decay.hpp 1.3 KB

1234567891011121314151617181920212223242526272829303132333435363738394041424344
  1. // (C) Copyright John Maddock & Thorsten Ottosen 2005.
  2. // Use, modification and distribution are subject to the Boost Software License,
  3. // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
  4. // http://www.boost.org/LICENSE_1_0.txt).
  5. //
  6. // See http://www.boost.org/libs/type_traits for most recent version including documentation.
  7. #ifndef BOOST_TT_DECAY_HPP_INCLUDED
  8. #define BOOST_TT_DECAY_HPP_INCLUDED
  9. #include <boost/type_traits/config.hpp>
  10. #include <boost/type_traits/is_array.hpp>
  11. #include <boost/type_traits/is_function.hpp>
  12. #include <boost/type_traits/remove_bounds.hpp>
  13. #include <boost/type_traits/add_pointer.hpp>
  14. #include <boost/type_traits/remove_reference.hpp>
  15. #include <boost/mpl/eval_if.hpp>
  16. #include <boost/mpl/identity.hpp>
  17. namespace boost
  18. {
  19. template< class T >
  20. struct decay
  21. {
  22. private:
  23. typedef BOOST_DEDUCED_TYPENAME remove_reference<T>::type Ty;
  24. public:
  25. typedef BOOST_DEDUCED_TYPENAME mpl::eval_if<
  26. is_array<Ty>,
  27. mpl::identity<BOOST_DEDUCED_TYPENAME remove_bounds<Ty>::type*>,
  28. BOOST_DEDUCED_TYPENAME mpl::eval_if<
  29. is_function<Ty>,
  30. add_pointer<Ty>,
  31. mpl::identity<Ty>
  32. >
  33. >::type type;
  34. };
  35. } // namespace boost
  36. #endif // BOOST_TT_DECAY_HPP_INCLUDED