feat add rxcpp

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

@@ -0,0 +1,142 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved. See License.txt in the project root for license information.
+
+#pragma once
+
+/*! \file rx-distinct_until_changed.hpp
+
+    \brief For each item from this observable, filter out consequentially repeated values and emit only changes from the new observable that is returned.
+
+    \tparam BinaryPredicate (optional) the type of the value comparing function. The signature should be equivalent to the following: bool pred(const T1& a, const T2& b);
+
+    \param pred (optional) the function that implements comparison of two values.
+
+    \return  Observable that emits those items from the source observable that are distinct from their immediate predecessors.
+
+    \sample
+    \snippet distinct_until_changed.cpp distinct_until_changed sample
+    \snippet output.txt distinct_until_changed sample
+*/
+
+#if !defined(RXCPP_OPERATORS_RX_DISTINCT_UNTIL_CHANGED_HPP)
+#define RXCPP_OPERATORS_RX_DISTINCT_UNTIL_CHANGED_HPP
+
+#include "../rx-includes.hpp"
+
+namespace rxcpp {
+
+namespace operators {
+
+namespace detail {
+
+template<class... AN>
+struct distinct_until_changed_invalid_arguments {};
+
+template<class... AN>
+struct distinct_until_changed_invalid : public rxo::operator_base<distinct_until_changed_invalid_arguments<AN...>> {
+    using type = observable<distinct_until_changed_invalid_arguments<AN...>, distinct_until_changed_invalid<AN...>>;
+};
+template<class... AN>
+using distinct_until_changed_invalid_t = typename distinct_until_changed_invalid<AN...>::type;
+
+template<class T, class BinaryPredicate>
+struct distinct_until_changed
+{
+    typedef rxu::decay_t<T> source_value_type;
+    typedef rxu::decay_t<BinaryPredicate> predicate_type;
+
+    predicate_type pred;
+
+    distinct_until_changed(predicate_type p)
+    : pred(std::move(p))
+    {
+    }
+
+    template<class Subscriber>
+    struct distinct_until_changed_observer
+    {
+        typedef distinct_until_changed_observer<Subscriber> this_type;
+        typedef source_value_type value_type;
+        typedef rxu::decay_t<Subscriber> dest_type;
+        typedef observer<value_type, this_type> observer_type;
+
+        dest_type dest;
+        predicate_type pred;
+        mutable rxu::detail::maybe<source_value_type> remembered;
+
+        distinct_until_changed_observer(dest_type d, predicate_type pred)
+            : dest(std::move(d))
+            , pred(std::move(pred))
+        {
+        }
+        void on_next(source_value_type v) const {
+            if (remembered.empty() || !pred(v, remembered.get())) {
+                remembered.reset(v);
+                dest.on_next(v);
+            }
+        }
+        void on_error(rxu::error_ptr e) const {
+            dest.on_error(e);
+        }
+        void on_completed() const {
+            dest.on_completed();
+        }
+
+        static subscriber<value_type, observer_type> make(dest_type d, predicate_type p) {
+            return make_subscriber<value_type>(d, this_type(d, std::move(p)));
+        }
+    };
+
+    template<class Subscriber>
+    auto operator()(Subscriber dest) const
+        -> decltype(distinct_until_changed_observer<Subscriber>::make(std::move(dest), pred)) {
+        return      distinct_until_changed_observer<Subscriber>::make(std::move(dest), pred);
+    }
+};
+
+}
+
+/*! @copydoc rx-distinct_until_changed.hpp
+*/
+template<class... AN>
+auto distinct_until_changed(AN&&... an)
+    ->      operator_factory<distinct_until_changed_tag, AN...> {
+     return operator_factory<distinct_until_changed_tag, AN...>(std::make_tuple(std::forward<AN>(an)...));
+}
+
+}
+
+template<>
+struct member_overload<distinct_until_changed_tag>
+{
+    template<class Observable,
+            class SourceValue = rxu::value_type_t<Observable>,
+            class Enabled = rxu::enable_if_all_true_type_t<
+                is_observable<Observable>>,
+            class DistinctUntilChanged = rxo::detail::distinct_until_changed<SourceValue, rxu::equal_to<>>>
+    static auto member(Observable&& o)
+    -> decltype(o.template lift<SourceValue>(DistinctUntilChanged(rxu::equal_to<>()))) {
+        return  o.template lift<SourceValue>(DistinctUntilChanged(rxu::equal_to<>()));
+    }
+
+    template<class Observable,
+            class BinaryPredicate,
+            class SourceValue = rxu::value_type_t<Observable>,
+            class Enabled = rxu::enable_if_all_true_type_t<
+            is_observable<Observable>>,
+            class DistinctUntilChanged = rxo::detail::distinct_until_changed<SourceValue, BinaryPredicate>>
+    static auto member(Observable&& o, BinaryPredicate&& pred)
+    -> decltype(o.template lift<SourceValue>(DistinctUntilChanged(std::forward<BinaryPredicate>(pred)))) {
+        return  o.template lift<SourceValue>(DistinctUntilChanged(std::forward<BinaryPredicate>(pred)));
+    }
+
+    template<class... AN>
+    static operators::detail::distinct_until_changed_invalid_t<AN...> member(AN...) {
+        std::terminate();
+        return {};
+        static_assert(sizeof...(AN) == 10000, "distinct_until_changed takes (optional BinaryPredicate)");
+    }
+};
+
+}
+
+#endif