]>
Commit | Line | Data |
---|---|---|
7c673cae FG |
1 | /*! |
2 | @file | |
3 | Defines `boost::hana::min`. | |
4 | ||
5 | @copyright Louis Dionne 2013-2016 | |
6 | Distributed under the Boost Software License, Version 1.0. | |
7 | (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt) | |
8 | */ | |
9 | ||
10 | #ifndef BOOST_HANA_MIN_HPP | |
11 | #define BOOST_HANA_MIN_HPP | |
12 | ||
13 | #include <boost/hana/fwd/min.hpp> | |
14 | ||
15 | #include <boost/hana/concept/orderable.hpp> | |
16 | #include <boost/hana/config.hpp> | |
17 | #include <boost/hana/core/dispatch.hpp> | |
18 | #include <boost/hana/if.hpp> | |
19 | #include <boost/hana/less.hpp> | |
20 | ||
21 | ||
22 | BOOST_HANA_NAMESPACE_BEGIN | |
23 | //! @cond | |
24 | template <typename X, typename Y> | |
25 | constexpr decltype(auto) min_t::operator()(X&& x, Y&& y) const { | |
26 | using T = typename hana::tag_of<X>::type; | |
27 | using U = typename hana::tag_of<Y>::type; | |
28 | using Min = BOOST_HANA_DISPATCH_IF(decltype(min_impl<T, U>{}), | |
29 | hana::Orderable<T>::value && | |
30 | hana::Orderable<U>::value | |
31 | ); | |
32 | ||
33 | #ifndef BOOST_HANA_CONFIG_DISABLE_CONCEPT_CHECKS | |
34 | static_assert(hana::Orderable<T>::value, | |
35 | "hana::min(x, y) requires 'x' to be Orderable"); | |
36 | ||
37 | static_assert(hana::Orderable<U>::value, | |
38 | "hana::min(x, y) requires 'y' to be Orderable"); | |
39 | #endif | |
40 | ||
41 | return Min::apply(static_cast<X&&>(x), static_cast<Y&&>(y)); | |
42 | } | |
43 | //! @endcond | |
44 | ||
45 | template <typename T, typename U, bool condition> | |
46 | struct min_impl<T, U, when<condition>> : default_ { | |
47 | template <typename X, typename Y> | |
48 | static constexpr decltype(auto) apply(X&& x, Y&& y) { | |
49 | decltype(auto) cond = hana::less(x, y); | |
50 | return hana::if_(static_cast<decltype(cond)&&>(cond), | |
51 | static_cast<X&&>(x), | |
52 | static_cast<Y&&>(y) | |
53 | ); | |
54 | } | |
55 | }; | |
56 | BOOST_HANA_NAMESPACE_END | |
57 | ||
58 | #endif // !BOOST_HANA_MIN_HPP |