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// class template tuple -*- C++ -*-

// Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 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

// .

/** @file tr1/tuple

*  This is a TR1 C++ Library header.

*/

// Chris Jefferson 

// Variadic Templates support by Douglas Gregor 

#ifndef _GLIBCXX_TR1_TUPLE

#define _GLIBCXX_TR1_TUPLE 1

#pragma GCC system_header

#include 

namespace std _GLIBCXX_VISIBILITY(default)

{

namespace tr1

{

_GLIBCXX_BEGIN_NAMESPACE_VERSION

  // Adds a const reference to a non-reference type.

  template

    struct __add_c_ref

    { typedef const _Tp& type; };

  template

    struct __add_c_ref<_Tp&>

    { typedef _Tp& type; };

  // Adds a reference to a non-reference type.

  template

    struct __add_ref

    { typedef _Tp& type; };

  template

    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

    struct _Tuple_impl;

  /**

   * Zero-element tuple implementation. This is the basis case for the

   * inheritance recursion.

   */

  template

    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

    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

      _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

        _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

    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

        tuple(const tuple<_UElements...>& __in)

        : _Inherited(__in) { }

      tuple(const tuple& __in)

      : _Inherited(__in) { }

      template

        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

    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

        tuple(const tuple<_U1, _U2>& __in)

        : _Inherited(__in) { }

      tuple(const tuple& __in)

      : _Inherited(__in) { }

      template

        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

        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

        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

    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

    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

    struct tuple_element<0, tuple<_Head, _Tail...> >

    {

      typedef _Head type;

    };

  /// Finds the size of a given tuple type.

  template

    struct tuple_size;

  /// class tuple_size

  template

    struct tuple_size >

    {

      static const int value = sizeof...(_Elements);

    };

  template

    const int tuple_size >::value;

  template

    inline typename __add_ref<_Head>::type

    __get_helper(_Tuple_impl<__i, _Head, _Tail...>& __t)

    {

      return __t._M_head;

    }

  template

    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

    inline typename __add_ref<

                      typename tuple_element<__i, tuple<_Elements...> >::type

                    >::type

    get(tuple<_Elements...>& __t)

    {

      return __get_helper<__i>(__t);

    }

  template

    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

           typename _Tp, typename _Up>

    struct __tuple_compare;

  template

    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

    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

    bool

    operator==(const tuple<_TElements...>& __t,

               const tuple<_UElements...>& __u)

    {

      typedef tuple<_TElements...> _Tp;

      typedef tuple<_UElements...> _Up;

      return (__tuple_compare::value - tuple_size<_Up>::value,

              0, tuple_size<_Tp>::value, _Tp, _Up>::__eq(__t, __u));

    }

  template

    bool

    operator<(const tuple<_TElements...>& __t,

              const tuple<_UElements...>& __u)

    {

      typedef tuple<_TElements...> _Tp;

      typedef tuple<_UElements...> _Up;

      return (__tuple_compare::value - tuple_size<_Up>::value,

              0, tuple_size<_Tp>::value, _Tp, _Up>::__less(__t, __u));

    }

  template

    inline bool

    operator!=(const tuple<_TElements...>& __t,

               const tuple<_UElements...>& __u)

    { return !(__t == __u); }

  template

    inline bool

    operator>(const tuple<_TElements...>& __t,

              const tuple<_UElements...>& __u)

    { return __u < __t; }

  template

    inline bool

    operator<=(const tuple<_TElements...>& __t,

               const tuple<_UElements...>& __u)

    { return !(__u < __t); }

  template

    inline bool

    operator>=(const tuple<_TElements...>& __t,

               const tuple<_UElements...>& __u)

    { return !(__t < __u); }

  template

    class reference_wrapper;

  // Helper which adds a reference to a type when given a reference_wrapper

  template

    struct __strip_reference_wrapper

    {

      typedef _Tp __type;

    };

  template

    struct __strip_reference_wrapper >

    {

      typedef _Tp& __type;

    };

  template

    struct __strip_reference_wrapper >

    {

      typedef _Tp& __type;

    };

  template

    inline tuple::__type...>

    make_tuple(_Elements... __args)

    {

      typedef tuple::__type...>

        __result_type;

      return __result_type(__args...);

    }

  template

    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

      _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