]>
Commit | Line | Data |
---|---|---|
7c673cae FG |
1 | // Boost.Range library |
2 | // | |
3 | // Copyright Neil Groves 2014. Use, modification and | |
4 | // distribution is subject to the Boost Software License, Version | |
5 | // 1.0. (See accompanying file LICENSE_1_0.txt or copy at | |
6 | // http://www.boost.org/LICENSE_1_0.txt) | |
7 | // | |
8 | // For more information, see http://www.boost.org/libs/range/ | |
9 | // | |
10 | #ifndef BOOST_RANGE_DETAIL_DEFAULT_CONSTRUCTIBLE_UNARY_FN_HPP_INCLUDED | |
11 | #define BOOST_RANGE_DETAIL_DEFAULT_CONSTRUCTIBLE_UNARY_FN_HPP_INCLUDED | |
12 | ||
13 | #include <boost/optional/optional.hpp> | |
14 | #include <boost/mpl/if.hpp> | |
15 | #include <boost/type_traits/has_trivial_constructor.hpp> | |
16 | ||
17 | namespace boost | |
18 | { | |
19 | namespace range_detail | |
20 | { | |
21 | ||
22 | template<typename F, typename R> | |
23 | class default_constructible_unary_fn_wrapper | |
24 | { | |
25 | public: | |
26 | typedef R result_type; | |
27 | ||
28 | default_constructible_unary_fn_wrapper() | |
29 | { | |
30 | } | |
31 | default_constructible_unary_fn_wrapper(const F& source) | |
32 | : m_impl(source) | |
33 | { | |
34 | } | |
35 | template<typename Arg> | |
36 | R operator()(const Arg& arg) const | |
37 | { | |
38 | BOOST_ASSERT(m_impl); | |
39 | return (*m_impl)(arg); | |
40 | } | |
41 | template<typename Arg> | |
42 | R operator()(Arg& arg) const | |
43 | { | |
44 | BOOST_ASSERT(m_impl); | |
45 | return (*m_impl)(arg); | |
46 | } | |
47 | private: | |
48 | boost::optional<F> m_impl; | |
49 | }; | |
50 | ||
51 | template<typename F, typename R> | |
52 | struct default_constructible_unary_fn_gen | |
53 | { | |
54 | typedef typename boost::mpl::if_< | |
55 | boost::has_trivial_default_constructor<F>, | |
56 | F, | |
57 | default_constructible_unary_fn_wrapper<F,R> | |
58 | >::type type; | |
59 | }; | |
60 | ||
61 | } // namespace range_detail | |
62 | } // namespace boost | |
63 | ||
64 | #endif // include guard |