// (C) Copyright Steve Cleary, Beman Dawes, Howard Hinnant & John Maddock 2000. // Use, modification and distribution are subject to the Boost Software License, // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at // http://www.boost.org/LICENSE_1_0.txt). // // See http://www.boost.org/libs/utility for most recent version including documentation. // // Crippled version for crippled compilers: // see libs/utility/call_traits.htm // /* Release notes: 01st October 2000: Fixed call_traits on VC6, using "poor man's partial specialisation", using ideas taken from "Generative programming" by Krzysztof Czarnecki & Ulrich Eisenecker. */ #ifndef BOOST_OB_CALL_TRAITS_HPP #define BOOST_OB_CALL_TRAITS_HPP #ifndef BOOST_CONFIG_HPP #include <boost/config.hpp> #endif #ifndef BOOST_ARITHMETIC_TYPE_TRAITS_HPP #include <boost/type_traits/arithmetic_traits.hpp> #endif #ifndef BOOST_COMPOSITE_TYPE_TRAITS_HPP #include <boost/type_traits/composite_traits.hpp> #endif namespace boost{ #ifdef BOOST_MSVC6_MEMBER_TEMPLATES // // use member templates to emulate // partial specialisation: // namespace detail{ template <class T> struct standard_call_traits { typedef T value_type; typedef T& reference; typedef const T& const_reference; typedef const T& param_type; }; template <class T> struct simple_call_traits { typedef T value_type; typedef T& reference; typedef const T& const_reference; typedef const T param_type; }; template <class T> struct reference_call_traits { typedef T value_type; typedef T reference; typedef T const_reference; typedef T param_type; }; template <bool pointer, bool arithmetic, bool reference> struct call_traits_chooser { template <class T> struct rebind { typedef standard_call_traits<T> type; }; }; template <> struct call_traits_chooser<true, false, false> { template <class T> struct rebind { typedef simple_call_traits<T> type; }; }; template <> struct call_traits_chooser<false, false, true> { template <class T> struct rebind { typedef reference_call_traits<T> type; }; }; template <bool size_is_small> struct call_traits_sizeof_chooser2 { template <class T> struct small_rebind { typedef simple_call_traits<T> small_type; }; }; template<> struct call_traits_sizeof_chooser2<false> { template <class T> struct small_rebind { typedef standard_call_traits<T> small_type; }; }; template <> struct call_traits_chooser<false, true, false> { template <class T> struct rebind { enum { sizeof_choice = (sizeof(T) <= sizeof(void*)) }; typedef call_traits_sizeof_chooser2<(sizeof(T) <= sizeof(void*))> chooser; typedef typename chooser::template small_rebind<T> bound_type; typedef typename bound_type::small_type type; }; }; } // namespace detail template <typename T> struct call_traits { private: typedef detail::call_traits_chooser< ::boost::is_pointer<T>::value, ::boost::is_arithmetic<T>::value, ::boost::is_reference<T>::value > chooser; typedef typename chooser::template rebind<T> bound_type; typedef typename bound_type::type call_traits_type; public: typedef typename call_traits_type::value_type value_type; typedef typename call_traits_type::reference reference; typedef typename call_traits_type::const_reference const_reference; typedef typename call_traits_type::param_type param_type; }; #else // // sorry call_traits is completely non-functional // blame your broken compiler: // template <typename T> struct call_traits { typedef T value_type; typedef T& reference; typedef const T& const_reference; typedef const T& param_type; }; #endif // member templates } #endif // BOOST_OB_CALL_TRAITS_HPP