mirror of
https://github.com/bolero-MURAKAMI/Sprout
synced 2024-11-12 21:09:01 +00:00
94 lines
2.8 KiB
C++
94 lines
2.8 KiB
C++
/*=============================================================================
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Copyright (c) 2011-2015 Bolero MURAKAMI
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https://github.com/bolero-MURAKAMI/Sprout
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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 SPROUT_STATEFUL_COUNTER_HPP
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#define SPROUT_STATEFUL_COUNTER_HPP
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#include <sprout/config.hpp>
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#include <sprout/type_traits/integral_constant.hpp>
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namespace sprout {
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#ifndef SPROUT_CONFIG_DISABLE_CONSTEXPR
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namespace counter_detail {
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#if defined(__GNUC__) && !defined(__clang__)
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# pragma GCC diagnostic push
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# pragma GCC diagnostic ignored "-Wnon-template-friend"
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#endif
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#if defined(__clang__)
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# pragma clang diagnostic push
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# pragma clang diagnostic ignored "-Wundefined-inline"
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#endif
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template<int N>
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struct tag {
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friend SPROUT_CONSTEXPR int adl_counter(sprout::counter_detail::tag<N>);
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};
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#if defined(__clang__)
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# pragma clang diagnostic pop
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#endif
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#if defined(__GNUC__) && !defined(__clang__)
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# pragma GCC diagnostic pop
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#endif
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template<int N>
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struct state {
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friend SPROUT_CONSTEXPR int adl_counter(sprout::counter_detail::tag<N>) {
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return N;
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}
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SPROUT_STATIC_CONSTEXPR int value = N;
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};
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template<int N>
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SPROUT_CONSTEXPR_OR_CONST int sprout::counter_detail::state<N>::value;
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template<int N, int = adl_counter(sprout::counter_detail::tag<N>())>
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SPROUT_CONSTEXPR bool check_impl(int, sprout::counter_detail::tag<N>) {
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return true;
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}
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template<int N>
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SPROUT_CONSTEXPR bool check_impl(long, sprout::counter_detail::tag<N>) {
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return false;
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}
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template<int N>
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SPROUT_CONSTEXPR bool check(bool R = sprout::counter_detail::check_impl(0, sprout::counter_detail::tag<N>())) {
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return R;
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}
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template<int N>
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SPROUT_CONSTEXPR int counter_impl(sprout::false_type, sprout::counter_detail::tag<N>) {
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return 0;
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}
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template<int N>
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SPROUT_CONSTEXPR int counter_impl(
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sprout::true_type, sprout::counter_detail::tag<N>,
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int R = !sprout::counter_detail::check<N>() ? N
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: counter_impl(sprout::bool_constant<sprout::counter_detail::check<N>()>(), sprout::counter_detail::tag<N + 1>())
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)
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{
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return R;
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}
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template<int N = 0>
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SPROUT_CONSTEXPR int counter(int R = sprout::counter_detail::counter_impl(sprout::true_type(), sprout::counter_detail::tag<N>())) {
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return R;
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}
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} // namespace counter_detail
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//
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// counter
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//
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template<
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int N = 1,
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int R = sprout::counter_detail::state<
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sprout::counter_detail::counter() + N - 1
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>::value
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>
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SPROUT_CONSTEXPR int counter() {
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return R;
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}
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#endif
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} // namespace sprout
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#endif // #ifndef SPROUT_STATEFUL_COUNTER_HPP
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