62 lines
2.3 KiB
C++
62 lines
2.3 KiB
C++
// Copyright (c) 2009-2016 Vladimir Batov.
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// Use, modification and distribution are subject to the Boost Software License,
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// Version 1.0. See http://www.boost.org/LICENSE_1_0.txt.
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#ifndef BOOST_CONVERT_IS_FUNCTION_HPP
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#define BOOST_CONVERT_IS_FUNCTION_HPP
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#include <boost/convert/detail/forward.hpp>
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#include <boost/convert/detail/has_member.hpp>
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#include <boost/utility/enable_if.hpp>
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#include <boost/type_traits.hpp>
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#include <boost/function_types/is_function_pointer.hpp>
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#include <boost/function_types/function_arity.hpp>
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#include <boost/function_types/result_type.hpp>
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namespace boost { namespace cnv
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{
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typedef ::boost::type_traits::yes_type yes_type;
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typedef ::boost::type_traits:: no_type no_type;
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template <bool has_operator, typename Functor, typename TypeOut>
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struct check_functor { BOOST_STATIC_CONSTANT(bool, value = false); };
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template<typename Func, typename TypeOut, class Enable =void>
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struct is_fun { BOOST_STATIC_CONSTANT(bool, value = false); };
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template <typename Functor, typename TypeOut>
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struct check_functor<true, Functor, TypeOut>
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{
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static yes_type test (TypeOut const&);
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static no_type test (...);
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static const bool value = sizeof(yes_type) == sizeof(test(((Functor*) 0)->operator()()));
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};
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template<typename Functor, typename TypeOut>
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struct is_fun<Functor, TypeOut,
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typename enable_if_c<is_class<Functor>::value && !is_convertible<Functor, TypeOut>::value, void>::type>
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{
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BOOST_DECLARE_HAS_MEMBER(has_funop, operator());
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BOOST_STATIC_CONSTANT(bool, value = (check_functor<has_funop<Functor>::value, Functor, TypeOut>::value));
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};
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template<typename Function, typename TypeOut>
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struct is_fun<Function, TypeOut,
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typename enable_if_c<
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function_types::is_function_pointer<Function>::value &&
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function_types::function_arity<Function>::value == 0 &&
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!is_same<Function, TypeOut>::value,
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void>::type>
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{
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typedef TypeOut out_type;
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typedef typename function_types::result_type<Function>::type func_out_type;
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BOOST_STATIC_CONSTANT(bool, value = (is_convertible<func_out_type, out_type>::value));
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};
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}}
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#endif // BOOST_CONVERT_IS_FUNCTION_HPP
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