ISAAC-V2.0: INITIAL COMMIT

include/isaac/tools/functional.hpp

@@ -0,0 +1,84 @@
+/*
+ * Copyright (c) 2015, PHILIPPE TILLET. All rights reserved.
+ *
+ * This file is part of ISAAC.
+ *
+ * ISAAC is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301  USA
+ */
+
+#ifndef ISAAC_CPP_FUNCTIONAL_HPP
+#define ISAAC_CPP_FUNCTIONAL_HPP
+
+#include <type_traits>
+#include <tuple>
+
+namespace isaac
+{
+namespace cpp
+{
+
+template <typename T>
+struct function_traits
+    : public function_traits<decltype(&T::operator())>
+{};
+// For generic types, directly use the result of the signature of its 'operator()'
+
+template <typename ClassType, typename ReturnType, typename... Args>
+struct function_traits<ReturnType(ClassType::*)(Args...) const>
+// we specialize for pointers to member function
+{
+  enum { arity = sizeof...(Args) };
+  // arity is the number of arguments.
+
+  typedef ReturnType result_type;
+
+  template <size_t i>
+  struct arg
+  {
+    typedef typename std::tuple_element<i, std::tuple<Args...>>::type type;
+    // the i-th argument is equivalent to the i-th tuple element of a tuple
+    // composed of those arguments.
+  };
+};
+
+
+template<class U, class FN, class V>
+V forward_dyncast(U const & x, FN const & fn, V const &backup)
+{
+  typedef typename function_traits<FN>::template arg<0>::type RT;
+  typedef typename std::remove_reference<RT>::type T;
+  if(T const * p = dynamic_cast<T const *>(&x))
+    return fn(*p);
+  return backup;
+}
+
+template<class U, class FN>
+void forward_dyncast(U const & x, FN const & fn)
+{
+  typedef typename function_traits<FN>::template arg<0>::type RT;
+  typedef typename std::remove_reference<RT>::type T;
+  if(T const * p = dynamic_cast<T const *>(&x))
+    fn(*p);
+}
+
+template<class U, class FN>
+bool compare_if_same(U const & base, FN const & f)
+{ return cpp::forward_dyncast(base, f, false); }
+
+}
+}
+
+#endif