ceph/src/boost/boost/type_index/runtime_cast/detail/runtime_cast_impl.hpp

   1 //
   2 // Copyright (c) Chris Glover, 2016.
   3 //
   4 //
   5 // Distributed under the Boost Software License, Version 1.0. (See accompanying
   6 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   7 //
   8
   9 #ifndef BOOST_TYPE_INDEX_RUNTIME_CAST_DETAIL_RUNTIME_CAST_IMPL_HPP
  10 #define BOOST_TYPE_INDEX_RUNTIME_CAST_DETAIL_RUNTIME_CAST_IMPL_HPP
  11
  12 /// \file runtime_cast_impl.hpp
  13 /// \brief Contains the overload of boost::typeindex::runtime_cast for
  14 /// pointer types.
  15 ///
  16 /// boost::typeindex::runtime_cast can be used to emulate dynamic_cast
  17 /// functionality on platorms that don't provide it or should the user
  18 /// desire opt in functionality instead of enabling it system wide.
  19
  20 #include <boost/type_index.hpp>
  21 #include <boost/type_traits/integral_constant.hpp>
  22
  23 #ifdef BOOST_HAS_PRAGMA_ONCE
  24 # pragma once
  25 #endif
  26
  27 namespace boost { namespace typeindex {
  28
  29 namespace detail {
  30
  31 template<typename T, typename U>
  32 T* runtime_cast_impl(U* u, boost::true_type) BOOST_NOEXCEPT {
  33     return u;
  34 }
  35
  36 template<typename T, typename U>
  37 T const* runtime_cast_impl(U const* u, boost::true_type) BOOST_NOEXCEPT {
  38     return u;
  39 }
  40
  41 template<typename T, typename U>
  42 T* runtime_cast_impl(U* u, boost::false_type) BOOST_NOEXCEPT {
  43     return const_cast<T*>(static_cast<T const*>(
  44         u->boost_type_index_find_instance_(boost::typeindex::type_id<T>())
  45     ));
  46 }
  47
  48 template<typename T, typename U>
  49 T const* runtime_cast_impl(U const* u, boost::false_type) BOOST_NOEXCEPT {
  50     return static_cast<T const*>(u->boost_type_index_find_instance_(boost::typeindex::type_id<T>()));
  51 }
  52
  53 } // namespace detail
  54
  55 }} // namespace boost::typeindex
  56
  57 #endif // BOOST_TYPE_INDEX_RUNTIME_CAST_DETAIL_RUNTIME_CAST_IMPL_HPP