124 lines
3.1 KiB
C++
124 lines
3.1 KiB
C++
//
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// traits/static_require.hpp
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// ~~~~~~~~~~~~~~~~~~~~~~~~~
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//
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// Copyright (c) 2003-2021 Christopher M. Kohlhoff (chris at kohlhoff dot com)
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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//
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#ifndef ASIO_TRAITS_STATIC_REQUIRE_HPP
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#define ASIO_TRAITS_STATIC_REQUIRE_HPP
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#if defined(_MSC_VER) && (_MSC_VER >= 1200)
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# pragma once
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#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
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#include "asio/detail/config.hpp"
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#include "asio/detail/type_traits.hpp"
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#include "asio/traits/static_query.hpp"
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#if defined(ASIO_HAS_DECLTYPE) \
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&& defined(ASIO_HAS_NOEXCEPT)
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# define ASIO_HAS_DEDUCED_STATIC_REQUIRE_TRAIT 1
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#endif // defined(ASIO_HAS_DECLTYPE)
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// && defined(ASIO_HAS_NOEXCEPT)
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#include "asio/detail/push_options.hpp"
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namespace asio {
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namespace traits {
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template <typename T, typename Property, typename = void>
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struct static_require_default;
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template <typename T, typename Property, typename = void>
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struct static_require;
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} // namespace traits
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namespace detail {
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struct no_static_require
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{
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ASIO_STATIC_CONSTEXPR(bool, is_valid = false);
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};
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template <typename T, typename Property, typename = void>
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struct static_require_trait :
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conditional<
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is_same<T, typename decay<T>::type>::value
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&& is_same<Property, typename decay<Property>::type>::value,
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no_static_require,
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traits::static_require<
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typename decay<T>::type,
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typename decay<Property>::type>
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>::type
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{
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};
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#if defined(ASIO_HAS_DEDUCED_STATIC_REQUIRE_TRAIT)
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#if defined(ASIO_HAS_WORKING_EXPRESSION_SFINAE)
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template <typename T, typename Property>
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struct static_require_trait<T, Property,
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typename enable_if<
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decay<Property>::type::value() == traits::static_query<T, Property>::value()
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>::type>
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{
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ASIO_STATIC_CONSTEXPR(bool, is_valid = true);
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};
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#else // defined(ASIO_HAS_WORKING_EXPRESSION_SFINAE)
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false_type static_require_test(...);
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template <typename T, typename Property>
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true_type static_require_test(T*, Property*,
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typename enable_if<
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Property::value() == traits::static_query<T, Property>::value()
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>::type* = 0);
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template <typename T, typename Property>
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struct has_static_require
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{
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ASIO_STATIC_CONSTEXPR(bool, value =
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decltype((static_require_test)(
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static_cast<T*>(0), static_cast<Property*>(0)))::value);
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};
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template <typename T, typename Property>
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struct static_require_trait<T, Property,
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typename enable_if<
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has_static_require<typename decay<T>::type,
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typename decay<Property>::type>::value
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>::type>
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{
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ASIO_STATIC_CONSTEXPR(bool, is_valid = true);
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};
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#endif // defined(ASIO_HAS_WORKING_EXPRESSION_SFINAE)
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#endif // defined(ASIO_HAS_DEDUCED_STATIC_REQUIRE_TRAIT)
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} // namespace detail
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namespace traits {
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template <typename T, typename Property, typename>
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struct static_require_default : detail::static_require_trait<T, Property>
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{
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};
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template <typename T, typename Property, typename>
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struct static_require : static_require_default<T, Property>
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{
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};
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} // namespace traits
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} // namespace asio
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#include "asio/detail/pop_options.hpp"
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#endif // ASIO_TRAITS_STATIC_REQUIRE_HPP
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