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Diffstat (limited to 'libcutl/cutl/details/boost/type_traits/is_base_and_derived.hpp')
| -rw-r--r-- | libcutl/cutl/details/boost/type_traits/is_base_and_derived.hpp | 254 |
1 files changed, 254 insertions, 0 deletions
diff --git a/libcutl/cutl/details/boost/type_traits/is_base_and_derived.hpp b/libcutl/cutl/details/boost/type_traits/is_base_and_derived.hpp new file mode 100644 index 0000000..2268820 --- /dev/null +++ b/libcutl/cutl/details/boost/type_traits/is_base_and_derived.hpp @@ -0,0 +1,254 @@ + +// (C) Copyright Rani Sharoni 2003. +// 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/type_traits for most recent version including documentation. + +#ifndef BOOST_TT_IS_BASE_AND_DERIVED_HPP_INCLUDED +#define BOOST_TT_IS_BASE_AND_DERIVED_HPP_INCLUDED + +#include <cutl/details/boost/type_traits/intrinsics.hpp> +#ifndef BOOST_IS_BASE_OF +#include <cutl/details/boost/type_traits/is_class.hpp> +#include <cutl/details/boost/type_traits/is_same.hpp> +#include <cutl/details/boost/type_traits/is_convertible.hpp> +#include <cutl/details/boost/type_traits/detail/ice_and.hpp> +#include <cutl/details/boost/config.hpp> +#include <cutl/details/boost/static_assert.hpp> +#endif +#include <cutl/details/boost/type_traits/remove_cv.hpp> + +// should be the last #include +#include <cutl/details/boost/type_traits/detail/bool_trait_def.hpp> + +namespace cutl_details_boost { + +namespace detail { + +#ifndef BOOST_IS_BASE_OF +#if !BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x581)) \ + && !BOOST_WORKAROUND(__SUNPRO_CC , <= 0x540) \ + && !BOOST_WORKAROUND(__EDG_VERSION__, <= 243) \ + && !BOOST_WORKAROUND(__DMC__, BOOST_TESTED_AT(0x840)) + + // The EDG version number is a lower estimate. + // It is not currently known which EDG version + // exactly fixes the problem. + +/************************************************************************* + +This version detects ambiguous base classes and private base classes +correctly, and was devised by Rani Sharoni. + +Explanation by Terje Slettebo and Rani Sharoni. + +Let's take the multiple base class below as an example, and the following +will also show why there's not a problem with private or ambiguous base +class: + +struct B {}; +struct B1 : B {}; +struct B2 : B {}; +struct D : private B1, private B2 {}; + +is_base_and_derived<B, D>::value; + +First, some terminology: + +SC - Standard conversion +UDC - User-defined conversion + +A user-defined conversion sequence consists of an SC, followed by an UDC, +followed by another SC. Either SC may be the identity conversion. + +When passing the default-constructed Host object to the overloaded check_sig() +functions (initialization 8.5/14/4/3), we have several viable implicit +conversion sequences: + +For "static no_type check_sig(B const volatile *, int)" we have the conversion +sequences: + +C -> C const (SC - Qualification Adjustment) -> B const volatile* (UDC) +C -> D const volatile* (UDC) -> B1 const volatile* / B2 const volatile* -> + B const volatile* (SC - Conversion) + +For "static yes_type check_sig(D const volatile *, T)" we have the conversion +sequence: + +C -> D const volatile* (UDC) + +According to 13.3.3.1/4, in context of user-defined conversion only the +standard conversion sequence is considered when selecting the best viable +function, so it only considers up to the user-defined conversion. For the +first function this means choosing between C -> C const and C -> C, and it +chooses the latter, because it's a proper subset (13.3.3.2/3/2) of the +former. Therefore, we have: + +C -> D const volatile* (UDC) -> B1 const volatile* / B2 const volatile* -> + B const volatile* (SC - Conversion) +C -> D const volatile* (UDC) + +Here, the principle of the "shortest subsequence" applies again, and it +chooses C -> D const volatile*. This shows that it doesn't even need to +consider the multiple paths to B, or accessibility, as that possibility is +eliminated before it could possibly cause ambiguity or access violation. + +If D is not derived from B, it has to choose between C -> C const -> B const +volatile* for the first function, and C -> D const volatile* for the second +function, which are just as good (both requires a UDC, 13.3.3.2), had it not +been for the fact that "static no_type check_sig(B const volatile *, int)" is +not templated, which makes C -> C const -> B const volatile* the best choice +(13.3.3/1/4), resulting in "no". + +Also, if Host::operator B const volatile* hadn't been const, the two +conversion sequences for "static no_type check_sig(B const volatile *, int)", in +the case where D is derived from B, would have been ambiguous. + +See also +http://groups.google.com/groups?selm=df893da6.0301280859.522081f7%40posting. +google.com and links therein. + +*************************************************************************/ + +template <typename B, typename D> +struct bd_helper +{ + // + // This VC7.1 specific workaround stops the compiler from generating + // an internal compiler error when compiling with /vmg (thanks to + // Aleksey Gurtovoy for figuring out the workaround). + // +#if !BOOST_WORKAROUND(BOOST_MSVC, == 1310) + template <typename T> + static type_traits::yes_type check_sig(D const volatile *, T); + static type_traits::no_type check_sig(B const volatile *, int); +#else + static type_traits::yes_type check_sig(D const volatile *, long); + static type_traits::no_type check_sig(B const volatile * const&, int); +#endif +}; + +template<typename B, typename D> +struct is_base_and_derived_impl2 +{ +#if BOOST_WORKAROUND(BOOST_MSVC_FULL_VER, >= 140050000) +#pragma warning(push) +#pragma warning(disable:6334) +#endif + // + // May silently do the wrong thing with incomplete types + // unless we trap them here: + // + BOOST_STATIC_ASSERT(sizeof(B) != 0); + BOOST_STATIC_ASSERT(sizeof(D) != 0); + + struct Host + { +#if !BOOST_WORKAROUND(BOOST_MSVC, == 1310) + operator B const volatile *() const; +#else + operator B const volatile * const&() const; +#endif + operator D const volatile *(); + }; + + BOOST_STATIC_CONSTANT(bool, value = + sizeof(bd_helper<B,D>::check_sig(Host(), 0)) == sizeof(type_traits::yes_type)); +#if BOOST_WORKAROUND(BOOST_MSVC_FULL_VER, >= 140050000) +#pragma warning(pop) +#endif +}; + +#else + +// +// broken version: +// +template<typename B, typename D> +struct is_base_and_derived_impl2 +{ + BOOST_STATIC_CONSTANT(bool, value = + (::cutl_details_boost::is_convertible<D*,B*>::value)); +}; + +#define BOOST_BROKEN_IS_BASE_AND_DERIVED + +#endif + +template <typename B, typename D> +struct is_base_and_derived_impl3 +{ + BOOST_STATIC_CONSTANT(bool, value = false); +}; + +template <bool ic1, bool ic2, bool iss> +struct is_base_and_derived_select +{ + template <class T, class U> + struct rebind + { + typedef is_base_and_derived_impl3<T,U> type; + }; +}; + +template <> +struct is_base_and_derived_select<true,true,false> +{ + template <class T, class U> + struct rebind + { + typedef is_base_and_derived_impl2<T,U> type; + }; +}; + +template <typename B, typename D> +struct is_base_and_derived_impl +{ + typedef typename remove_cv<B>::type ncvB; + typedef typename remove_cv<D>::type ncvD; + + typedef is_base_and_derived_select< + ::cutl_details_boost::is_class<B>::value, + ::cutl_details_boost::is_class<D>::value, + ::cutl_details_boost::is_same<ncvB,ncvD>::value> selector; + typedef typename selector::template rebind<ncvB,ncvD> binder; + typedef typename binder::type bound_type; + + BOOST_STATIC_CONSTANT(bool, value = bound_type::value); +}; +#else +template <typename B, typename D> +struct is_base_and_derived_impl +{ + typedef typename remove_cv<B>::type ncvB; + typedef typename remove_cv<D>::type ncvD; + + BOOST_STATIC_CONSTANT(bool, value = (BOOST_IS_BASE_OF(B,D) && ! ::cutl_details_boost::is_same<ncvB,ncvD>::value)); +}; +#endif +} // namespace detail + +BOOST_TT_AUX_BOOL_TRAIT_DEF2( + is_base_and_derived + , Base + , Derived + , (::cutl_details_boost::detail::is_base_and_derived_impl<Base,Derived>::value) + ) + +#ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION +BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC2_2(typename Base,typename Derived,is_base_and_derived,Base&,Derived,false) +BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC2_2(typename Base,typename Derived,is_base_and_derived,Base,Derived&,false) +BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC2_2(typename Base,typename Derived,is_base_and_derived,Base&,Derived&,false) +#endif + +#if BOOST_WORKAROUND(__CODEGEARC__, BOOST_TESTED_AT(0x610)) +BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC2_1(typename Base,is_base_and_derived,Base,Base,false) +#endif + +} // namespace cutl_details_boost + +#include <cutl/details/boost/type_traits/detail/bool_trait_undef.hpp> + +#endif // BOOST_TT_IS_BASE_AND_DERIVED_HPP_INCLUDED |