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- /*=============================================================================
- Copyright (c) 2001-2011 Joel de Guzman
- 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)
- ==============================================================================*/
- #if !defined(FUSION_REPLACE_IF_08182005_0946)
- #define FUSION_REPLACE_IF_08182005_0946
- #include <boost/fusion/support/config.hpp>
- #include <boost/utility/enable_if.hpp>
- #include <boost/mpl/if.hpp>
- #include <boost/type_traits/remove_reference.hpp>
- namespace boost { namespace fusion { namespace detail
- {
- template <bool is_convertible>
- struct replacer_if_helper;
- template <>
- struct replacer_if_helper<false>
- {
- template <typename U, typename F, typename T>
- BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
- static U&
- call(U& x, F&, T const&)
- {
- return x;
- }
- };
- template <>
- struct replacer_if_helper<true>
- {
- template <typename U, typename F, typename T>
- BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
- static U
- call(U& x, F& f, T const& new_value)
- {
- return f(x) ? new_value : x;
- }
- };
- template <typename F, typename T>
- struct replacer_if
- {
- BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
- replacer_if(F in_f, T const& in_new_value)
- : f(in_f), new_value(in_new_value) {}
- template<typename Params>
- struct result;
- template <typename F1, typename T1, typename U>
- struct result<replacer_if<F1, T1>(U)>
- {
- typedef typename remove_reference<U>::type value;
- typedef typename
- mpl::if_<is_convertible<T, value>, value, value const&>::type
- type;
- };
- template <typename U>
- BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
- typename result<replacer_if(U)>::type
- operator()(U const& x) const
- {
- return replacer_if_helper<is_convertible<T, U>::value>::
- call(x, f, new_value);
- }
- F f;
- T new_value;
- };
- }}}
- #endif
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