107 lines
3.0 KiB
Plaintext
107 lines
3.0 KiB
Plaintext
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// Copyright David Abrahams 2002.
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// Distributed under the Boost Software License, Version 1.0. (See
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// accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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#ifndef CAST_DWA200269_HPP
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# define CAST_DWA200269_HPP
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# include <boost/python/detail/prefix.hpp>
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# include <boost/type_traits/same_traits.hpp>
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# include <boost/type_traits/cv_traits.hpp>
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# include <boost/type.hpp>
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# include <boost/python/base_type_traits.hpp>
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# include <boost/python/detail/convertible.hpp>
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namespace boost { namespace python {
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namespace detail
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{
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template <class Source, class Target> inline Target* upcast_impl(Source*, Target*);
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template <class Source, class Target>
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inline Target* upcast(Source* p, yes_convertible, no_convertible, Target*)
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{
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return p;
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}
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template <class Source, class Target>
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inline Target* upcast(Source* p, no_convertible, no_convertible, Target*)
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{
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typedef typename base_type_traits<Source>::type base;
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return detail::upcast_impl((base*)p, (Target*)0);
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}
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template <bool is_same = true>
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struct upcaster
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{
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template <class T>
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static inline T* execute(T* x, T*) { return x; }
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};
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template <>
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struct upcaster<false>
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{
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template <class Source, class Target>
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static inline Target* execute(Source* x, Target*)
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{
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return detail::upcast(
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x, detail::convertible<Target*>::check(x)
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, detail::convertible<Source*>::check((Target*)0)
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, (Target*)0);
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}
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};
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template <class Target, class Source>
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inline Target* downcast(Source* p, yes_convertible)
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{
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return static_cast<Target*>(p);
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}
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template <class Target, class Source>
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inline Target* downcast(Source* p, no_convertible, boost::type<Target>* = 0)
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{
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typedef typename base_type_traits<Source>::type base;
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return (Target*)detail::downcast<base>(p, convertible<Source*>::check((base*)0));
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}
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template <class T>
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inline void assert_castable(boost::type<T>* = 0)
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{
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typedef char must_be_a_complete_type[sizeof(T)] BOOST_ATTRIBUTE_UNUSED;
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}
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template <class Source, class Target>
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inline Target* upcast_impl(Source* x, Target*)
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{
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typedef typename add_cv<Source>::type src_t;
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typedef typename add_cv<Target>::type target_t;
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bool const same = is_same<src_t,target_t>::value;
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return detail::upcaster<same>::execute(x, (Target*)0);
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}
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}
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template <class Target, class Source>
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inline Target* upcast(Source* x, Target* = 0)
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{
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detail::assert_castable<Source>();
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detail::assert_castable<Target>();
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return detail::upcast_impl(x, (Target*)0);
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}
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template <class Target, class Source>
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inline Target* downcast(Source* x, Target* = 0)
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{
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detail::assert_castable<Source>();
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detail::assert_castable<Target>();
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return detail::downcast<Target>(x, detail::convertible<Source*>::check((Target*)0));
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}
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}} // namespace boost::python
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#endif // CAST_DWA200269_HPP
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