// Copyright 2018-2019 Hans Dembinski
|
//
|
// 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 BOOST_HISTOGRAM_DETAIL_STATIC_IF_HPP
|
#define BOOST_HISTOGRAM_DETAIL_STATIC_IF_HPP
|
|
#include <type_traits>
|
#include <utility>
|
|
namespace boost {
|
namespace histogram {
|
namespace detail {
|
|
template <class T, class F, class... Args>
|
constexpr decltype(auto) static_if_impl(
|
std::true_type, T&& t, F&&,
|
Args&&... args) noexcept(noexcept(std::declval<T>()(std::declval<Args>()...))) {
|
return std::forward<T>(t)(std::forward<Args>(args)...);
|
}
|
|
template <class T, class F, class... Args>
|
constexpr decltype(auto) static_if_impl(
|
std::false_type, T&&, F&& f,
|
Args&&... args) noexcept(noexcept(std::declval<F>()(std::declval<Args>()...))) {
|
return std::forward<F>(f)(std::forward<Args>(args)...);
|
}
|
|
template <bool B, class... Ts>
|
constexpr decltype(auto) static_if_c(Ts&&... ts) noexcept(
|
noexcept(static_if_impl(std::integral_constant<bool, B>{}, std::declval<Ts>()...))) {
|
return static_if_impl(std::integral_constant<bool, B>{}, std::forward<Ts>(ts)...);
|
}
|
|
template <class Bool, class... Ts>
|
constexpr decltype(auto) static_if(Ts&&... ts) noexcept(
|
noexcept(static_if_impl(Bool{}, std::declval<Ts>()...))) {
|
return static_if_impl(Bool{}, std::forward<Ts>(ts)...);
|
}
|
|
} // namespace detail
|
} // namespace histogram
|
} // namespace boost
|
|
#endif
|
