Sprout/sprout/container/detail/range_back.hpp
2019-01-07 17:47:17 +09:00

128 lines
4.5 KiB
C++

/*=============================================================================
Copyright (c) 2011-2019 Bolero MURAKAMI
https://github.com/bolero-MURAKAMI/Sprout
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)
=============================================================================*/
#ifndef SPROUT_CONTAINER_DETAIL_RANGE_BACK_HPP
#define SPROUT_CONTAINER_DETAIL_RANGE_BACK_HPP
#include <utility>
#include <type_traits>
#include <sprout/config.hpp>
#include <sprout/type_traits/integral_constant.hpp>
#include <sprout/type_traits/identity.hpp>
#include <sprout/container/traits_fwd.hpp>
#include <sprout/container/container_traits.hpp>
#include <sprout/container/range_functions_fwd.hpp>
#include <sprout/container/detail/range_begin.hpp>
#include <sprout/iterator/operation.hpp>
#include <sprout/utility/as_const.hpp>
#include <sprout/adl/not_found.hpp>
namespace sprout_adl {
sprout::not_found_via_adl range_back(...);
} // namespace sprout_adl
namespace sprout {
namespace detail {
template<typename T>
struct has_mem_back_test {
public:
template<
typename U = T,
typename = typename sprout::identity<decltype(std::declval<U>().back())>::type
>
static sprout::true_type test(int);
static sprout::false_type test(...);
};
#if defined(_MSC_VER) && (_MSC_VER > 1900)
template<typename T, typename Base_ = typename sprout::identity<decltype(sprout::detail::has_mem_back_test<T>::test(0))>::type>
struct has_mem_back
: public Base_
{};
#else
template<typename T>
struct has_mem_back
: public sprout::identity<decltype(sprout::detail::has_mem_back_test<T>::test(0))>::type
{};
#endif
template<typename T>
struct is_substitutable_const_back
: public sprout::bool_constant<
sprout::is_const_reference_cast_convertible<
typename sprout::container_traits<T const>::reference,
typename sprout::container_traits<T>::reference
>::value
&& (
sprout::detail::has_mem_back<T const>::value
|| sprout::detail::has_mem_begin<T const>::value
|| sprout::detail::has_adl_begin_without_sprout<T const&>::value
)
>
{};
template<typename Container>
inline SPROUT_CONSTEXPR typename std::enable_if<
sprout::detail::is_substitutable_const_back<Container>::value,
typename sprout::container_traits<Container>::reference
>::type
range_back_impl(Container& cont) {
typedef typename sprout::container_traits<Container>::reference type;
return sprout::const_reference_cast<type>(sprout::back(sprout::as_const(cont)));
}
template<typename Container>
inline SPROUT_CONSTEXPR typename std::enable_if<
!sprout::detail::is_substitutable_const_back<Container>::value
&& sprout::detail::has_mem_back<Container>::value
,
typename sprout::container_traits<Container>::reference
>::type
range_back_impl(Container& cont) {
return cont.back();
}
template<typename Container>
inline SPROUT_CONSTEXPR typename std::enable_if<
!sprout::detail::is_substitutable_const_back<Container>::value
&& !sprout::detail::has_mem_back<Container>::value
,
typename sprout::container_traits<Container>::reference
>::type
range_back_impl(Container& cont) {
return *sprout::begin(cont);
}
template<typename Container>
inline SPROUT_CONSTEXPR typename std::enable_if<
sprout::detail::has_mem_back<Container const>::value,
typename sprout::container_traits<Container const>::reference
>::type
range_back_impl(Container const& cont) {
return cont.back();
}
template<typename Container>
inline SPROUT_CONSTEXPR typename std::enable_if<
!sprout::detail::has_mem_back<Container const>::value,
typename sprout::container_traits<Container const>::reference
>::type
range_back_impl(Container const& cont) {
return *sprout::next(sprout::begin(cont), sprout::size(cont) - 1);
}
} // namespace detail
} // namespace sprout
namespace sprout_container_range_detail {
template<typename Container>
inline SPROUT_CONSTEXPR typename sprout::container_traits<Container>::reference
range_back(Container& cont) {
return sprout::detail::range_back_impl(cont);
}
template<typename Container>
inline SPROUT_CONSTEXPR typename sprout::container_traits<Container const>::reference
range_back(Container const& cont) {
return sprout::detail::range_back_impl(cont);
}
} // namespace sprout_container_range_detail
#endif // #ifndef SPROUT_CONTAINER_DETAIL_RANGE_BACK_HPP