vmap/libs/generic/functional.h

214 lines
4.2 KiB
C++

#if !defined( INCLUDED_FUNCTIONAL_H )
#define INCLUDED_FUNCTIONAL_H
#include <functional>
#include <tuple>
namespace detail {
template<int N>
struct rank : rank<N - 1> {
};
template<>
struct rank<0> {
};
struct get_func {
template<class T>
struct wrapper {
using type = T;
};
template<class F>
using func_member = wrapper<typename F::func>;
template<class F>
static wrapper<func_member<F> > test(rank<2>) {
return {};
}
template<class F>
struct func_lambda {
using type = typename func_lambda<decltype(&F::operator())>::type;
};
template<class R, class ... Ts>
struct func_lambda<R (*)(Ts...)> {
using type = R(Ts ...);
};
template<class Object, class R, class ... Ts>
struct func_lambda<R (Object::*)(Ts...) const> {
using type = R(Ts ...);
};
template<class Object, class R, class ... Ts>
struct func_lambda<R (Object::*)(Ts...)> {
using type = R(Ts ...);
};
template<class F, class = func_lambda<F> >
static wrapper<func_lambda<F> > test(rank<1>) {
return {};
}
};
template<class F>
struct Fn;
template<class R, class ... Ts>
struct Fn<R(Ts...)> {
using result_type = R;
template<int N>
using get = typename std::tuple_element<N, std::tuple<Ts...> >::type;
};
}
template<class Caller>
using get_func = typename decltype(detail::get_func::test<Caller>(detail::rank<2>{}))::type::type;
template<class Caller>
using get_result_type = typename detail::Fn<get_func<Caller> >::result_type;
template<class Caller, int N>
using get_argument = typename detail::Fn<get_func<Caller> >::template get<N>;
namespace detail {
template<class F>
class FunctionN;
template<class R, class ... Ts>
class FunctionN<R(Ts...)> {
public:
template<R(*f)(Ts...)>
class instance {
public:
using func = R(Ts ...);
static R call(Ts... args) {
return (f)(args ...);
}
};
};
}
template<class F, F *func>
using Function = typename detail::FunctionN<F>::template instance<func>;
namespace detail {
template<class Object, class F>
struct MemberFunction;
template<class Object, class R, class ... Ts>
struct MemberFunction<Object, R(Ts...)> {
using type = R (Object::*)(Ts...);
using type_const = R (Object::*)(Ts...) const;
};
}
namespace detail {
template<class Object, class F>
class MemberN;
template<class Object, class R, class ... Ts>
class MemberN<Object, R(Ts...)> {
public:
template<R(Object::*f)(Ts...)>
class instance {
public:
using func = R(Object &, Ts ...);
static R call(Object &object, Ts... args) {
return (object.*f)(args ...);
}
};
};
}
template<class Object, class F>
using MemberFunction = typename detail::MemberFunction<Object, F>::type;
template<class Object, class F, MemberFunction<Object, F> func>
using Member = typename detail::MemberN<Object, F>::template instance<func>;
namespace detail {
template<class Object, class F>
class ConstMemberN;
template<class Object, class R, class ... Ts>
class ConstMemberN<Object, R(Ts...)> {
public:
template<R(Object::*f)(Ts...) const>
class instance {
public:
using func = R(const Object &, Ts ...);
static R call(const Object &object, Ts... args) {
return (object.*f)(args ...);
}
};
};
}
template<class Object, class F>
using ConstMemberFunction = typename detail::MemberFunction<Object, F>::type_const;
template<class Object, class F, ConstMemberFunction<Object, F> func>
using ConstMember = typename detail::ConstMemberN<Object, F>::template instance<func>;
// misc
namespace detail {
template<int ...>
struct seq {
};
template<int N, int... S>
struct gens : gens<N - 1, N - 1, S...> {
};
template<int... S>
struct gens<0, S...> {
using type = seq<S...>;
};
template<int N>
using seq_new = typename gens<N>::type;
template<class Functor, class F>
class FunctorNInvoke;
template<class Functor, class R, class ... Ts>
class FunctorNInvoke<Functor, R(Ts...)> {
std::tuple<Ts...> args;
template<class T>
struct caller;
template<int ... I>
struct caller<seq<I...> > {
static inline R call(FunctorNInvoke<Functor, R(Ts...)> *self, Functor functor) {
(void) self;
return functor(std::get<I>(self->args)...);
}
};
public:
FunctorNInvoke(Ts... args) : args(args ...) {
}
inline R operator()(Functor functor) {
return caller<seq_new<sizeof...(Ts)> >::call(this, functor);
}
};
}
template<class Functor>
using FunctorInvoke = detail::FunctorNInvoke<Functor, get_func<Functor> >;
#endif