
+    template <typename T> constexpr bool is_ostreammable_v = is_ostreammable<T>::value;
     /// True for types that are "deserialiable" from an std::istream
     template <typename T, typename = void>
     struct is_istreammable : std::false_type {};
     template <typename T>
     struct is_istreammable<T, meta::void_t<decltype(std::declval<std::istream&>() >> std::declval<T&>())>> : std::true_type {};
+    template <typename T> constexpr bool is_istreammable_v = is_ostreammable<T>::value;
+    /// providing automatic support for serializing to/from std streams requires bidirectional streammability
+    template <typename T> constexpr bool is_iostreammable_v = is_istreammable_v<T> && is_ostreammable_v<T>;
 
     template <typename T> constexpr bool is_always_serializable =
     std::is_arithmetic<T>::value || \
@@ -137,9 +141,9 @@ using std::void_t;
     template <typename T>
     struct is_serializable<archive::VectorInputArchive, T, std::enable_if_t<is_trivially_serializable<T>::value>> : std::true_type {};
     template <typename T>
-    struct is_serializable<archive::TextFstreamOutputArchive, T, std::enable_if_t<is_ostreammable<T>::value>> : std::true_type {};
+    struct is_serializable<archive::TextFstreamOutputArchive, T, std::enable_if_t<is_iostreammable_v<T>>> : std::true_type {};
     template <typename T>
-    struct is_serializable<archive::TextFstreamInputArchive, T, std::enable_if_t<is_istreammable<T>::value>> : std::true_type {};
+    struct is_serializable<archive::TextFstreamInputArchive, T, std::enable_if_t<is_iostreammable_v<T>>> : std::true_type {};
     template <typename T>
     struct is_serializable<archive::MPIRawOutputArchive, T, std::enable_if_t<is_trivially_serializable<T>::value>> : std::true_type {};
     template <typename T>