add missing tuple c++ replacement for unittests

Author: paul-szczepanek-arm

UNITTESTS/target_h/platform/cxxsupport/mstd_tuple

@@ -0,0 +1,93 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2019 ARM Limited
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES LEOR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#ifndef MSTD_TUPLE_
+#define MSTD_TUPLE_
+
+/* <mstd_tuple>
+ *
+ * - includes toolchain's <tuple>
+ * - For all toolchains, C++17 backports:
+ *   - mstd::apply
+ *   - mstd::make_from_tuple
+ */
+
+#include <tuple>
+
+#if __cpp_lib_apply < 201603 || __cpp_lib_make_from_tuple < 201606
+#include <mstd_utility> // integer_sequence
+#endif
+#if __cpp_lib_apply < 201603
+#include <mstd_functional> // invoke
+#endif
+
+namespace mstd {
+using std::tuple;
+using std::ignore;
+using std::make_tuple;
+using std::forward_as_tuple;
+using std::tie;
+using std::tuple_cat;
+using std::tuple_size;
+using std::tuple_element;
+using std::tuple_element_t;
+using std::get;
+
+// [tuple.apply]
+#if __cpp_lib_apply >= 201603
+using std::apply;
+#else
+namespace impl {
+template <class F, class Tuple, size_t... I>
+invoke_result_t<F, tuple_element_t<I, Tuple>...> apply(F&& f, Tuple&& t, std::index_sequence<I...>)
+{
+    return mstd::invoke(std::forward<F>(f), std::get<I>(std::forward<Tuple>(t))...);
+}
+}
+
+// apply<F, Tuple> - works also for tuple-like objects such as array or pair
+// user-defined types can specialize std::get and std::tuple_size to make this work
+template <class F, class Tuple>
+auto apply(F&& f, Tuple&& t) ->
+decltype(impl::apply(std::forward<F>(f), std::forward<Tuple>(t), std::make_index_sequence<tuple_size<remove_reference_t<Tuple>>::value>{}))
+{
+    return impl::apply(std::forward<F>(f), std::forward<Tuple>(t),
+                       std::make_index_sequence<std::tuple_size<std::remove_reference_t<Tuple>>::value>{});
+}
+#endif
+
+#if __cpp_lib_make_from_tuple >= 201606
+using std::make_from_tuple;
+#else
+namespace impl {
+template <class T, class Tuple, size_t... I>
+T make_from_tuple(Tuple&& t, std::index_sequence<I...>)
+{
+    return T(std::get<I>(std::forward<Tuple>(t))...);
+}
+}
+
+template <class T, class Tuple>
+T make_from_tuple(Tuple&& t)
+{
+    return impl::make_from_tuple<T>(std::forward<Tuple>(t),
+                       std::make_index_sequence<std::tuple_size<std::remove_reference_t<Tuple>>::value>{});
+}
+#endif
+
+} // namespace mstd
+
+#endif // MSTD_TUPLE_