utility

// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// 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_UTILITY
#define _LIBCPP_UTILITY

/*
    utility synopsis

#include <initializer_list>

namespace std
{

template <class T>
    void
    swap(T& a, T& b);

namespace rel_ops
{
    template<class T> bool operator!=(const T&, const T&);
    template<class T> bool operator> (const T&, const T&);
    template<class T> bool operator<=(const T&, const T&);
    template<class T> bool operator>=(const T&, const T&);
}

template<class T>
void
swap(T& a, T& b) noexcept(is_nothrow_move_constructible<T>::value &&
                          is_nothrow_move_assignable<T>::value);

template <class T, size_t N>
void
swap(T (&a)[N], T (&b)[N]) noexcept(noexcept(swap(*a, *b)));

template <class T> T&& forward(typename remove_reference<T>::type& t) noexcept;  // constexpr in C++14
template <class T> T&& forward(typename remove_reference<T>::type&& t) noexcept; // constexpr in C++14

template <typename T>
[[nodiscard]] constexpr
auto forward_like(auto&& x) noexcept -> see below;                               // since C++23

template <class T> typename remove_reference<T>::type&& move(T&&) noexcept;      // constexpr in C++14

template <class T>
    typename conditional
    <
        !is_nothrow_move_constructible<T>::value && is_copy_constructible<T>::value,
        const T&,
        T&&
    >::type
    move_if_noexcept(T& x) noexcept; // constexpr in C++14

template <class T> constexpr add_const_t<T>& as_const(T& t) noexcept;      // C++17
template <class T>                      void as_const(const T&&) = delete; // C++17

template <class T> typename add_rvalue_reference<T>::type declval() noexcept;

template<class T, class U> constexpr bool cmp_equal(T t, U u) noexcept;         // C++20
template<class T, class U> constexpr bool cmp_not_equal(T t, U u) noexcept;     // C++20
template<class T, class U> constexpr bool cmp_less(T t, U u) noexcept;          // C++20
template<class T, class U> constexpr bool cmp_greater(T t, U u) noexcept;       // C++20
template<class T, class U> constexpr bool cmp_less_equal(T t, U u) noexcept;    // C++20
template<class T, class U> constexpr bool cmp_greater_equal(T t, U u) noexcept; // C++20
template<class R, class T> constexpr bool in_range(T t) noexcept;               // C++20

template <class T1, class T2>
struct pair
{
    typedef T1 first_type;
    typedef T2 second_type;

    T1 first;
    T2 second;

    pair(const pair&) = default;
    pair(pair&&) = default;
    explicit(see-below) constexpr pair();
    explicit(see-below) pair(const T1& x, const T2& y);                          // constexpr in C++14
    template <class U = T1, class V = T2> explicit(see-below) pair(U&&, V&&);    // constexpr in C++14
    template <class U, class V> constexpr explicit(see-below) pair(pair<U, V>&); // since C++23
    template <class U, class V> explicit(see-below) pair(const pair<U, V>& p);   // constexpr in C++14
    template <class U, class V> explicit(see-below) pair(pair<U, V>&& p);        // constexpr in C++14
    template <class U, class V>
    constexpr explicit(see-below) pair(const pair<U, V>&&);                      // since C++23
    template <pair-like P> constexpr explicit(see-below) pair(P&&);              // since C++23
    template <class... Args1, class... Args2>
        pair(piecewise_construct_t, tuple<Args1...> first_args,                  // constexpr in C++20
                                    tuple<Args2...> second_args);

    constexpr const pair& operator=(const pair& p) const;                        // since C++23
    template <class U, class V> pair& operator=(const pair<U, V>& p);            // constexpr in C++20
    template <class U, class V>
    constexpr const pair& operator=(const pair<U, V>& p) const;                  // since C++23
    pair& operator=(pair&& p) noexcept(is_nothrow_move_assignable<T1>::value &&
                                       is_nothrow_move_assignable<T2>::value);   // constexpr in C++20
    constexpr const pair& operator=(pair&& p) const;                             // since C++23
    template <class U, class V> pair& operator=(pair<U, V>&& p);                 // constexpr in C++20
    template <class U, class V>
    constexpr const pair& operator=(pair<U, V>&& p) const;                       // since C++23
    template <pair-like P> constexpr pair& operator=(P&&);                       // since C++23
    template <pair-like P> constexpr const pair& operator=(P&&) const;           // since C++23

    void swap(pair& p) noexcept(is_nothrow_swappable_v<T1> &&
                                is_nothrow_swappable_v<T2>);                     // constexpr in C++20
    constexpr void swap(const pair& p) const noexcept(see below);                // since C++23
};

template<class T1, class T2, class U1, class U2, template<class> class TQual, template<class> class UQual>
struct basic_common_reference<pair<T1, T2>, pair<U1, U2>, TQual, UQual>;         // since C++23

template<class T1, class T2, class U1, class U2>
struct common_type<pair<T1, T2>, pair<U1, U2>>;                                  // since C++23

template<class T1, class T2> pair(T1, T2) -> pair<T1, T2>;

template <class T1, class T2, class U1, class U2>
bool operator==(const pair<T1,T2>&, const pair<U1,U2>&);                         // constexpr in C++14
template <class T1, class T2, class U1, class U2>
bool operator!=(const pair<T1,T2>&, const pair<U1,U2>&);                         // constexpr in C++14, removed in C++20
template <class T1, class T2, class U1, class U2>
bool operator< (const pair<T1,T2>&, const pair<U1,U2>&);                         // constexpr in C++14, removed in C++20
template <class T1, class T2, class U1, class U2>
bool operator> (const pair<T1,T2>&, const pair<U1,U2>&);                         // constexpr in C++14, removed in C++20
template <class T1, class T2, class U1, class U2>
bool operator>=(const pair<T1,T2>&, const pair<U1,U2>&);                         // constexpr in C++14, removed in C++20
template <class T1, class T2, class U1, class U2>
bool operator<=(const pair<T1,T2>&, const pair<U1,U2>&);                         // constexpr in C++14, removed in C++20
template <class T1, class T2, class U1, class U2>
  constexpr common_comparison_type_t<synth-three-way-result<T1,U1>,
                                     synth-three-way-result<T2,U2>>
    operator<=>(const pair<T1,T2>&, const pair<U1,U2>&);                         // C++20

template <class T1, class T2> pair<V1, V2> make_pair(T1&&, T2&&);                // constexpr in C++14
template <class T1, class T2>
void
swap(pair<T1, T2>& x, pair<T1, T2>& y) noexcept(noexcept(x.swap(y)));            // constexpr in C++20

template<class T1, class T2>                                                     // since C++23
constexpr void swap(const pair<T1, T2>& x, const pair<T1, T2>& y) noexcept(noexcept(x.swap(y)));

struct piecewise_construct_t { explicit piecewise_construct_t() = default; };
inline constexpr piecewise_construct_t piecewise_construct = piecewise_construct_t();

template <class T> struct tuple_size;
template <size_t I, class T> struct tuple_element;

template <class T1, class T2> struct tuple_size<pair<T1, T2> >;
template <class T1, class T2> struct tuple_element<0, pair<T1, T2> >;
template <class T1, class T2> struct tuple_element<1, pair<T1, T2> >;

template<size_t I, class T1, class T2>
    typename tuple_element<I, pair<T1, T2> >::type&
    get(pair<T1, T2>&) noexcept; // constexpr in C++14

template<size_t I, class T1, class T2>
    const typename tuple_element<I, pair<T1, T2> >::type&
    get(const pair<T1, T2>&) noexcept; // constexpr in C++14

template<size_t I, class T1, class T2>
    typename tuple_element<I, pair<T1, T2> >::type&&
    get(pair<T1, T2>&&) noexcept; // constexpr in C++14

template<size_t I, class T1, class T2>
    const typename tuple_element<I, pair<T1, T2> >::type&&
    get(const pair<T1, T2>&&) noexcept; // constexpr in C++14

template<class T1, class T2>
    constexpr T1& get(pair<T1, T2>&) noexcept; // C++14

template<class T1, class T2>
    constexpr const T1& get(const pair<T1, T2>&) noexcept; // C++14

template<class T1, class T2>
    constexpr T1&& get(pair<T1, T2>&&) noexcept; // C++14

template<class T1, class T2>
    constexpr const T1&& get(const pair<T1, T2>&&) noexcept; // C++14

template<class T1, class T2>
    constexpr T1& get(pair<T2, T1>&) noexcept; // C++14

template<class T1, class T2>
    constexpr const T1& get(const pair<T2, T1>&) noexcept; // C++14

template<class T1, class T2>
    constexpr T1&& get(pair<T2, T1>&&) noexcept; // C++14

template<class T1, class T2>
    constexpr const T1&& get(const pair<T2, T1>&&) noexcept; // C++14

// C++14

template<class T, T... I>
struct integer_sequence
{
    typedef T value_type;

    static constexpr size_t size() noexcept;
};

template<size_t... I>
  using index_sequence = integer_sequence<size_t, I...>;

template<class T, T N>
  using make_integer_sequence = integer_sequence<T, 0, 1, ..., N-1>;
template<size_t N>
  using make_index_sequence = make_integer_sequence<size_t, N>;

template<class... T>
  using index_sequence_for = make_index_sequence<sizeof...(T)>;

template<class T, class U=T>
    constexpr T exchange(T& obj, U&& new_value)                                 // constexpr in C++17, noexcept in C++23
      noexcept(is_nothrow_move_constructible<T>::value && is_nothrow_assignable<T&, U>::value);

// 20.2.7, in-place construction // C++17
struct in_place_t {
  explicit in_place_t() = default;
};
inline constexpr in_place_t in_place{};
template <class T>
  struct in_place_type_t {
    explicit in_place_type_t() = default;
  };
template <class T>
  inline constexpr in_place_type_t<T> in_place_type{};
template <size_t I>
  struct in_place_index_t {
    explicit in_place_index_t() = default;
  };
template <size_t I>
  inline constexpr in_place_index_t<I> in_place_index{};

// [utility.underlying], to_underlying
template <class T>
    constexpr underlying_type_t<T> to_underlying( T value ) noexcept; // C++23

}  // std

*/

#if __cplusplus < 201103L && defined(_LIBCPP_USE_FROZEN_CXX03_HEADERS)
#  include <__cxx03/utility>
#else
#  include <__config>

#  include <__utility/declval.h>
#  include <__utility/forward.h>
#  include <__utility/move.h>
#  include <__utility/pair.h>
#  include <__utility/piecewise_construct.h>
#  include <__utility/rel_ops.h>
#  include <__utility/swap.h>

#  if _LIBCPP_STD_VER >= 14
#    include <__utility/exchange.h>
#    include <__utility/integer_sequence.h>
#  endif

#  if _LIBCPP_STD_VER >= 17
#    include <__utility/as_const.h>
#    include <__utility/in_place.h>
#  endif

#  if _LIBCPP_STD_VER >= 20
#    include <__utility/cmp.h>
#  endif

#  if _LIBCPP_STD_VER >= 23
#    include <__utility/forward_like.h>
#    include <__utility/to_underlying.h>
#    include <__utility/unreachable.h>
#  endif

#  include <version>

// standard-mandated includes

// [utility.syn]
#  include <compare>
#  include <initializer_list>

// [tuple.creation]

#  include <__tuple/ignore.h>

// [tuple.helper]
#  include <__tuple/tuple_element.h>
#  include <__tuple/tuple_size.h>

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

#  if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
#    include <limits>
#  endif

#  if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
#    include <cstddef>
#    include <cstdlib>
#    include <iosfwd>
#    include <type_traits>
#  endif
#endif // __cplusplus < 201103L && defined(_LIBCPP_USE_FROZEN_CXX03_HEADERS)

#endif // _LIBCPP_UTILITY