79 lines
2.2 KiB
Plaintext
79 lines
2.2 KiB
Plaintext
|
/*=============================================================================
|
||
|
|
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_08182005_0841)
|
||
|
|
#define FUSION_REPLACE_08182005_0841
|
||
|
|
|
||
|
|
#include <boost/fusion/support/config.hpp>
|
||
|
|
#include <boost/type_traits/is_convertible.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_helper;
|
||
|
|
|
||
|
|
template <>
|
||
|
|
struct replacer_helper<false>
|
||
|
|
{
|
||
|
|
template <typename U, typename T>
|
||
|
|
BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
|
||
|
|
static U&
|
||
|
|
call(U& x, T const&, T const&)
|
||
|
|
{
|
||
|
|
return x;
|
||
|
|
}
|
||
|
|
};
|
||
|
|
|
||
|
|
template <>
|
||
|
|
struct replacer_helper<true>
|
||
|
|
{
|
||
|
|
template <typename U, typename T>
|
||
|
|
BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
|
||
|
|
static U
|
||
|
|
call(U& x, T const& old_value, T const& new_value)
|
||
|
|
{
|
||
|
|
return (x == old_value) ? new_value : x;
|
||
|
|
}
|
||
|
|
};
|
||
|
|
|
||
|
|
template <typename T>
|
||
|
|
struct replacer
|
||
|
|
{
|
||
|
|
BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
|
||
|
|
replacer(T const& in_old_value, T const& in_new_value)
|
||
|
|
: old_value(in_old_value), new_value(in_new_value) {}
|
||
|
|
|
||
|
|
template<typename Sig>
|
||
|
|
struct result;
|
||
|
|
|
||
|
|
template <typename U1, typename U2>
|
||
|
|
struct result<replacer<U1>(U2)>
|
||
|
|
{
|
||
|
|
typedef typename remove_reference<U2>::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(U)>::type
|
||
|
|
operator()(U const& x) const
|
||
|
|
{
|
||
|
|
return replacer_helper<is_convertible<T, U>::value>::
|
||
|
|
call(x, old_value, new_value);
|
||
|
|
}
|
||
|
|
|
||
|
|
T old_value;
|
||
|
|
T new_value;
|
||
|
|
};
|
||
|
|
}}}
|
||
|
|
|
||
|
|
#endif
|
||
|
|
|