Working version of strategy grouping

mapnik · Apr 17, 2015 · 8ad5648 · 8ad5648
1 parent 75ccfdf
commit 8ad5648
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Showing 2 changed files with 40 additions and 16 deletions.
diff --git a/include/mapnik/geometry_strategy.hpp b/include/mapnik/geometry_strategy.hpp
@@ -26,40 +26,64 @@
 namespace mapnik { 
 namespace geometry {
 
-template <typename Strategy, typename... Strategies>
+namespace helper
+{
+    template <std::size_t... Ts>
+    struct index {};
+
+    template <std::size_t N, std::size_t... Ts>
+    struct gen_seq : gen_seq<N - 1, N - 1, Ts...> {};
+
+    template <std::size_t... Ts>
+    struct gen_seq<0, Ts...> : index<Ts...> {};
+}
+
+template <typename... Strategies>
 struct strategy_group
 {
-    strategy_group(Strategy const& op, Strategies const& ... ops)
-        : ops_(op, ops ...) {}
+    strategy_group(Strategies const& ... ops)
+        : ops_(ops ...) {}
 
     template <typename P1, typename P2>
     inline bool apply(P1 const& p1, P2 & p2) const
     {
         bool status = true;
-        p2 = execute_first<0, P1, P2, Strategy, ...Strategies>(p1, status);
+        p2 = execute_start<P1,P2>(p1, status, ops_);
         return status;
     }
 
-    template <int c, typename P1, typename P2, typename T, typename ...Args>
-    inline P2 execute_first(P1 const& p, bool & status) 
+    template <typename P1, typename P2, typename... Args, std::size_t... Is>
+    inline P2 execute_start(P1 const & p1, bool & status, std::tuple<Args const&...> const& tup, helper::index<Is...>) const
+    {
+        return execute_first<P1,P2, Args...>(p1, status, std::get<Is>(tup)...);
+    }
+
+    template <typename P1, typename P2>
+    inline P2 execute_start(P1 const& p, bool & status, std::tuple<Strategies const& ...> const& tup) const
+    {
+        return execute_start<P1,P2, Strategies...>(p, status, tup, helper::gen_seq<sizeof...(Strategies)> {} );
+    }
+
+    template <typename P1, typename P2, typename T, typename ...Args>
+    inline P2 execute_first(P1 const& p, bool & status, T const& strat, Args const& ... args) const
     { 
-        return execute_next<c+1,P1,P2,...Args>(std::get<c>(ops_).template execute<P1,P2>(p, status), status);
+        return execute_next(strat.template execute<P1,P2>(p, status), status, args...);
     }
 
-    template <int c, typename P2, typename T, typename ...Args>
-    inline P2 execute_next(P2 const& p, bool & status)
+    template <typename P2, typename T, typename ...Args>
+    inline P2 execute_next(P2 const& p, bool & status, T const& strat, Args const& ... args) const
     {
-        return execute_next<c+1, P2, ...Args>(std::get<c>(ops_).template execute<P2,P2>(p, status), status);
+        return execute_next(strat.template execute<P2,P2>(p, status), status, args...);
     }
 
-    template <int c, typename P2, typename T>
-    inline P2 execute_next(P2 const& p, bool & status)
+    template <typename P2>
+    inline P2 execute_next(P2 const& p, bool & status) const
     {
-        return std::get<c>(ops_).template execute<P2,P2>(p, status);
+        return p;
     }
 
 private:
-    std::tuple<Strategy const&, Strategies const& ...> ops_;
+    std::tuple<Strategies const& ...> ops_;
 
 };
 

diff --git a/tests/cxx/geometry_strategy_test.cpp b/tests/cxx/geometry_strategy_test.cpp
@@ -40,15 +40,15 @@ SECTION("proj and view strategy") {
 
     }
     {
-        // Test that both work streamed together
+        // Test that both work grouped together
         using sg_type = strategy_group<mapnik::proj_strategy, mapnik::view_strategy<double> >;
         sg_type sg(ps, vs);
         point<double> p1(-97.553098,35.523105);
         point<double> r1(58.6287 , 100.945);
         geometry<double> p2 = transform<double>(p1, sg);
         REQUIRE(p2.is<point<double> >());
         point<double> p3 = mapnik::util::get<point<double> >(p2);
-        std::cout << p3.x << " , " << p3.y << std::endl;
+        //std::cout << p3.x << " , " << p3.y << std::endl;
         assert_g_equal(r1, p3);
     }