| |
| #ifndef BOOST_MPL_HAS_XXX_HPP_INCLUDED |
| #define BOOST_MPL_HAS_XXX_HPP_INCLUDED |
| |
| // Copyright Aleksey Gurtovoy 2002-2006 |
| // Copyright David Abrahams 2002-2003 |
| // |
| // Distributed under 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/mpl for documentation. |
| |
| // $Id: has_xxx.hpp 49273 2008-10-11 06:54:06Z agurtovoy $ |
| // $Date: 2008-10-11 02:54:06 -0400 (Sat, 11 Oct 2008) $ |
| // $Revision: 49273 $ |
| |
| #include <boost/mpl/bool.hpp> |
| #include <boost/mpl/aux_/type_wrapper.hpp> |
| #include <boost/mpl/aux_/yes_no.hpp> |
| #include <boost/mpl/aux_/config/has_xxx.hpp> |
| #include <boost/mpl/aux_/config/msvc_typename.hpp> |
| #include <boost/mpl/aux_/config/msvc.hpp> |
| #include <boost/mpl/aux_/config/static_constant.hpp> |
| #include <boost/mpl/aux_/config/workaround.hpp> |
| |
| #include <boost/preprocessor/cat.hpp> |
| |
| #if BOOST_WORKAROUND( __BORLANDC__, BOOST_TESTED_AT(0x590) ) |
| # include <boost/type_traits/is_class.hpp> |
| #endif |
| |
| #if !defined(BOOST_MPL_CFG_NO_HAS_XXX) |
| |
| # if BOOST_WORKAROUND(BOOST_MSVC, <= 1300) |
| |
| // agurt, 11/sep/02: MSVC-specific version (< 7.1), based on a USENET |
| // newsgroup's posting by John Madsen (comp.lang.c++.moderated, |
| // 1999-11-12 19:17:06 GMT); the code is _not_ standard-conforming, but |
| // it works way more reliably than the SFINAE-based implementation |
| |
| // Modified dwa 8/Oct/02 to handle reference types. |
| |
| # include <boost/mpl/if.hpp> |
| # include <boost/mpl/bool.hpp> |
| |
| namespace boost { namespace mpl { namespace aux { |
| |
| struct has_xxx_tag; |
| |
| #if BOOST_WORKAROUND(BOOST_MSVC, == 1300) |
| template< typename U > struct msvc_incomplete_array |
| { |
| typedef char (&type)[sizeof(U) + 1]; |
| }; |
| #endif |
| |
| template< typename T > |
| struct msvc_is_incomplete |
| { |
| // MSVC is capable of some kinds of SFINAE. If U is an incomplete |
| // type, it won't pick the second overload |
| static char tester(...); |
| |
| #if BOOST_WORKAROUND(BOOST_MSVC, == 1300) |
| template< typename U > |
| static typename msvc_incomplete_array<U>::type tester(type_wrapper<U>); |
| #else |
| template< typename U > |
| static char (& tester(type_wrapper<U>) )[sizeof(U)+1]; |
| #endif |
| |
| BOOST_STATIC_CONSTANT(bool, value = |
| sizeof(tester(type_wrapper<T>())) == 1 |
| ); |
| }; |
| |
| template<> |
| struct msvc_is_incomplete<int> |
| { |
| BOOST_STATIC_CONSTANT(bool, value = false); |
| }; |
| |
| }}} |
| |
| # define BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF_(trait, name, default_) \ |
| template< typename T, typename name = ::boost::mpl::aux::has_xxx_tag > \ |
| struct BOOST_PP_CAT(trait,_impl) : T \ |
| { \ |
| static boost::mpl::aux::no_tag \ |
| test(void(*)(::boost::mpl::aux::has_xxx_tag)); \ |
| \ |
| static boost::mpl::aux::yes_tag test(...); \ |
| \ |
| BOOST_STATIC_CONSTANT(bool, value = \ |
| sizeof(test(static_cast<void(*)(name)>(0))) \ |
| != sizeof(boost::mpl::aux::no_tag) \ |
| ); \ |
| typedef boost::mpl::bool_<value> type; \ |
| }; \ |
| \ |
| template< typename T, typename fallback_ = boost::mpl::bool_<default_> > \ |
| struct trait \ |
| : boost::mpl::if_c< \ |
| boost::mpl::aux::msvc_is_incomplete<T>::value \ |
| , boost::mpl::bool_<false> \ |
| , BOOST_PP_CAT(trait,_impl)<T> \ |
| >::type \ |
| { \ |
| }; \ |
| \ |
| BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, void) \ |
| BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, bool) \ |
| BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, char) \ |
| BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, signed char) \ |
| BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, unsigned char) \ |
| BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, signed short) \ |
| BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, unsigned short) \ |
| BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, signed int) \ |
| BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, unsigned int) \ |
| BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, signed long) \ |
| BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, unsigned long) \ |
| BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, float) \ |
| BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, double) \ |
| BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, long double) \ |
| /**/ |
| |
| # define BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, T) \ |
| template<> struct trait<T> \ |
| { \ |
| BOOST_STATIC_CONSTANT(bool, value = false); \ |
| typedef boost::mpl::bool_<false> type; \ |
| }; \ |
| /**/ |
| |
| #if !defined(BOOST_NO_INTRINSIC_WCHAR_T) |
| # define BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF(trait, name, unused) \ |
| BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF_(trait, name, unused) \ |
| BOOST_MPL_AUX_HAS_XXX_TRAIT_SPEC(trait, wchar_t) \ |
| /**/ |
| #else |
| # define BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF(trait, name, unused) \ |
| BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF_(trait, name, unused) \ |
| /**/ |
| #endif |
| |
| |
| // SFINAE-based implementations below are derived from a USENET newsgroup's |
| // posting by Rani Sharoni (comp.lang.c++.moderated, 2002-03-17 07:45:09 PST) |
| |
| # elif BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1400)) \ |
| || BOOST_WORKAROUND(__IBMCPP__, <= 700) |
| |
| // MSVC 7.1+ & VACPP |
| |
| // agurt, 15/jun/05: replace overload-based SFINAE implementation with SFINAE |
| // applied to partial specialization to fix some apparently random failures |
| // (thanks to Daniel Wallin for researching this!) |
| |
| # define BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF(trait, name, default_) \ |
| template< typename T > \ |
| struct BOOST_PP_CAT(trait, _msvc_sfinae_helper) \ |
| { \ |
| typedef void type; \ |
| };\ |
| \ |
| template< typename T, typename U = void > \ |
| struct BOOST_PP_CAT(trait,_impl_) \ |
| { \ |
| BOOST_STATIC_CONSTANT(bool, value = false); \ |
| typedef boost::mpl::bool_<value> type; \ |
| }; \ |
| \ |
| template< typename T > \ |
| struct BOOST_PP_CAT(trait,_impl_)< \ |
| T \ |
| , typename BOOST_PP_CAT(trait, _msvc_sfinae_helper)< typename T::name >::type \ |
| > \ |
| { \ |
| BOOST_STATIC_CONSTANT(bool, value = true); \ |
| typedef boost::mpl::bool_<value> type; \ |
| }; \ |
| \ |
| template< typename T, typename fallback_ = boost::mpl::bool_<default_> > \ |
| struct trait \ |
| : BOOST_PP_CAT(trait,_impl_)<T> \ |
| { \ |
| }; \ |
| /**/ |
| |
| # elif BOOST_WORKAROUND( __BORLANDC__, BOOST_TESTED_AT(0x590) ) |
| |
| # define BOOST_MPL_HAS_XXX_TRAIT_NAMED_BCB_DEF(trait, trait_tester, name, default_) \ |
| template< typename T, bool IS_CLASS > \ |
| struct trait_tester \ |
| { \ |
| BOOST_STATIC_CONSTANT( bool, value = false ); \ |
| }; \ |
| template< typename T > \ |
| struct trait_tester< T, true > \ |
| { \ |
| struct trait_tester_impl \ |
| { \ |
| template < class U > \ |
| static int resolve( boost::mpl::aux::type_wrapper<U> const volatile * \ |
| , boost::mpl::aux::type_wrapper<typename U::name >* = 0 ); \ |
| static char resolve( ... ); \ |
| }; \ |
| typedef boost::mpl::aux::type_wrapper<T> t_; \ |
| BOOST_STATIC_CONSTANT( bool, value = ( sizeof( trait_tester_impl::resolve( static_cast< t_ * >(0) ) ) == sizeof(int) ) ); \ |
| }; \ |
| template< typename T, typename fallback_ = boost::mpl::bool_<default_> > \ |
| struct trait \ |
| { \ |
| BOOST_STATIC_CONSTANT( bool, value = (trait_tester< T, boost::is_class< T >::value >::value) ); \ |
| typedef boost::mpl::bool_< trait< T, fallback_ >::value > type; \ |
| }; |
| |
| # define BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF(trait, name, default_) \ |
| BOOST_MPL_HAS_XXX_TRAIT_NAMED_BCB_DEF( trait \ |
| , BOOST_PP_CAT(trait,_tester) \ |
| , name \ |
| , default_ ) \ |
| /**/ |
| |
| # else // other SFINAE-capable compilers |
| |
| # define BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF(trait, name, default_) \ |
| template< typename T, typename fallback_ = boost::mpl::bool_<default_> > \ |
| struct trait \ |
| { \ |
| struct gcc_3_2_wknd \ |
| { \ |
| template< typename U > \ |
| static boost::mpl::aux::yes_tag test( \ |
| boost::mpl::aux::type_wrapper<U> const volatile* \ |
| , boost::mpl::aux::type_wrapper<BOOST_MSVC_TYPENAME U::name>* = 0 \ |
| ); \ |
| \ |
| static boost::mpl::aux::no_tag test(...); \ |
| }; \ |
| \ |
| typedef boost::mpl::aux::type_wrapper<T> t_; \ |
| BOOST_STATIC_CONSTANT(bool, value = \ |
| sizeof(gcc_3_2_wknd::test(static_cast<t_*>(0))) \ |
| == sizeof(boost::mpl::aux::yes_tag) \ |
| ); \ |
| typedef boost::mpl::bool_<value> type; \ |
| }; \ |
| /**/ |
| |
| # endif // BOOST_WORKAROUND(BOOST_MSVC, <= 1300) |
| |
| |
| #else // BOOST_MPL_CFG_NO_HAS_XXX |
| |
| // placeholder implementation |
| |
| # define BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF(trait, name, default_) \ |
| template< typename T, typename fallback_ = boost::mpl::bool_<default_> > \ |
| struct trait \ |
| { \ |
| BOOST_STATIC_CONSTANT(bool, value = fallback_::value); \ |
| typedef fallback_ type; \ |
| }; \ |
| /**/ |
| |
| #endif |
| |
| #define BOOST_MPL_HAS_XXX_TRAIT_DEF(name) \ |
| BOOST_MPL_HAS_XXX_TRAIT_NAMED_DEF(BOOST_PP_CAT(has_,name), name, false) \ |
| /**/ |
| |
| #endif // BOOST_MPL_HAS_XXX_HPP_INCLUDED |