// Copyright 2015-2019 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_DETECT_HPP
#define BOOST_HISTOGRAM_DETAIL_DETECT_HPP
#include <boost/histogram/fwd.hpp>
#include <boost/mp11/function.hpp> // mp_and, mp_or
#include <boost/mp11/integral.hpp> // mp_not
#include <boost/mp11/list.hpp> // mp_first
#include <iterator>
#include <tuple>
#include <type_traits>
// forward declaration
namespace boost {
namespace variant2 {
template <class...>
class variant;
} // namespace variant2
} // namespace boost
namespace boost {
namespace histogram {
namespace detail {
#define BOOST_HISTOGRAM_DETAIL_DETECT(name, cond) \
template <class U> \
struct name##_impl { \
typedef char yes[1]; \
typedef char no[2]; \
template <class T> \
static yes& test(T& t, decltype(cond, 0)); \
template <class T> \
static no& test(T&, float); \
using type = \
std::integral_constant<bool, (sizeof(test(std::declval<U&>(), 0)) == 1)>; \
}; \
template <class T> \
using name = typename name##_impl<T>::type
#define BOOST_HISTOGRAM_DETAIL_DETECT_BINARY(name, cond) \
template <class V, class W> \
struct name##_impl { \
typedef char yes[1]; \
typedef char no[2]; \
template <class T, class U> \
static yes& test(decltype(cond, 0)); \
template <class, class> \
static no& test(float); \
using type = std::integral_constant<bool, (sizeof(test<V, W>(0)) == 1)>; \
}; \
template <class T, class U = T> \
using name = typename name##_impl<T, U>::type
// reset has overloads, trying to get pmf in this case always fails
BOOST_HISTOGRAM_DETAIL_DETECT(has_method_reset, t.reset(0));
BOOST_HISTOGRAM_DETAIL_DETECT(is_indexable, t[0]);
BOOST_HISTOGRAM_DETAIL_DETECT_BINARY(
is_transform,
(std::declval<T&>().inverse(std::declval<T&>().forward(std::declval<U>()))));
BOOST_HISTOGRAM_DETAIL_DETECT(is_indexable_container,
(t[0], t.size(), std::begin(t), std::end(t)));
BOOST_HISTOGRAM_DETAIL_DETECT(is_vector_like,
(t[0], t.size(), t.resize(0), std::begin(t), std::end(t)));
BOOST_HISTOGRAM_DETAIL_DETECT(is_array_like, (t[0], t.size(), std::tuple_size<T>::value,
std::begin(t), std::end(t)));
BOOST_HISTOGRAM_DETAIL_DETECT(is_map_like, ((typename T::key_type*)nullptr,
(typename T::mapped_type*)nullptr,
std::begin(t), std::end(t)));
// ok: is_axis is false for axis::variant, because T::index is templated
BOOST_HISTOGRAM_DETAIL_DETECT(is_axis, (t.size(), &T::index));
BOOST_HISTOGRAM_DETAIL_DETECT(is_iterable, (std::begin(t), std::end(t)));
BOOST_HISTOGRAM_DETAIL_DETECT(is_iterator,
(typename std::iterator_traits<T>::iterator_category{}));
BOOST_HISTOGRAM_DETAIL_DETECT(is_streamable, (std::declval<std::ostream&>() << t));
BOOST_HISTOGRAM_DETAIL_DETECT(has_operator_preincrement, ++t);
BOOST_HISTOGRAM_DETAIL_DETECT_BINARY(has_operator_equal, (std::declval<const T&>() ==
std::declval<const U&>()));
BOOST_HISTOGRAM_DETAIL_DETECT_BINARY(has_operator_radd,
(std::declval<T&>() += std::declval<U>()));
BOOST_HISTOGRAM_DETAIL_DETECT_BINARY(has_operator_rsub,
(std::declval<T&>() -= std::declval<U>()));
BOOST_HISTOGRAM_DETAIL_DETECT_BINARY(has_operator_rmul,
(std::declval<T&>() *= std::declval<U>()));
BOOST_HISTOGRAM_DETAIL_DETECT_BINARY(has_operator_rdiv,
(std::declval<T&>() /= std::declval<U>()));
BOOST_HISTOGRAM_DETAIL_DETECT_BINARY(
has_method_eq, (std::declval<const T&>().operator==(std::declval<const U&>())));
BOOST_HISTOGRAM_DETAIL_DETECT(has_threading_support, (T::has_threading_support));
template <class T>
using is_storage = mp11::mp_and<is_indexable_container<T>, has_method_reset<T>,
has_threading_support<T>>;
template <class T>
using is_adaptible =
mp11::mp_and<mp11::mp_not<is_storage<T>>,
mp11::mp_or<is_vector_like<T>, is_array_like<T>, is_map_like<T>>>;
template <class T>
struct is_tuple_impl : std::false_type {};
template <class... Ts>
struct is_tuple_impl<std::tuple<Ts...>> : std::true_type {};
template <class T>
using is_tuple = typename is_tuple_impl<T>::type;
template <class T>
struct is_variant_impl : std::false_type {};
template <class... Ts>
struct is_variant_impl<boost::variant2::variant<Ts...>> : std::true_type {};
template <class T>
using is_variant = typename is_variant_impl<T>::type;
template <class T>
struct is_axis_variant_impl : std::false_type {};
template <class... Ts>
struct is_axis_variant_impl<axis::variant<Ts...>> : std::true_type {};
template <class T>
using is_axis_variant = typename is_axis_variant_impl<T>::type;
template <class T>
using is_any_axis = mp11::mp_or<is_axis<T>, is_axis_variant<T>>;
template <class T>
using is_sequence_of_axis = mp11::mp_and<is_iterable<T>, is_axis<mp11::mp_first<T>>>;
template <class T>
using is_sequence_of_axis_variant =
mp11::mp_and<is_iterable<T>, is_axis_variant<mp11::mp_first<T>>>;
template <class T>
using is_sequence_of_any_axis =
mp11::mp_and<is_iterable<T>, is_any_axis<mp11::mp_first<T>>>;
// poor-mans concept checks
template <class T, class = std::enable_if_t<is_storage<std::decay_t<T>>::value>>
struct requires_storage {};
template <class T, class _ = std::decay_t<T>,
class = std::enable_if_t<(is_storage<_>::value || is_adaptible<_>::value)>>
struct requires_storage_or_adaptible {};
template <class T, class = std::enable_if_t<is_iterator<std::decay_t<T>>::value>>
struct requires_iterator {};
template <class T, class = std::enable_if_t<
is_iterable<std::remove_cv_t<std::remove_reference_t<T>>>::value>>
struct requires_iterable {};
template <class T, class = std::enable_if_t<is_axis<std::decay_t<T>>::value>>
struct requires_axis {};
template <class T, class = std::enable_if_t<is_any_axis<std::decay_t<T>>::value>>
struct requires_any_axis {};
template <class T, class = std::enable_if_t<is_sequence_of_axis<std::decay_t<T>>::value>>
struct requires_sequence_of_axis {};
template <class T,
class = std::enable_if_t<is_sequence_of_axis_variant<std::decay_t<T>>::value>>
struct requires_sequence_of_axis_variant {};
template <class T,
class = std::enable_if_t<is_sequence_of_any_axis<std::decay_t<T>>::value>>
struct requires_sequence_of_any_axis {};
template <class T,
class = std::enable_if_t<is_any_axis<mp11::mp_first<std::decay_t<T>>>::value>>
struct requires_axes {};
template <class T, class U,
class = std::enable_if_t<is_transform<std::decay_t<T>, U>::value>>
struct requires_transform {};
} // namespace detail
} // namespace histogram
} // namespace boost
#endif