xref: /openbsd-src/gnu/llvm/libcxx/include/__tuple_dir/sfinae_helpers.h (revision 4bdff4bed0e3d54e55670334c7d0077db4170f86)

//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#ifndef _LIBCPP___TUPLE_SFINAE_HELPERS_H
#define _LIBCPP___TUPLE_SFINAE_HELPERS_H

#include <__config>
#include <__fwd/tuple.h>
#include <__tuple_dir/make_tuple_types.h>
#include <__tuple_dir/tuple_element.h>
#include <__tuple_dir/tuple_like_ext.h>
#include <__tuple_dir/tuple_size.h>
#include <__tuple_dir/tuple_types.h>
#include <__type_traits/enable_if.h>
#include <__type_traits/integral_constant.h>
#include <__type_traits/is_assignable.h>
#include <__type_traits/is_constructible.h>
#include <__type_traits/is_convertible.h>
#include <__type_traits/is_same.h>
#include <__type_traits/remove_cvref.h>
#include <__type_traits/remove_reference.h>
#include <cstddef>

#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#  pragma GCC system_header
#endif

_LIBCPP_BEGIN_NAMESPACE_STD

#ifndef _LIBCPP_CXX03_LANG

template <bool ..._Preds>
struct __all_dummy;

template <bool ..._Pred>
struct __all : _IsSame<__all_dummy<_Pred...>, __all_dummy<((void)_Pred, true)...>> {};

struct __tuple_sfinae_base {
  template <template <class, class...> class _Trait,
            class ..._LArgs, class ..._RArgs>
  static auto __do_test(__tuple_types<_LArgs...>, __tuple_types<_RArgs...>)
    -> __all<__enable_if_t<_Trait<_LArgs, _RArgs>::value, bool>{true}...>;
  template <template <class...> class>
  static auto __do_test(...) -> false_type;

  template <class _FromArgs, class _ToArgs>
  using __constructible = decltype(__do_test<is_constructible>(_ToArgs{}, _FromArgs{}));
  template <class _FromArgs, class _ToArgs>
  using __convertible = decltype(__do_test<is_convertible>(_FromArgs{}, _ToArgs{}));
  template <class _FromArgs, class _ToArgs>
  using __assignable = decltype(__do_test<is_assignable>(_ToArgs{}, _FromArgs{}));
};

// __tuple_convertible

template <class _Tp, class _Up, bool = __tuple_like_ext<__libcpp_remove_reference_t<_Tp> >::value,
                                bool = __tuple_like_ext<_Up>::value>
struct __tuple_convertible
    : public false_type {};

template <class _Tp, class _Up>
struct __tuple_convertible<_Tp, _Up, true, true>
    : public __tuple_sfinae_base::__convertible<
      typename __make_tuple_types<_Tp>::type
    , typename __make_tuple_types<_Up>::type
    >
{};

// __tuple_constructible

template <class _Tp, class _Up, bool = __tuple_like_ext<__libcpp_remove_reference_t<_Tp> >::value,
                                bool = __tuple_like_ext<_Up>::value>
struct __tuple_constructible
    : public false_type {};

template <class _Tp, class _Up>
struct __tuple_constructible<_Tp, _Up, true, true>
    : public __tuple_sfinae_base::__constructible<
      typename __make_tuple_types<_Tp>::type
    , typename __make_tuple_types<_Up>::type
    >
{};

// __tuple_assignable

template <class _Tp, class _Up, bool = __tuple_like_ext<__libcpp_remove_reference_t<_Tp> >::value,
                                bool = __tuple_like_ext<_Up>::value>
struct __tuple_assignable
    : public false_type {};

template <class _Tp, class _Up>
struct __tuple_assignable<_Tp, _Up, true, true>
    : public __tuple_sfinae_base::__assignable<
      typename __make_tuple_types<_Tp>::type
    , typename __make_tuple_types<_Up&>::type
    >
{};


template <size_t _Ip, class ..._Tp>
struct _LIBCPP_TEMPLATE_VIS tuple_element<_Ip, tuple<_Tp...> >
{
    typedef _LIBCPP_NODEBUG typename tuple_element<_Ip, __tuple_types<_Tp...> >::type type;
};

template <bool _IsTuple, class _SizeTrait, size_t _Expected>
struct __tuple_like_with_size_imp : false_type {};

template <class _SizeTrait, size_t _Expected>
struct __tuple_like_with_size_imp<true, _SizeTrait, _Expected>
    : integral_constant<bool, _SizeTrait::value == _Expected> {};

template <class _Tuple, size_t _ExpectedSize, class _RawTuple = __libcpp_remove_reference_t<_Tuple> >
using __tuple_like_with_size _LIBCPP_NODEBUG = __tuple_like_with_size_imp<
                                   __tuple_like_ext<_RawTuple>::value,
                                   tuple_size<_RawTuple>, _ExpectedSize
                              >;

struct _LIBCPP_TYPE_VIS __check_tuple_constructor_fail {

    static constexpr bool __enable_explicit_default() { return false; }
    static constexpr bool __enable_implicit_default() { return false; }
    template <class ...>
    static constexpr bool __enable_explicit() { return false; }
    template <class ...>
    static constexpr bool __enable_implicit() { return false; }
    template <class ...>
    static constexpr bool __enable_assign() { return false; }
};
#endif // !defined(_LIBCPP_CXX03_LANG)

#if _LIBCPP_STD_VER > 14

template <bool _CanCopy, bool _CanMove>
struct __sfinae_ctor_base {};
template <>
struct __sfinae_ctor_base<false, false> {
  __sfinae_ctor_base() = default;
  __sfinae_ctor_base(__sfinae_ctor_base const&) = delete;
  __sfinae_ctor_base(__sfinae_ctor_base &&) = delete;
  __sfinae_ctor_base& operator=(__sfinae_ctor_base const&) = default;
  __sfinae_ctor_base& operator=(__sfinae_ctor_base&&) = default;
};
template <>
struct __sfinae_ctor_base<true, false> {
  __sfinae_ctor_base() = default;
  __sfinae_ctor_base(__sfinae_ctor_base const&) = default;
  __sfinae_ctor_base(__sfinae_ctor_base &&) = delete;
  __sfinae_ctor_base& operator=(__sfinae_ctor_base const&) = default;
  __sfinae_ctor_base& operator=(__sfinae_ctor_base&&) = default;
};
template <>
struct __sfinae_ctor_base<false, true> {
  __sfinae_ctor_base() = default;
  __sfinae_ctor_base(__sfinae_ctor_base const&) = delete;
  __sfinae_ctor_base(__sfinae_ctor_base &&) = default;
  __sfinae_ctor_base& operator=(__sfinae_ctor_base const&) = default;
  __sfinae_ctor_base& operator=(__sfinae_ctor_base&&) = default;
};

template <bool _CanCopy, bool _CanMove>
struct __sfinae_assign_base {};
template <>
struct __sfinae_assign_base<false, false> {
  __sfinae_assign_base() = default;
  __sfinae_assign_base(__sfinae_assign_base const&) = default;
  __sfinae_assign_base(__sfinae_assign_base &&) = default;
  __sfinae_assign_base& operator=(__sfinae_assign_base const&) = delete;
  __sfinae_assign_base& operator=(__sfinae_assign_base&&) = delete;
};
template <>
struct __sfinae_assign_base<true, false> {
  __sfinae_assign_base() = default;
  __sfinae_assign_base(__sfinae_assign_base const&) = default;
  __sfinae_assign_base(__sfinae_assign_base &&) = default;
  __sfinae_assign_base& operator=(__sfinae_assign_base const&) = default;
  __sfinae_assign_base& operator=(__sfinae_assign_base&&) = delete;
};
template <>
struct __sfinae_assign_base<false, true> {
  __sfinae_assign_base() = default;
  __sfinae_assign_base(__sfinae_assign_base const&) = default;
  __sfinae_assign_base(__sfinae_assign_base &&) = default;
  __sfinae_assign_base& operator=(__sfinae_assign_base const&) = delete;
  __sfinae_assign_base& operator=(__sfinae_assign_base&&) = default;
};
#endif // _LIBCPP_STD_VER > 14

_LIBCPP_END_NAMESPACE_STD

#endif // _LIBCPP___TUPLE_SFINAE_HELPERS_H