Merge branch 'feature/switch_cases' into 'master'

add hybrid utility SwitchCases for dynamic and static dispatching

See merge request amdis/amdis-core!51

src/amdis/common/CMakeLists.txt

@@ -26,6 +26,7 @@ install(FILES
     Resize.hpp
     StaticSize.hpp
     String.hpp
+    SwitchCases.hpp
     Tags.hpp
     Transposed.hpp
     TupleUtility.hpp

src/amdis/common/SwitchCases.hpp

+#pragma once
+
+#include <cassert>
+
+#include <dune/common/hybridutilities.hh>
+#include <dune/common/rangeutilities.hh>
+
+namespace AMDiS
+{
+  // static switching. Iterates over all possible values
+  template <class T, T to, T from, class Value, class Then, class Else>
+  constexpr decltype(auto) switchCases(const Dune::StaticIntegralRange<T,to,from>& cases, const Value& value,
+                                       Then&& thenBranch, Else&& elseBranch)
+  {
+    using integer_sequence = typename Dune::StaticIntegralRange<T,to,from>::integer_sequence;
+    return Dune::Hybrid::switchCases(integer_sequence{}, value, FWD(thenBranch), FWD(elseBranch));
+  }
+
+  // dynamic switching. Calls the `thenBranch` or `elseBranch` directly
+  template <class T, class Value, class Then, class Else>
+  constexpr decltype(auto) switchCases(const Dune::IntegralRange<T>& cases, const Value& value,
+                                       Then&& thenBranch, Else&& elseBranch)
+  {
+    if (value >= cases[0] && value <= cases[cases.size()-1])
+      return thenBranch(value);
+    else
+      return elseBranch(value);
+  }
+
+  // static switching. Iterates over all possible values
+  template<class T, T to, T from, class Value, class Then>
+  constexpr void switchCases(const Dune::StaticIntegralRange<T,to,from>& cases, const Value& value, Then&& thenBranch)
+  {
+    using integer_sequence = typename Dune::StaticIntegralRange<T,to,from>::integer_sequence;
+    Dune::Hybrid::switchCases(integer_sequence{}, value, FWD(thenBranch));
+  }
+
+  // dynamic switching. Calls the `thenBranch` directly
+  template<class T, class Value, class Then>
+  constexpr void switchCases(const Dune::IntegralRange<T>& cases, const Value& value, Then&& thenBranch)
+  {
+    assert(value >= cases[0] && value <= cases[cases.size()-1]);
+    thenBranch(value);
+  }
+
+} // end namespace AMDiS

test/CMakeLists.txt

@@ -67,6 +67,9 @@ dune_add_test(SOURCES RangeTypeTest.cpp
 dune_add_test(SOURCES ResizeTest.cpp
   LINK_LIBRARIES amdis)
 
+dune_add_test(SOURCES SwitchCasesTest.cpp
+  LINK_LIBRARIES amdis)
+
 dune_add_test(SOURCES StringTest.cpp
   LINK_LIBRARIES amdis)
 

test/SwitchCasesTest.cpp

+#include <amdis/AMDiS.hpp>
+#include <amdis/common/SwitchCases.hpp>
+
+using namespace AMDiS;
+
+template <std::size_t i>
+struct Foo
+{
+  void foo() {}
+};
+
+struct Bar
+{
+  void bar(std::size_t i) {}
+};
+
+template <std::size_t max_i>
+void call_foo(std::size_t i)
+{
+  switchCases(Dune::range(index_t<max_i>{}), i, [](auto _i) { Foo<_i.value>{}.foo(); });
+}
+
+void call_bar(std::size_t i, std::size_t max_i)
+{
+  switchCases(Dune::range(max_i), i, [](auto _i) { Bar{}.bar(_i); });
+}
+
+int main(int argc, char** argv)
+{
+  call_foo<1>(0);
+  call_foo<2>(1);
+  call_foo<3>(2);
+  call_foo<10>(7);
+
+  call_bar(0, 1);
+  call_bar(1, 2);
+  call_bar(2, 3);
+  call_bar(7, 10);
+  return 0;
+}