Sprout/sprout/stateful/counter.hpp
2015-05-14 19:52:27 +09:00

107 lines
2.9 KiB
C++

/*=============================================================================
Copyright (c) 2011-2015 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_STATEFUL_COUNTER_HPP
#define SPROUT_STATEFUL_COUNTER_HPP
#include <sprout/config.hpp>
#include <sprout/workaround/std/cstddef.hpp>
namespace sprout {
#ifndef SPROUT_CONFIG_DISABLE_CONSTEXPR
namespace detail {
SPROUT_STATIC_CONSTEXPR std::size_t counter_default_call_limit = 128;
} // namespace detail
namespace counter_detail {
#if defined(__GNUC__) && !defined(__clang__)
# pragma GCC diagnostic push
# pragma GCC diagnostic ignored "-Wnon-template-friend"
#endif
#if defined(__clang__)
# pragma clang diagnostic push
# pragma clang diagnostic ignored "-Wundefined-inline"
#endif
template<int N>
struct tag {
friend SPROUT_CONSTEXPR int adl_counter(sprout::counter_detail::tag<N>);
};
#if defined(__clang__)
# pragma clang diagnostic pop
#endif
#if defined(__GNUC__) && !defined(__clang__)
# pragma GCC diagnostic pop
#endif
template<int N>
struct state {
friend SPROUT_CONSTEXPR int adl_counter(sprout::counter_detail::tag<N>) {
return N;
}
SPROUT_STATIC_CONSTEXPR int value = N - 1;
};
template<int N>
SPROUT_CONSTEXPR_OR_CONST int sprout::counter_detail::state<N>::value;
template<>
struct state<1> {
friend SPROUT_CONSTEXPR int adl_counter(sprout::counter_detail::tag<1>) {
return 1;
}
static SPROUT_CONSTEXPR int value = 0;
};
SPROUT_CONSTEXPR_OR_CONST int sprout::counter_detail::state<1>::value;
template<int N, int R = adl_counter(sprout::counter_detail::tag<N>())>
SPROUT_CONSTEXPR int counter(
int, sprout::counter_detail::tag<N>
)
{
return R;
}
SPROUT_CONSTEXPR int counter(
long, sprout::counter_detail::tag<0>
)
{
return 0;
}
template<int N>
SPROUT_CONSTEXPR int counter(
long, sprout::counter_detail::tag<N>,
int R = counter(0, sprout::counter_detail::tag<N - 1>())
)
{
return R;
}
} // namespace counter_detail
//
// counter
// counter_before
//
template<
std::size_t Limit = sprout::detail::counter_default_call_limit,
int R = sprout::counter_detail::state<
sprout::counter_detail::counter(0, sprout::counter_detail::tag<Limit>()) + 1
>::value
>
SPROUT_CONSTEXPR int counter() {
return R;
}
template<
std::size_t Limit = sprout::detail::counter_default_call_limit,
int R = sprout::counter_detail::state<
sprout::counter_detail::counter(0, sprout::counter_detail::tag<Limit>())
>::value
>
SPROUT_CONSTEXPR int counter_before() {
return R;
}
#endif
} // namespace sprout
#endif // #ifndef SPROUT_STATEFUL_COUNTER_HPP