427 lines
12 KiB
C++
427 lines
12 KiB
C++
// class template tuple -*- C++ -*-
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// Copyright (C) 2004-2019 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 3, or (at your option)
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// any later version.
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// Under Section 7 of GPL version 3, you are granted additional
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// permissions described in the GCC Runtime Library Exception, version
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// 3.1, as published by the Free Software Foundation.
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// You should have received a copy of the GNU General Public License and
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// a copy of the GCC Runtime Library Exception along with this program;
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// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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// <http://www.gnu.org/licenses/>.
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/** @file tr1/tuple
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* This is a TR1 C++ Library header.
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*/
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// Chris Jefferson <chris@bubblescope.net>
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// Variadic Templates support by Douglas Gregor <doug.gregor@gmail.com>
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#ifndef _GLIBCXX_TR1_TUPLE
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#define _GLIBCXX_TR1_TUPLE 1
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#pragma GCC system_header
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#include <utility>
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namespace std _GLIBCXX_VISIBILITY(default)
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{
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_GLIBCXX_BEGIN_NAMESPACE_VERSION
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namespace tr1
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{
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// Adds a const reference to a non-reference type.
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template<typename _Tp>
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struct __add_c_ref
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{ typedef const _Tp& type; };
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template<typename _Tp>
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struct __add_c_ref<_Tp&>
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{ typedef _Tp& type; };
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// Adds a reference to a non-reference type.
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template<typename _Tp>
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struct __add_ref
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{ typedef _Tp& type; };
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template<typename _Tp>
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struct __add_ref<_Tp&>
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{ typedef _Tp& type; };
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/**
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* Contains the actual implementation of the @c tuple template, stored
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* as a recursive inheritance hierarchy from the first element (most
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* derived class) to the last (least derived class). The @c Idx
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* parameter gives the 0-based index of the element stored at this
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* point in the hierarchy; we use it to implement a constant-time
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* get() operation.
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*/
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template<int _Idx, typename... _Elements>
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struct _Tuple_impl;
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/**
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* Zero-element tuple implementation. This is the basis case for the
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* inheritance recursion.
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*/
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template<int _Idx>
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struct _Tuple_impl<_Idx> { };
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/**
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* Recursive tuple implementation. Here we store the @c Head element
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* and derive from a @c Tuple_impl containing the remaining elements
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* (which contains the @c Tail).
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*/
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template<int _Idx, typename _Head, typename... _Tail>
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struct _Tuple_impl<_Idx, _Head, _Tail...>
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: public _Tuple_impl<_Idx + 1, _Tail...>
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{
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typedef _Tuple_impl<_Idx + 1, _Tail...> _Inherited;
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_Head _M_head;
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_Inherited& _M_tail() { return *this; }
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const _Inherited& _M_tail() const { return *this; }
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_Tuple_impl() : _Inherited(), _M_head() { }
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explicit
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_Tuple_impl(typename __add_c_ref<_Head>::type __head,
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typename __add_c_ref<_Tail>::type... __tail)
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: _Inherited(__tail...), _M_head(__head) { }
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template<typename... _UElements>
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_Tuple_impl(const _Tuple_impl<_Idx, _UElements...>& __in)
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: _Inherited(__in._M_tail()), _M_head(__in._M_head) { }
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_Tuple_impl(const _Tuple_impl& __in)
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: _Inherited(__in._M_tail()), _M_head(__in._M_head) { }
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template<typename... _UElements>
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_Tuple_impl&
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operator=(const _Tuple_impl<_Idx, _UElements...>& __in)
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{
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_M_head = __in._M_head;
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_M_tail() = __in._M_tail();
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return *this;
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}
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_Tuple_impl&
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operator=(const _Tuple_impl& __in)
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{
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_M_head = __in._M_head;
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_M_tail() = __in._M_tail();
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return *this;
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}
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};
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template<typename... _Elements>
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class tuple : public _Tuple_impl<0, _Elements...>
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{
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typedef _Tuple_impl<0, _Elements...> _Inherited;
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public:
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tuple() : _Inherited() { }
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explicit
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tuple(typename __add_c_ref<_Elements>::type... __elements)
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: _Inherited(__elements...) { }
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template<typename... _UElements>
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tuple(const tuple<_UElements...>& __in)
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: _Inherited(__in) { }
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tuple(const tuple& __in)
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: _Inherited(__in) { }
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template<typename... _UElements>
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tuple&
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operator=(const tuple<_UElements...>& __in)
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{
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static_cast<_Inherited&>(*this) = __in;
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return *this;
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}
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tuple&
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operator=(const tuple& __in)
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{
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static_cast<_Inherited&>(*this) = __in;
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return *this;
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}
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};
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template<> class tuple<> { };
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// 2-element tuple, with construction and assignment from a pair.
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template<typename _T1, typename _T2>
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class tuple<_T1, _T2> : public _Tuple_impl<0, _T1, _T2>
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{
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typedef _Tuple_impl<0, _T1, _T2> _Inherited;
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public:
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tuple() : _Inherited() { }
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explicit
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tuple(typename __add_c_ref<_T1>::type __a1,
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typename __add_c_ref<_T2>::type __a2)
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: _Inherited(__a1, __a2) { }
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template<typename _U1, typename _U2>
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tuple(const tuple<_U1, _U2>& __in)
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: _Inherited(__in) { }
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tuple(const tuple& __in)
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: _Inherited(__in) { }
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template<typename _U1, typename _U2>
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tuple(const pair<_U1, _U2>& __in)
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: _Inherited(_Tuple_impl<0,
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typename __add_c_ref<_U1>::type,
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typename __add_c_ref<_U2>::type>(__in.first,
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__in.second))
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{ }
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template<typename _U1, typename _U2>
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tuple&
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operator=(const tuple<_U1, _U2>& __in)
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{
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static_cast<_Inherited&>(*this) = __in;
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return *this;
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}
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tuple&
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operator=(const tuple& __in)
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{
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static_cast<_Inherited&>(*this) = __in;
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return *this;
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}
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template<typename _U1, typename _U2>
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tuple&
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operator=(const pair<_U1, _U2>& __in)
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{
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this->_M_head = __in.first;
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this->_M_tail()._M_head = __in.second;
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return *this;
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}
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};
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/// Gives the type of the ith element of a given tuple type.
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template<int __i, typename _Tp>
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struct tuple_element;
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/**
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* Recursive case for tuple_element: strip off the first element in
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* the tuple and retrieve the (i-1)th element of the remaining tuple.
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*/
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template<int __i, typename _Head, typename... _Tail>
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struct tuple_element<__i, tuple<_Head, _Tail...> >
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: tuple_element<__i - 1, tuple<_Tail...> > { };
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/**
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* Basis case for tuple_element: The first element is the one we're seeking.
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*/
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template<typename _Head, typename... _Tail>
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struct tuple_element<0, tuple<_Head, _Tail...> >
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{
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typedef _Head type;
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};
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/// Finds the size of a given tuple type.
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template<typename _Tp>
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struct tuple_size;
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/// class tuple_size
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template<typename... _Elements>
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struct tuple_size<tuple<_Elements...> >
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{
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static const int value = sizeof...(_Elements);
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};
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template<typename... _Elements>
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const int tuple_size<tuple<_Elements...> >::value;
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template<int __i, typename _Head, typename... _Tail>
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inline typename __add_ref<_Head>::type
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__get_helper(_Tuple_impl<__i, _Head, _Tail...>& __t)
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{
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return __t._M_head;
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}
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template<int __i, typename _Head, typename... _Tail>
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inline typename __add_c_ref<_Head>::type
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__get_helper(const _Tuple_impl<__i, _Head, _Tail...>& __t)
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{
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return __t._M_head;
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}
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// Return a reference (const reference) to the ith element of a tuple.
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// Any const or non-const ref elements are returned with their original type.
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template<int __i, typename... _Elements>
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inline typename __add_ref<
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typename tuple_element<__i, tuple<_Elements...> >::type
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>::type
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get(tuple<_Elements...>& __t)
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{
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return __get_helper<__i>(__t);
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}
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template<int __i, typename... _Elements>
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inline typename __add_c_ref<
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typename tuple_element<__i, tuple<_Elements...> >::type
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>::type
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get(const tuple<_Elements...>& __t)
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{
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return __get_helper<__i>(__t);
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}
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// This class helps construct the various comparison operations on tuples
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template<int __check_equal_size, int __i, int __j,
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typename _Tp, typename _Up>
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struct __tuple_compare;
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template<int __i, int __j, typename _Tp, typename _Up>
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struct __tuple_compare<0, __i, __j, _Tp, _Up>
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{
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static bool __eq(const _Tp& __t, const _Up& __u)
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{
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return (get<__i>(__t) == get<__i>(__u) &&
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__tuple_compare<0, __i+1, __j, _Tp, _Up>::__eq(__t, __u));
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}
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static bool __less(const _Tp& __t, const _Up& __u)
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{
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return ((get<__i>(__t) < get<__i>(__u))
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|| !(get<__i>(__u) < get<__i>(__t)) &&
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__tuple_compare<0, __i+1, __j, _Tp, _Up>::__less(__t, __u));
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}
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};
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template<int __i, typename _Tp, typename _Up>
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struct __tuple_compare<0, __i, __i, _Tp, _Up>
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{
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static bool __eq(const _Tp&, const _Up&)
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{ return true; }
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static bool __less(const _Tp&, const _Up&)
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{ return false; }
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};
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template<typename... _TElements, typename... _UElements>
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bool
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operator==(const tuple<_TElements...>& __t,
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const tuple<_UElements...>& __u)
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{
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typedef tuple<_TElements...> _Tp;
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typedef tuple<_UElements...> _Up;
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return (__tuple_compare<tuple_size<_Tp>::value - tuple_size<_Up>::value,
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0, tuple_size<_Tp>::value, _Tp, _Up>::__eq(__t, __u));
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}
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template<typename... _TElements, typename... _UElements>
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bool
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operator<(const tuple<_TElements...>& __t,
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const tuple<_UElements...>& __u)
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{
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typedef tuple<_TElements...> _Tp;
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typedef tuple<_UElements...> _Up;
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return (__tuple_compare<tuple_size<_Tp>::value - tuple_size<_Up>::value,
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0, tuple_size<_Tp>::value, _Tp, _Up>::__less(__t, __u));
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}
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template<typename... _TElements, typename... _UElements>
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inline bool
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operator!=(const tuple<_TElements...>& __t,
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const tuple<_UElements...>& __u)
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{ return !(__t == __u); }
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template<typename... _TElements, typename... _UElements>
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inline bool
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operator>(const tuple<_TElements...>& __t,
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const tuple<_UElements...>& __u)
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{ return __u < __t; }
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template<typename... _TElements, typename... _UElements>
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inline bool
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operator<=(const tuple<_TElements...>& __t,
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const tuple<_UElements...>& __u)
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{ return !(__u < __t); }
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template<typename... _TElements, typename... _UElements>
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inline bool
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operator>=(const tuple<_TElements...>& __t,
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const tuple<_UElements...>& __u)
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{ return !(__t < __u); }
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template<typename _Tp>
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class reference_wrapper;
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// Helper which adds a reference to a type when given a reference_wrapper
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template<typename _Tp>
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struct __strip_reference_wrapper
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{
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typedef _Tp __type;
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};
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template<typename _Tp>
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struct __strip_reference_wrapper<reference_wrapper<_Tp> >
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{
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typedef _Tp& __type;
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};
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template<typename _Tp>
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struct __strip_reference_wrapper<const reference_wrapper<_Tp> >
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{
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typedef _Tp& __type;
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};
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template<typename... _Elements>
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inline tuple<typename __strip_reference_wrapper<_Elements>::__type...>
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make_tuple(_Elements... __args)
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{
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typedef tuple<typename __strip_reference_wrapper<_Elements>::__type...>
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__result_type;
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return __result_type(__args...);
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}
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template<typename... _Elements>
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inline tuple<_Elements&...>
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tie(_Elements&... __args)
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{
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return tuple<_Elements&...>(__args...);
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}
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// A class (and instance) which can be used in 'tie' when an element
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// of a tuple is not required
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struct _Swallow_assign
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{
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template<class _Tp>
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_Swallow_assign&
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operator=(const _Tp&)
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{ return *this; }
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};
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// TODO: Put this in some kind of shared file.
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namespace
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{
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_Swallow_assign ignore;
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}; // anonymous namespace
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}
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_GLIBCXX_END_NAMESPACE_VERSION
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}
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#endif // _GLIBCXX_TR1_TUPLE
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