122 lines
3.2 KiB
C++
122 lines
3.2 KiB
C++
#pragma once
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#include "snplib_concepts.h"
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namespace snplib
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{
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/* deduce callable's signature */
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// WARNING: it does not work for generic lambdas!
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// helper classes
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template <typename... Ts>
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struct snplib_func_traits_helper_t;
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template <typename R>
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struct snplib_func_traits_helper_t<R> {
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using ret_t = R;
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using args_t = std::tuple<>;
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using arg1_t = void;
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static constexpr size_t arity = 0;
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};
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template <typename R, typename Arg, typename... Args>
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struct snplib_func_traits_helper_t<R, Arg, Args...> {
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using ret_t = R;
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using args_t = std::tuple<Arg, Args...>;
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using arg1_t = Arg;
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static constexpr size_t arity = sizeof...(Args) + 1;
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};
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template <typename F>
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struct snplib_func_traits_t {
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// use of an empty struct here to match std::invoke_result behaivior (at least of GCC)
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};
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// special case
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template <>
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struct snplib_func_traits_t<std::nullptr_t> {
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using ret_t = std::nullptr_t;
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using args_t = std::tuple<>;
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using arg1_t = std::nullptr_t;
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static constexpr size_t arity = 0;
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};
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template <typename R, typename... Args>
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struct snplib_func_traits_t<R (*)(Args...)> : snplib_func_traits_helper_t<R, Args...> {
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};
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template <typename R, typename... Args>
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struct snplib_func_traits_t<R(Args...)> : snplib_func_traits_helper_t<R, Args...> {
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};
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template <typename C, typename R, typename... Args>
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struct snplib_func_traits_t<R (C::*)(Args...)> : snplib_func_traits_helper_t<R, Args...> {
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};
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template <typename C, typename R, typename... Args>
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struct snplib_func_traits_t<R (C::*)(Args...) const> : snplib_func_traits_helper_t<R, Args...> {
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};
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template <typename F>
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requires snplib_callable_c<F>
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struct snplib_func_traits_t<F> : snplib_func_traits_t<decltype(&F::operator())> {
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};
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template <typename F>
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struct snplib_func_traits_t<F&> : snplib_func_traits_t<F> {
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};
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template <typename F>
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struct snplib_func_traits_t<const F&> : snplib_func_traits_t<F> {
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};
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template <typename F>
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struct snplib_func_traits_t<F&&> : snplib_func_traits_t<F> {
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};
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template <typename T>
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using snplib_func_arg1_t = typename snplib_func_traits_t<T>::arg1_t;
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/* create a std::tuple from the input types except the last one*/
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template <typename... Ts>
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struct snplib_tuple_except_last_helper_t;
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template <typename T>
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struct snplib_tuple_except_last_helper_t<T> {
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using tuple_t = std::tuple<>;
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};
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template <typename T, typename... Ts>
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struct snplib_tuple_except_last_helper_t<T, Ts...> {
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using tuple_t =
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decltype(std::tuple_cat(std::declval<std::tuple<T>>(),
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std::declval<typename snplib_tuple_except_last_helper_t<Ts...>::tuple_t>()));
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};
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template <typename... Ts>
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using snplib_tuple_except_last_t = typename snplib_tuple_except_last_helper_t<Ts...>::tuple_t;
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template <typename... Ts>
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struct snplib_last_in_pack_helper_t;
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template <typename T>
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struct snplib_last_in_pack_helper_t<T> {
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using type = T;
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};
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template <typename T, typename... Ts>
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struct snplib_last_in_pack_helper_t<T, Ts...> {
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using type = typename snplib_last_in_pack_helper_t<Ts...>::type;
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};
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template <typename... Ts>
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using snplib_last_in_pack_t = typename snplib_last_in_pack_helper_t<Ts...>::type;
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} // namespace snplib
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