// class template tuple -*- C++ -*- // Copyright (C) 2004-2020 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/>. /** @file tr1/tuple * This is a TR1 C++ Library header. */ // Chris Jefferson <chris@bubblescope.net> // Variadic Templates support by Douglas Gregor <doug.gregor@gmail.com> #ifndef _GLIBCXX_TR1_TUPLE #define _GLIBCXX_TR1_TUPLE 1 #pragma GCC system_header #include <utility> namespace std _GLIBCXX_VISIBILITY(default) { _GLIBCXX_BEGIN_NAMESPACE_VERSION namespace tr1 { // Adds a const reference to a non-reference type. template<typename _Tp> struct __add_c_ref { typedef const _Tp& type; }; template<typename _Tp> struct __add_c_ref<_Tp&> { typedef _Tp& type; }; // Adds a reference to a non-reference type. template<typename _Tp> struct __add_ref { typedef _Tp& type; }; template<typename _Tp> struct __add_ref<_Tp&> { typedef _Tp& type; }; /** * Contains the actual implementation of the @c tuple template, stored * as a recursive inheritance hierarchy from the first element (most * derived class) to the last (least derived class). The @c Idx * parameter gives the 0-based index of the element stored at this * point in the hierarchy; we use it to implement a constant-time * get() operation. */ template<int _Idx, typename... _Elements> struct _Tuple_impl; /** * Zero-element tuple implementation. This is the basis case for the * inheritance recursion. */ template<int _Idx> struct _Tuple_impl<_Idx> { }; /** * Recursive tuple implementation. Here we store the @c Head element * and derive from a @c Tuple_impl containing the remaining elements * (which contains the @c Tail). */ template<int _Idx, typename _Head, typename... _Tail> struct _Tuple_impl<_Idx, _Head, _Tail...> : public _Tuple_impl<_Idx + 1, _Tail...> { typedef _Tuple_impl<_Idx + 1, _Tail...> _Inherited; _Head _M_head; _Inherited& _M_tail() { return *this; } const _Inherited& _M_tail() const { return *this; } _Tuple_impl() : _Inherited(), _M_head() { } explicit _Tuple_impl(typename __add_c_ref<_Head>::type __head, typename __add_c_ref<_Tail>::type... __tail) : _Inherited(__tail...), _M_head(__head) { } template<typename... _UElements> _Tuple_impl(const _Tuple_impl<_Idx, _UElements...>& __in) : _Inherited(__in._M_tail()), _M_head(__in._M_head) { } _Tuple_impl(const _Tuple_impl& __in) : _Inherited(__in._M_tail()), _M_head(__in._M_head) { } template<typename... _UElements> _Tuple_impl& operator=(const _Tuple_impl<_Idx, _UElements...>& __in) { _M_head = __in._M_head; _M_tail() = __in._M_tail(); return *this; } _Tuple_impl& operator=(const _Tuple_impl& __in) { _M_head = __in._M_head; _M_tail() = __in._M_tail(); return *this; } }; template<typename... _Elements> class tuple : public _Tuple_impl<0, _Elements...> { typedef _Tuple_impl<0, _Elements...> _Inherited; public: tuple() : _Inherited() { } explicit tuple(typename __add_c_ref<_Elements>::type... __elements) : _Inherited(__elements...) { } template<typename... _UElements> tuple(const tuple<_UElements...>& __in) : _Inherited(__in) { } tuple(const tuple& __in) : _Inherited(__in) { } template<typename... _UElements> tuple& operator=(const tuple<_UElements...>& __in) { static_cast<_Inherited&>(*this) = __in; return *this; } tuple& operator=(const tuple& __in) { static_cast<_Inherited&>(*this) = __in; return *this; } }; template<> class tuple<> { }; // 2-element tuple, with construction and assignment from a pair. template<typename _T1, typename _T2> class tuple<_T1, _T2> : public _Tuple_impl<0, _T1, _T2> { typedef _Tuple_impl<0, _T1, _T2> _Inherited; public: tuple() : _Inherited() { } explicit tuple(typename __add_c_ref<_T1>::type __a1, typename __add_c_ref<_T2>::type __a2) : _Inherited(__a1, __a2) { } template<typename _U1, typename _U2> tuple(const tuple<_U1, _U2>& __in) : _Inherited(__in) { } tuple(const tuple& __in) : _Inherited(__in) { } template<typename _U1, typename _U2> tuple(const pair<_U1, _U2>& __in) : _Inherited(_Tuple_impl<0, typename __add_c_ref<_U1>::type, typename __add_c_ref<_U2>::type>(__in.first, __in.second)) { } template<typename _U1, typename _U2> tuple& operator=(const tuple<_U1, _U2>& __in) { static_cast<_Inherited&>(*this) = __in; return *this; } tuple& operator=(const tuple& __in) { static_cast<_Inherited&>(*this) = __in; return *this; } template<typename _U1, typename _U2> tuple& operator=(const pair<_U1, _U2>& __in) { this->_M_head = __in.first; this->_M_tail()._M_head = __in.second; return *this; } }; /// Gives the type of the ith element of a given tuple type. template<int __i, typename _Tp> struct tuple_element; /** * Recursive case for tuple_element: strip off the first element in * the tuple and retrieve the (i-1)th element of the remaining tuple. */ template<int __i, typename _Head, typename... _Tail> struct tuple_element<__i, tuple<_Head, _Tail...> > : tuple_element<__i - 1, tuple<_Tail...> > { }; /** * Basis case for tuple_element: The first element is the one we're seeking. */ template<typename _Head, typename... _Tail> struct tuple_element<0, tuple<_Head, _Tail...> > { typedef _Head type; }; /// Finds the size of a given tuple type. template<typename _Tp> struct tuple_size; /// class tuple_size template<typename... _Elements> struct tuple_size<tuple<_Elements...> > { static const int value = sizeof...(_Elements); }; template<typename... _Elements> const int tuple_size<tuple<_Elements...> >::value; template<int __i, typename _Head, typename... _Tail> inline typename __add_ref<_Head>::type __get_helper(_Tuple_impl<__i, _Head, _Tail...>& __t) { return __t._M_head; } template<int __i, typename _Head, typename... _Tail> inline typename __add_c_ref<_Head>::type __get_helper(const _Tuple_impl<__i, _Head, _Tail...>& __t) { return __t._M_head; } // Return a reference (const reference) to the ith element of a tuple. // Any const or non-const ref elements are returned with their original type. template<int __i, typename... _Elements> inline typename __add_ref< typename tuple_element<__i, tuple<_Elements...> >::type >::type get(tuple<_Elements...>& __t) { return __get_helper<__i>(__t); } template<int __i, typename... _Elements> inline typename __add_c_ref< typename tuple_element<__i, tuple<_Elements...> >::type >::type get(const tuple<_Elements...>& __t) { return __get_helper<__i>(__t); } // This class helps construct the various comparison operations on tuples template<int __check_equal_size, int __i, int __j, typename _Tp, typename _Up> struct __tuple_compare; template<int __i, int __j, typename _Tp, typename _Up> struct __tuple_compare<0, __i, __j, _Tp, _Up> { static bool __eq(const _Tp& __t, const _Up& __u) { return (get<__i>(__t) == get<__i>(__u) && __tuple_compare<0, __i+1, __j, _Tp, _Up>::__eq(__t, __u)); } static bool __less(const _Tp& __t, const _Up& __u) { return ((get<__i>(__t) < get<__i>(__u)) || !(get<__i>(__u) < get<__i>(__t)) && __tuple_compare<0, __i+1, __j, _Tp, _Up>::__less(__t, __u)); } }; template<int __i, typename _Tp, typename _Up> struct __tuple_compare<0, __i, __i, _Tp, _Up> { static bool __eq(const _Tp&, const _Up&) { return true; } static bool __less(const _Tp&, const _Up&) { return false; } }; template<typename... _TElements, typename... _UElements> bool operator==(const tuple<_TElements...>& __t, const tuple<_UElements...>& __u) { typedef tuple<_TElements...> _Tp; typedef tuple<_UElements...> _Up; return (__tuple_compare<tuple_size<_Tp>::value - tuple_size<_Up>::value, 0, tuple_size<_Tp>::value, _Tp, _Up>::__eq(__t, __u)); } template<typename... _TElements, typename... _UElements> bool operator<(const tuple<_TElements...>& __t, const tuple<_UElements...>& __u) { typedef tuple<_TElements...> _Tp; typedef tuple<_UElements...> _Up; return (__tuple_compare<tuple_size<_Tp>::value - tuple_size<_Up>::value, 0, tuple_size<_Tp>::value, _Tp, _Up>::__less(__t, __u)); } template<typename... _TElements, typename... _UElements> inline bool operator!=(const tuple<_TElements...>& __t, const tuple<_UElements...>& __u) { return !(__t == __u); } template<typename... _TElements, typename... _UElements> inline bool operator>(const tuple<_TElements...>& __t, const tuple<_UElements...>& __u) { return __u < __t; } template<typename... _TElements, typename... _UElements> inline bool operator<=(const tuple<_TElements...>& __t, const tuple<_UElements...>& __u) { return !(__u < __t); } template<typename... _TElements, typename... _UElements> inline bool operator>=(const tuple<_TElements...>& __t, const tuple<_UElements...>& __u) { return !(__t < __u); } template<typename _Tp> class reference_wrapper; // Helper which adds a reference to a type when given a reference_wrapper template<typename _Tp> struct __strip_reference_wrapper { typedef _Tp __type; }; template<typename _Tp> struct __strip_reference_wrapper<reference_wrapper<_Tp> > { typedef _Tp& __type; }; template<typename _Tp> struct __strip_reference_wrapper<const reference_wrapper<_Tp> > { typedef _Tp& __type; }; template<typename... _Elements> inline tuple<typename __strip_reference_wrapper<_Elements>::__type...> make_tuple(_Elements... __args) { typedef tuple<typename __strip_reference_wrapper<_Elements>::__type...> __result_type; return __result_type(__args...); } template<typename... _Elements> inline tuple<_Elements&...> tie(_Elements&... __args) { return tuple<_Elements&...>(__args...); } // A class (and instance) which can be used in 'tie' when an element // of a tuple is not required struct _Swallow_assign { template<class _Tp> _Swallow_assign& operator=(const _Tp&) { return *this; } }; // TODO: Put this in some kind of shared file. namespace { _Swallow_assign ignore; }; // anonymous namespace } _GLIBCXX_END_NAMESPACE_VERSION } #endif // _GLIBCXX_TR1_TUPLE