| // Pair implementation -*- C++ -*- |
| |
| // Copyright (C) 2001-2021 Free Software Foundation, Inc. |
| // |
| // This file is part of the GNU ISO C++ Library. This library is free |
| // software; you can redistribute it and/or modify it under the |
| // terms of the GNU General Public License as published by the |
| // Free Software Foundation; either version 3, or (at your option) |
| // any later version. |
| |
| // This library is distributed in the hope that it will be useful, |
| // but WITHOUT ANY WARRANTY; without even the implied warranty of |
| // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| // GNU General Public License for more details. |
| |
| // Under Section 7 of GPL version 3, you are granted additional |
| // permissions described in the GCC Runtime Library Exception, version |
| // 3.1, as published by the Free Software Foundation. |
| |
| // You should have received a copy of the GNU General Public License and |
| // a copy of the GCC Runtime Library Exception along with this program; |
| // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see |
| // <http://www.gnu.org/licenses/>. |
| |
| /* |
| * |
| * Copyright (c) 1994 |
| * Hewlett-Packard Company |
| * |
| * Permission to use, copy, modify, distribute and sell this software |
| * and its documentation for any purpose is hereby granted without fee, |
| * provided that the above copyright notice appear in all copies and |
| * that both that copyright notice and this permission notice appear |
| * in supporting documentation. Hewlett-Packard Company makes no |
| * representations about the suitability of this software for any |
| * purpose. It is provided "as is" without express or implied warranty. |
| * |
| * |
| * Copyright (c) 1996,1997 |
| * Silicon Graphics Computer Systems, Inc. |
| * |
| * Permission to use, copy, modify, distribute and sell this software |
| * and its documentation for any purpose is hereby granted without fee, |
| * provided that the above copyright notice appear in all copies and |
| * that both that copyright notice and this permission notice appear |
| * in supporting documentation. Silicon Graphics makes no |
| * representations about the suitability of this software for any |
| * purpose. It is provided "as is" without express or implied warranty. |
| */ |
| |
| /** @file bits/stl_pair.h |
| * This is an internal header file, included by other library headers. |
| * Do not attempt to use it directly. @headername{utility} |
| */ |
| |
| #ifndef _STL_PAIR_H |
| #define _STL_PAIR_H 1 |
| |
| #include <bits/move.h> // for std::move / std::forward, and std::swap |
| |
| #if __cplusplus >= 201103L |
| # include <type_traits> // for std::__decay_and_strip, std::is_reference_v |
| #endif |
| #if __cplusplus > 201703L |
| # include <compare> |
| # define __cpp_lib_constexpr_utility 201811L |
| #endif |
| |
| namespace std _GLIBCXX_VISIBILITY(default) |
| { |
| _GLIBCXX_BEGIN_NAMESPACE_VERSION |
| |
| /** |
| * @addtogroup utilities |
| * @{ |
| */ |
| |
| #if __cplusplus >= 201103L |
| /// Tag type for piecewise construction of std::pair objects. |
| struct piecewise_construct_t { explicit piecewise_construct_t() = default; }; |
| |
| /// Tag for piecewise construction of std::pair objects. |
| _GLIBCXX17_INLINE constexpr piecewise_construct_t piecewise_construct = |
| piecewise_construct_t(); |
| |
| /// @cond undocumented |
| |
| // Forward declarations. |
| template<typename...> |
| class tuple; |
| |
| template<size_t...> |
| struct _Index_tuple; |
| |
| // Concept utility functions, reused in conditionally-explicit |
| // constructors. |
| // See PR 70437, don't look at is_constructible or |
| // is_convertible if the types are the same to |
| // avoid querying those properties for incomplete types. |
| template <bool, typename _T1, typename _T2> |
| struct _PCC |
| { |
| template <typename _U1, typename _U2> |
| static constexpr bool _ConstructiblePair() |
| { |
| return __and_<is_constructible<_T1, const _U1&>, |
| is_constructible<_T2, const _U2&>>::value; |
| } |
| |
| template <typename _U1, typename _U2> |
| static constexpr bool _ImplicitlyConvertiblePair() |
| { |
| return __and_<is_convertible<const _U1&, _T1>, |
| is_convertible<const _U2&, _T2>>::value; |
| } |
| |
| template <typename _U1, typename _U2> |
| static constexpr bool _MoveConstructiblePair() |
| { |
| return __and_<is_constructible<_T1, _U1&&>, |
| is_constructible<_T2, _U2&&>>::value; |
| } |
| |
| template <typename _U1, typename _U2> |
| static constexpr bool _ImplicitlyMoveConvertiblePair() |
| { |
| return __and_<is_convertible<_U1&&, _T1>, |
| is_convertible<_U2&&, _T2>>::value; |
| } |
| |
| template <bool __implicit, typename _U1, typename _U2> |
| static constexpr bool _CopyMovePair() |
| { |
| using __do_converts = __and_<is_convertible<const _U1&, _T1>, |
| is_convertible<_U2&&, _T2>>; |
| using __converts = typename conditional<__implicit, |
| __do_converts, |
| __not_<__do_converts>>::type; |
| return __and_<is_constructible<_T1, const _U1&>, |
| is_constructible<_T2, _U2&&>, |
| __converts |
| >::value; |
| } |
| |
| template <bool __implicit, typename _U1, typename _U2> |
| static constexpr bool _MoveCopyPair() |
| { |
| using __do_converts = __and_<is_convertible<_U1&&, _T1>, |
| is_convertible<const _U2&, _T2>>; |
| using __converts = typename conditional<__implicit, |
| __do_converts, |
| __not_<__do_converts>>::type; |
| return __and_<is_constructible<_T1, _U1&&>, |
| is_constructible<_T2, const _U2&&>, |
| __converts |
| >::value; |
| } |
| }; |
| |
| template <typename _T1, typename _T2> |
| struct _PCC<false, _T1, _T2> |
| { |
| template <typename _U1, typename _U2> |
| static constexpr bool _ConstructiblePair() |
| { |
| return false; |
| } |
| |
| template <typename _U1, typename _U2> |
| static constexpr bool _ImplicitlyConvertiblePair() |
| { |
| return false; |
| } |
| |
| template <typename _U1, typename _U2> |
| static constexpr bool _MoveConstructiblePair() |
| { |
| return false; |
| } |
| |
| template <typename _U1, typename _U2> |
| static constexpr bool _ImplicitlyMoveConvertiblePair() |
| { |
| return false; |
| } |
| }; |
| #endif // C++11 |
| |
| template<typename _U1, typename _U2> class __pair_base |
| { |
| #if __cplusplus >= 201103L |
| template<typename _T1, typename _T2> friend struct pair; |
| __pair_base() = default; |
| ~__pair_base() = default; |
| __pair_base(const __pair_base&) = default; |
| __pair_base& operator=(const __pair_base&) = delete; |
| #endif // C++11 |
| }; |
| |
| /// @endcond |
| |
| /** |
| * @brief Struct holding two objects of arbitrary type. |
| * |
| * @tparam _T1 Type of first object. |
| * @tparam _T2 Type of second object. |
| * |
| * <https://gcc.gnu.org/onlinedocs/libstdc++/manual/utilities.html> |
| */ |
| template<typename _T1, typename _T2> |
| struct pair |
| : private __pair_base<_T1, _T2> |
| { |
| typedef _T1 first_type; ///< The type of the `first` member |
| typedef _T2 second_type; ///< The type of the `second` member |
| |
| _T1 first; ///< The first member |
| _T2 second; ///< The second member |
| |
| // _GLIBCXX_RESOLVE_LIB_DEFECTS |
| // 265. std::pair::pair() effects overly restrictive |
| /** The default constructor creates @c first and @c second using their |
| * respective default constructors. */ |
| #if __cplusplus >= 201103L |
| template <typename _U1 = _T1, |
| typename _U2 = _T2, |
| typename enable_if<__and_< |
| __is_implicitly_default_constructible<_U1>, |
| __is_implicitly_default_constructible<_U2>> |
| ::value, bool>::type = true> |
| #endif |
| _GLIBCXX_CONSTEXPR pair() |
| : first(), second() { } |
| |
| #if __cplusplus >= 201103L |
| template <typename _U1 = _T1, |
| typename _U2 = _T2, |
| typename enable_if<__and_< |
| is_default_constructible<_U1>, |
| is_default_constructible<_U2>, |
| __not_< |
| __and_<__is_implicitly_default_constructible<_U1>, |
| __is_implicitly_default_constructible<_U2>>>> |
| ::value, bool>::type = false> |
| explicit constexpr pair() |
| : first(), second() { } |
| #endif |
| |
| #if __cplusplus < 201103L |
| /// Two objects may be passed to a @c pair constructor to be copied. |
| pair(const _T1& __a, const _T2& __b) |
| : first(__a), second(__b) { } |
| #else |
| // Shortcut for constraining the templates that don't take pairs. |
| /// @cond undocumented |
| using _PCCP = _PCC<true, _T1, _T2>; |
| /// @endcond |
| |
| /// Construct from two const lvalues, allowing implicit conversions. |
| template<typename _U1 = _T1, typename _U2=_T2, typename |
| enable_if<_PCCP::template |
| _ConstructiblePair<_U1, _U2>() |
| && _PCCP::template |
| _ImplicitlyConvertiblePair<_U1, _U2>(), |
| bool>::type=true> |
| constexpr pair(const _T1& __a, const _T2& __b) |
| : first(__a), second(__b) { } |
| |
| /// Construct from two const lvalues, disallowing implicit conversions. |
| template<typename _U1 = _T1, typename _U2=_T2, typename |
| enable_if<_PCCP::template |
| _ConstructiblePair<_U1, _U2>() |
| && !_PCCP::template |
| _ImplicitlyConvertiblePair<_U1, _U2>(), |
| bool>::type=false> |
| explicit constexpr pair(const _T1& __a, const _T2& __b) |
| : first(__a), second(__b) { } |
| #endif |
| |
| #if __cplusplus < 201103L |
| /// There is also a templated constructor to convert from other pairs. |
| template<typename _U1, typename _U2> |
| pair(const pair<_U1, _U2>& __p) |
| : first(__p.first), second(__p.second) { } |
| #else |
| // Shortcut for constraining the templates that take pairs. |
| /// @cond undocumented |
| template <typename _U1, typename _U2> |
| using _PCCFP = _PCC<!is_same<_T1, _U1>::value |
| || !is_same<_T2, _U2>::value, |
| _T1, _T2>; |
| /// @endcond |
| |
| template<typename _U1, typename _U2, typename |
| enable_if<_PCCFP<_U1, _U2>::template |
| _ConstructiblePair<_U1, _U2>() |
| && _PCCFP<_U1, _U2>::template |
| _ImplicitlyConvertiblePair<_U1, _U2>(), |
| bool>::type=true> |
| constexpr pair(const pair<_U1, _U2>& __p) |
| : first(__p.first), second(__p.second) { } |
| |
| template<typename _U1, typename _U2, typename |
| enable_if<_PCCFP<_U1, _U2>::template |
| _ConstructiblePair<_U1, _U2>() |
| && !_PCCFP<_U1, _U2>::template |
| _ImplicitlyConvertiblePair<_U1, _U2>(), |
| bool>::type=false> |
| explicit constexpr pair(const pair<_U1, _U2>& __p) |
| : first(__p.first), second(__p.second) { } |
| #endif |
| |
| #if __cplusplus >= 201103L |
| constexpr pair(const pair&) = default; ///< Copy constructor |
| constexpr pair(pair&&) = default; ///< Move constructor |
| |
| // DR 811. |
| template<typename _U1, typename |
| enable_if<_PCCP::template |
| _MoveCopyPair<true, _U1, _T2>(), |
| bool>::type=true> |
| constexpr pair(_U1&& __x, const _T2& __y) |
| : first(std::forward<_U1>(__x)), second(__y) { } |
| |
| template<typename _U1, typename |
| enable_if<_PCCP::template |
| _MoveCopyPair<false, _U1, _T2>(), |
| bool>::type=false> |
| explicit constexpr pair(_U1&& __x, const _T2& __y) |
| : first(std::forward<_U1>(__x)), second(__y) { } |
| |
| template<typename _U2, typename |
| enable_if<_PCCP::template |
| _CopyMovePair<true, _T1, _U2>(), |
| bool>::type=true> |
| constexpr pair(const _T1& __x, _U2&& __y) |
| : first(__x), second(std::forward<_U2>(__y)) { } |
| |
| template<typename _U2, typename |
| enable_if<_PCCP::template |
| _CopyMovePair<false, _T1, _U2>(), |
| bool>::type=false> |
| explicit pair(const _T1& __x, _U2&& __y) |
| : first(__x), second(std::forward<_U2>(__y)) { } |
| |
| template<typename _U1, typename _U2, typename |
| enable_if<_PCCP::template |
| _MoveConstructiblePair<_U1, _U2>() |
| && _PCCP::template |
| _ImplicitlyMoveConvertiblePair<_U1, _U2>(), |
| bool>::type=true> |
| constexpr pair(_U1&& __x, _U2&& __y) |
| : first(std::forward<_U1>(__x)), second(std::forward<_U2>(__y)) { } |
| |
| template<typename _U1, typename _U2, typename |
| enable_if<_PCCP::template |
| _MoveConstructiblePair<_U1, _U2>() |
| && !_PCCP::template |
| _ImplicitlyMoveConvertiblePair<_U1, _U2>(), |
| bool>::type=false> |
| explicit constexpr pair(_U1&& __x, _U2&& __y) |
| : first(std::forward<_U1>(__x)), second(std::forward<_U2>(__y)) { } |
| |
| |
| template<typename _U1, typename _U2, typename |
| enable_if<_PCCFP<_U1, _U2>::template |
| _MoveConstructiblePair<_U1, _U2>() |
| && _PCCFP<_U1, _U2>::template |
| _ImplicitlyMoveConvertiblePair<_U1, _U2>(), |
| bool>::type=true> |
| constexpr pair(pair<_U1, _U2>&& __p) |
| : first(std::forward<_U1>(__p.first)), |
| second(std::forward<_U2>(__p.second)) { } |
| |
| template<typename _U1, typename _U2, typename |
| enable_if<_PCCFP<_U1, _U2>::template |
| _MoveConstructiblePair<_U1, _U2>() |
| && !_PCCFP<_U1, _U2>::template |
| _ImplicitlyMoveConvertiblePair<_U1, _U2>(), |
| bool>::type=false> |
| explicit constexpr pair(pair<_U1, _U2>&& __p) |
| : first(std::forward<_U1>(__p.first)), |
| second(std::forward<_U2>(__p.second)) { } |
| |
| template<typename... _Args1, typename... _Args2> |
| _GLIBCXX20_CONSTEXPR |
| pair(piecewise_construct_t, tuple<_Args1...>, tuple<_Args2...>); |
| |
| _GLIBCXX20_CONSTEXPR pair& |
| operator=(typename conditional< |
| __and_<is_copy_assignable<_T1>, |
| is_copy_assignable<_T2>>::value, |
| const pair&, const __nonesuch&>::type __p) |
| { |
| first = __p.first; |
| second = __p.second; |
| return *this; |
| } |
| |
| _GLIBCXX20_CONSTEXPR pair& |
| operator=(typename conditional< |
| __and_<is_move_assignable<_T1>, |
| is_move_assignable<_T2>>::value, |
| pair&&, __nonesuch&&>::type __p) |
| noexcept(__and_<is_nothrow_move_assignable<_T1>, |
| is_nothrow_move_assignable<_T2>>::value) |
| { |
| first = std::forward<first_type>(__p.first); |
| second = std::forward<second_type>(__p.second); |
| return *this; |
| } |
| |
| template<typename _U1, typename _U2> |
| _GLIBCXX20_CONSTEXPR |
| typename enable_if<__and_<is_assignable<_T1&, const _U1&>, |
| is_assignable<_T2&, const _U2&>>::value, |
| pair&>::type |
| operator=(const pair<_U1, _U2>& __p) |
| { |
| first = __p.first; |
| second = __p.second; |
| return *this; |
| } |
| |
| template<typename _U1, typename _U2> |
| _GLIBCXX20_CONSTEXPR |
| typename enable_if<__and_<is_assignable<_T1&, _U1&&>, |
| is_assignable<_T2&, _U2&&>>::value, |
| pair&>::type |
| operator=(pair<_U1, _U2>&& __p) |
| { |
| first = std::forward<_U1>(__p.first); |
| second = std::forward<_U2>(__p.second); |
| return *this; |
| } |
| |
| /// Swap the first members and then the second members. |
| _GLIBCXX20_CONSTEXPR void |
| swap(pair& __p) |
| noexcept(__and_<__is_nothrow_swappable<_T1>, |
| __is_nothrow_swappable<_T2>>::value) |
| { |
| using std::swap; |
| swap(first, __p.first); |
| swap(second, __p.second); |
| } |
| |
| private: |
| template<typename... _Args1, size_t... _Indexes1, |
| typename... _Args2, size_t... _Indexes2> |
| _GLIBCXX20_CONSTEXPR |
| pair(tuple<_Args1...>&, tuple<_Args2...>&, |
| _Index_tuple<_Indexes1...>, _Index_tuple<_Indexes2...>); |
| #endif // C++11 |
| }; |
| |
| /// @relates pair @{ |
| |
| #if __cpp_deduction_guides >= 201606 |
| template<typename _T1, typename _T2> pair(_T1, _T2) -> pair<_T1, _T2>; |
| #endif |
| |
| /// Two pairs of the same type are equal iff their members are equal. |
| template<typename _T1, typename _T2> |
| inline _GLIBCXX_CONSTEXPR bool |
| operator==(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) |
| { return __x.first == __y.first && __x.second == __y.second; } |
| |
| #if __cpp_lib_three_way_comparison && __cpp_lib_concepts |
| template<typename _T1, typename _T2> |
| constexpr common_comparison_category_t<__detail::__synth3way_t<_T1>, |
| __detail::__synth3way_t<_T2>> |
| operator<=>(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) |
| { |
| if (auto __c = __detail::__synth3way(__x.first, __y.first); __c != 0) |
| return __c; |
| return __detail::__synth3way(__x.second, __y.second); |
| } |
| #else |
| /** Defines a lexicographical order for pairs. |
| * |
| * For two pairs of the same type, `P` is ordered before `Q` if |
| * `P.first` is less than `Q.first`, or if `P.first` and `Q.first` |
| * are equivalent (neither is less than the other) and `P.second` is less |
| * than `Q.second`. |
| */ |
| template<typename _T1, typename _T2> |
| inline _GLIBCXX_CONSTEXPR bool |
| operator<(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) |
| { return __x.first < __y.first |
| || (!(__y.first < __x.first) && __x.second < __y.second); } |
| |
| /// Uses @c operator== to find the result. |
| template<typename _T1, typename _T2> |
| inline _GLIBCXX_CONSTEXPR bool |
| operator!=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) |
| { return !(__x == __y); } |
| |
| /// Uses @c operator< to find the result. |
| template<typename _T1, typename _T2> |
| inline _GLIBCXX_CONSTEXPR bool |
| operator>(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) |
| { return __y < __x; } |
| |
| /// Uses @c operator< to find the result. |
| template<typename _T1, typename _T2> |
| inline _GLIBCXX_CONSTEXPR bool |
| operator<=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) |
| { return !(__y < __x); } |
| |
| /// Uses @c operator< to find the result. |
| template<typename _T1, typename _T2> |
| inline _GLIBCXX_CONSTEXPR bool |
| operator>=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) |
| { return !(__x < __y); } |
| #endif // !(three_way_comparison && concepts) |
| |
| #if __cplusplus >= 201103L |
| /** Swap overload for pairs. Calls std::pair::swap(). |
| * |
| * @note This std::swap overload is not declared in C++03 mode, |
| * which has performance implications, e.g. see https://gcc.gnu.org/PR38466 |
| */ |
| template<typename _T1, typename _T2> |
| _GLIBCXX20_CONSTEXPR inline |
| #if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11 |
| // Constrained free swap overload, see p0185r1 |
| typename enable_if<__and_<__is_swappable<_T1>, |
| __is_swappable<_T2>>::value>::type |
| #else |
| void |
| #endif |
| swap(pair<_T1, _T2>& __x, pair<_T1, _T2>& __y) |
| noexcept(noexcept(__x.swap(__y))) |
| { __x.swap(__y); } |
| |
| #if __cplusplus > 201402L || !defined(__STRICT_ANSI__) // c++1z or gnu++11 |
| template<typename _T1, typename _T2> |
| typename enable_if<!__and_<__is_swappable<_T1>, |
| __is_swappable<_T2>>::value>::type |
| swap(pair<_T1, _T2>&, pair<_T1, _T2>&) = delete; |
| #endif |
| #endif // __cplusplus >= 201103L |
| |
| /// @} relates pair |
| |
| /** |
| * @brief A convenience wrapper for creating a pair from two objects. |
| * @param __x The first object. |
| * @param __y The second object. |
| * @return A newly-constructed pair<> object of the appropriate type. |
| * |
| * The C++98 standard says the objects are passed by reference-to-const, |
| * but C++03 says they are passed by value (this was LWG issue #181). |
| * |
| * Since C++11 they have been passed by forwarding reference and then |
| * forwarded to the new members of the pair. To create a pair with a |
| * member of reference type, pass a `reference_wrapper` to this function. |
| */ |
| // _GLIBCXX_RESOLVE_LIB_DEFECTS |
| // 181. make_pair() unintended behavior |
| #if __cplusplus >= 201103L |
| // NB: DR 706. |
| template<typename _T1, typename _T2> |
| constexpr pair<typename __decay_and_strip<_T1>::__type, |
| typename __decay_and_strip<_T2>::__type> |
| make_pair(_T1&& __x, _T2&& __y) |
| { |
| typedef typename __decay_and_strip<_T1>::__type __ds_type1; |
| typedef typename __decay_and_strip<_T2>::__type __ds_type2; |
| typedef pair<__ds_type1, __ds_type2> __pair_type; |
| return __pair_type(std::forward<_T1>(__x), std::forward<_T2>(__y)); |
| } |
| #else |
| template<typename _T1, typename _T2> |
| inline pair<_T1, _T2> |
| make_pair(_T1 __x, _T2 __y) |
| { return pair<_T1, _T2>(__x, __y); } |
| #endif |
| |
| /// @} |
| |
| _GLIBCXX_END_NAMESPACE_VERSION |
| } // namespace std |
| |
| #endif /* _STL_PAIR_H */ |
