feat add rxcpp

3party/rxcpp/operators/rx-pairwise.hpp

@@ -0,0 +1,126 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved. See License.txt in the project root for license information.
+
+#pragma once
+
+/*! \file rx-pairwise.hpp
+
+    \brief Take values pairwise from this observable.
+
+    \return Observable that emits tuples of two the most recent items emitted by the source observable.
+
+    \sample
+    \snippet pairwise.cpp pairwise sample
+    \snippet output.txt pairwise sample
+
+    If the source observable emits less than two items, no pairs are emitted  by the source observable:
+    \snippet pairwise.cpp pairwise short sample
+    \snippet output.txt pairwise short sample
+*/
+
+#if !defined(RXCPP_OPERATORS_RX_PAIRWISE_HPP)
+#define RXCPP_OPERATORS_RX_PAIRWISE_HPP
+
+#include "../rx-includes.hpp"
+
+namespace rxcpp {
+
+namespace operators {
+
+namespace detail {
+
+template<class... AN>
+struct pairwise_invalid_arguments {};
+
+template<class... AN>
+struct pairwise_invalid : public rxo::operator_base<pairwise_invalid_arguments<AN...>> {
+    using type = observable<pairwise_invalid_arguments<AN...>, pairwise_invalid<AN...>>;
+};
+template<class... AN>
+using pairwise_invalid_t = typename pairwise_invalid<AN...>::type;
+
+template<class T>
+struct pairwise
+{
+    typedef rxu::decay_t<T> source_value_type;
+    typedef std::tuple<source_value_type, source_value_type> value_type;
+
+    template<class Subscriber>
+    struct pairwise_observer
+    {
+        typedef pairwise_observer<Subscriber> this_type;
+        typedef std::tuple<source_value_type, source_value_type> value_type;
+        typedef rxu::decay_t<Subscriber> dest_type;
+        typedef observer<T, this_type> observer_type;
+        dest_type dest;
+        mutable rxu::detail::maybe<source_value_type> remembered;
+
+        pairwise_observer(dest_type d)
+            : dest(std::move(d))
+        {
+        }
+        void on_next(source_value_type v) const {
+            if (remembered.empty()) {
+                remembered.reset(v);
+                return;
+            }
+
+            dest.on_next(std::make_tuple(remembered.get(), v));
+            remembered.reset(v);
+        }
+        void on_error(rxu::error_ptr e) const {
+            dest.on_error(e);
+        }
+        void on_completed() const {
+            dest.on_completed();
+        }
+
+        static subscriber<T, observer_type> make(dest_type d) {
+            auto cs = d.get_subscription();
+            return make_subscriber<T>(std::move(cs), observer_type(this_type(std::move(d))));
+        }
+    };
+
+    template<class Subscriber>
+    auto operator()(Subscriber dest) const
+        -> decltype(pairwise_observer<Subscriber>::make(std::move(dest))) {
+        return      pairwise_observer<Subscriber>::make(std::move(dest));
+    }
+};
+
+}
+
+/*! @copydoc rx-pairwise.hpp
+*/
+template<class... AN>
+auto pairwise(AN&&... an)
+    ->     operator_factory<pairwise_tag, AN...> {
+    return operator_factory<pairwise_tag, AN...>(std::make_tuple(std::forward<AN>(an)...));
+}
+
+}
+
+template<>
+struct member_overload<pairwise_tag>
+{
+    template<class Observable,
+        class Enabled = rxu::enable_if_all_true_type_t<
+            is_observable<Observable>>,
+        class SourceValue = rxu::value_type_t<Observable>,
+        class Pairwise = rxo::detail::pairwise<SourceValue>,
+        class Value = rxu::value_type_t<Pairwise>>
+    static auto member(Observable&& o)
+    -> decltype(o.template lift<Value>(Pairwise())) {
+        return  o.template lift<Value>(Pairwise());
+    }
+
+    template<class... AN>
+    static operators::detail::pairwise_invalid_t<AN...> member(AN...) {
+        std::terminate();
+        return {};
+        static_assert(sizeof...(AN) == 10000, "pairwise takes no arguments");
+    }
+};
+
+}
+
+#endif