stl_pair.h
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// Pair implementation -*- C++ -*-
// Copyright (C) 2001-2013 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 too
#endif
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
/**
* @addtogroup utilities
* @{
*/
#if __cplusplus >= 201103L
/// piecewise_construct_t
struct piecewise_construct_t { };
/// piecewise_construct
constexpr piecewise_construct_t piecewise_construct = piecewise_construct_t();
// Forward declarations.
template<typename...>
class tuple;
template<std::size_t...>
struct _Index_tuple;
#endif
/**
* @brief Struct holding two objects of arbitrary type.
*
* @tparam _T1 Type of first object.
* @tparam _T2 Type of second object.
*/
template<class _T1, class _T2>
struct pair
{
typedef _T1 first_type; /// @c first_type is the first bound type
typedef _T2 second_type; /// @c second_type is the second bound type
_T1 first; /// @c first is a copy of the first object
_T2 second; /// @c second is a copy of the second object
// _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. */
_GLIBCXX_CONSTEXPR pair()
: first(), second() { }
/** Two objects may be passed to a @c pair constructor to be copied. */
_GLIBCXX_CONSTEXPR pair(const _T1& __a, const _T2& __b)
: first(__a), second(__b) { }
/** There is also a templated copy ctor for the @c pair class itself. */
#if __cplusplus < 201103L
template<class _U1, class _U2>
pair(const pair<_U1, _U2>& __p)
: first(__p.first), second(__p.second) { }
#else
template<class _U1, class _U2, class = typename
enable_if<__and_<is_convertible<const _U1&, _T1>,
is_convertible<const _U2&, _T2>>::value>::type>
constexpr pair(const pair<_U1, _U2>& __p)
: first(__p.first), second(__p.second) { }
constexpr pair(const pair&) = default;
constexpr pair(pair&&) = default;
// DR 811.
template<class _U1, class = typename
enable_if<is_convertible<_U1, _T1>::value>::type>
constexpr pair(_U1&& __x, const _T2& __y)
: first(std::forward<_U1>(__x)), second(__y) { }
template<class _U2, class = typename
enable_if<is_convertible<_U2, _T2>::value>::type>
constexpr pair(const _T1& __x, _U2&& __y)
: first(__x), second(std::forward<_U2>(__y)) { }
template<class _U1, class _U2, class = typename
enable_if<__and_<is_convertible<_U1, _T1>,
is_convertible<_U2, _T2>>::value>::type>
constexpr pair(_U1&& __x, _U2&& __y)
: first(std::forward<_U1>(__x)), second(std::forward<_U2>(__y)) { }
template<class _U1, class _U2, class = typename
enable_if<__and_<is_convertible<_U1, _T1>,
is_convertible<_U2, _T2>>::value>::type>
constexpr pair(pair<_U1, _U2>&& __p)
: first(std::forward<_U1>(__p.first)),
second(std::forward<_U2>(__p.second)) { }
template<typename... _Args1, typename... _Args2>
pair(piecewise_construct_t, tuple<_Args1...>, tuple<_Args2...>);
pair&
operator=(const pair& __p)
{
first = __p.first;
second = __p.second;
return *this;
}
pair&
operator=(pair&& __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<class _U1, class _U2>
pair&
operator=(const pair<_U1, _U2>& __p)
{
first = __p.first;
second = __p.second;
return *this;
}
template<class _U1, class _U2>
pair&
operator=(pair<_U1, _U2>&& __p)
{
first = std::forward<_U1>(__p.first);
second = std::forward<_U2>(__p.second);
return *this;
}
void
swap(pair& __p)
noexcept(noexcept(swap(first, __p.first))
&& noexcept(swap(second, __p.second)))
{
using std::swap;
swap(first, __p.first);
swap(second, __p.second);
}
private:
template<typename... _Args1, std::size_t... _Indexes1,
typename... _Args2, std::size_t... _Indexes2>
pair(tuple<_Args1...>&, tuple<_Args2...>&,
_Index_tuple<_Indexes1...>, _Index_tuple<_Indexes2...>);
#endif
};
/// Two pairs of the same type are equal iff their members are equal.
template<class _T1, class _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; }
/// <http://gcc.gnu.org/onlinedocs/libstdc++/manual/utilities.html>
template<class _T1, class _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<class _T1, class _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<class _T1, class _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<class _T1, class _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<class _T1, class _T2>
inline _GLIBCXX_CONSTEXPR bool
operator>=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
{ return !(__x < __y); }
#if __cplusplus >= 201103L
/// See std::pair::swap().
// Note: no std::swap overloads in C++03 mode, this has performance
// implications, see, eg, libstdc++/38466.
template<class _T1, class _T2>
inline void
swap(pair<_T1, _T2>& __x, pair<_T1, _T2>& __y)
noexcept(noexcept(__x.swap(__y)))
{ __x.swap(__y); }
#endif
/**
* @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 standard requires that the objects be passed by reference-to-const,
* but LWG issue #181 says they should be passed by const value. We follow
* the LWG by default.
*/
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// 181. make_pair() unintended behavior
#if __cplusplus >= 201103L
// NB: DR 706.
template<class _T1, class _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<class _T1, class _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 */