#ifndef BOOST_ASIO_TRAITS_EQUALITY_COMPARABLE_HPP
#define BOOST_ASIO_TRAITS_EQUALITY_COMPARABLE_HPP
#if defined(_MSC_VER) && (_MSC_VER >= 1200)
# pragma once
#endif
#include <boost/asio/detail/config.hpp>
#include <boost/asio/detail/type_traits.hpp>
#if defined(BOOST_ASIO_HAS_WORKING_EXPRESSION_SFINAE)
# define BOOST_ASIO_HAS_DEDUCED_EQUALITY_COMPARABLE_TRAIT 1
#endif
namespace boost {
namespace asio {
namespace traits {
template <typename T, typename = void>
struct equality_comparable_default;
template <typename T, typename = void>
struct equality_comparable;
} namespace detail {
struct no_equality_comparable
{
static constexpr bool is_valid = false;
static constexpr bool is_noexcept = false;
};
#if defined(BOOST_ASIO_HAS_DEDUCED_EQUALITY_COMPARABLE_TRAIT)
template <typename T, typename = void>
struct equality_comparable_trait : no_equality_comparable
{
};
template <typename T>
struct equality_comparable_trait<T,
void_t<
decltype(
static_cast<void>(
static_cast<bool>(declval<const T>() == declval<const T>())
),
static_cast<void>(
static_cast<bool>(declval<const T>() != declval<const T>())
)
)
>>
{
static constexpr bool is_valid = true;
static constexpr bool is_noexcept =
noexcept(declval<const T>() == declval<const T>())
&& noexcept(declval<const T>() != declval<const T>());
};
#else
template <typename T, typename = void>
struct equality_comparable_trait :
conditional_t<
is_same<T, decay_t<T>>::value,
no_equality_comparable,
traits::equality_comparable<decay_t<T>>
>
{
};
#endif
} namespace traits {
template <typename T, typename>
struct equality_comparable_default : detail::equality_comparable_trait<T>
{
};
template <typename T, typename>
struct equality_comparable : equality_comparable_default<T>
{
};
} } }
#endif