8877b5a9bd
2009-01-07 Paolo Carlini <paolo.carlini@oracle.com> PR libstdc++/38466 * include/bits/stl_pair.h: Document C++03 pair vs swap. From-SVN: r143154
267 lines
8.6 KiB
C++
267 lines
8.6 KiB
C++
// Pair implementation -*- C++ -*-
|
|
|
|
// Copyright (C) 2001, 2002, 2003, 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 2, 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.
|
|
|
|
// You should have received a copy of the GNU General Public License along
|
|
// with this library; see the file COPYING. If not, write to the Free
|
|
// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
|
|
// USA.
|
|
|
|
// As a special exception, you may use this file as part of a free software
|
|
// library without restriction. Specifically, if other files instantiate
|
|
// templates or use macros or inline functions from this file, or you compile
|
|
// this file and link it with other files to produce an executable, this
|
|
// file does not by itself cause the resulting executable to be covered by
|
|
// the GNU General Public License. This exception does not however
|
|
// invalidate any other reasons why the executable file might be covered by
|
|
// the GNU General Public License.
|
|
|
|
/*
|
|
*
|
|
* 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 stl_pair.h
|
|
* This is an internal header file, included by other library headers.
|
|
* You should not attempt to use it directly.
|
|
*/
|
|
|
|
#ifndef _STL_PAIR_H
|
|
#define _STL_PAIR_H 1
|
|
|
|
#include <bits/move.h> // for std::move / std::forward, std::decay, and
|
|
// std::swap
|
|
|
|
_GLIBCXX_BEGIN_NAMESPACE(std)
|
|
|
|
/// pair holds two objects of arbitrary type.
|
|
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. */
|
|
pair()
|
|
: first(), second() { }
|
|
|
|
/** Two objects may be passed to a @c pair constructor to be copied. */
|
|
pair(const _T1& __a, const _T2& __b)
|
|
: first(__a), second(__b) { }
|
|
|
|
#ifdef __GXX_EXPERIMENTAL_CXX0X__
|
|
template<class _U1, class _U2>
|
|
pair(_U1&& __x, _U2&& __y)
|
|
: first(std::forward<_U1>(__x)),
|
|
second(std::forward<_U2>(__y)) { }
|
|
|
|
pair(pair&& __p)
|
|
: first(std::move(__p.first)),
|
|
second(std::move(__p.second)) { }
|
|
#endif
|
|
|
|
/** There is also a templated copy ctor for the @c pair class itself. */
|
|
template<class _U1, class _U2>
|
|
pair(const pair<_U1, _U2>& __p)
|
|
: first(__p.first),
|
|
second(__p.second) { }
|
|
|
|
#ifdef __GXX_EXPERIMENTAL_CXX0X__
|
|
template<class _U1, class _U2>
|
|
pair(pair<_U1, _U2>&& __p)
|
|
: first(std::move(__p.first)),
|
|
second(std::move(__p.second)) { }
|
|
|
|
// http://gcc.gnu.org/ml/libstdc++/2007-08/msg00052.html
|
|
template<class _U1, class _Arg0, class... _Args>
|
|
pair(_U1&& __x, _Arg0&& __arg0, _Args&&... __args)
|
|
: first(std::forward<_U1>(__x)),
|
|
second(std::forward<_Arg0>(__arg0),
|
|
std::forward<_Args>(__args)...) { }
|
|
|
|
pair&
|
|
operator=(pair&& __p)
|
|
{
|
|
first = std::move(__p.first);
|
|
second = std::move(__p.second);
|
|
return *this;
|
|
}
|
|
|
|
template<class _U1, class _U2>
|
|
pair&
|
|
operator=(pair<_U1, _U2>&& __p)
|
|
{
|
|
first = std::move(__p.first);
|
|
second = std::move(__p.second);
|
|
return *this;
|
|
}
|
|
|
|
void
|
|
swap(pair&& __p)
|
|
{
|
|
using std::swap;
|
|
swap(first, __p.first);
|
|
swap(second, __p.second);
|
|
}
|
|
#endif
|
|
};
|
|
|
|
/// Two pairs of the same type are equal iff their members are equal.
|
|
template<class _T1, class _T2>
|
|
inline 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 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 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 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 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 bool
|
|
operator>=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
|
|
{ return !(__x < __y); }
|
|
|
|
#ifdef __GXX_EXPERIMENTAL_CXX0X__
|
|
/// 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)
|
|
{ __x.swap(__y); }
|
|
|
|
template<class _T1, class _T2>
|
|
inline void
|
|
swap(pair<_T1, _T2>&& __x, pair<_T1, _T2>& __y)
|
|
{ __x.swap(__y); }
|
|
|
|
template<class _T1, class _T2>
|
|
inline void
|
|
swap(pair<_T1, _T2>& __x, pair<_T1, _T2>&& __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
|
|
#ifndef __GXX_EXPERIMENTAL_CXX0X__
|
|
template<class _T1, class _T2>
|
|
inline pair<_T1, _T2>
|
|
make_pair(_T1 __x, _T2 __y)
|
|
{ return pair<_T1, _T2>(__x, __y); }
|
|
#else
|
|
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 _Tp>
|
|
struct __decay_and_strip
|
|
{
|
|
typedef typename __strip_reference_wrapper<
|
|
typename decay<_Tp>::type>::__type __type;
|
|
};
|
|
|
|
// NB: DR 706.
|
|
template<class _T1, class _T2>
|
|
inline pair<typename __decay_and_strip<_T1>::__type,
|
|
typename __decay_and_strip<_T2>::__type>
|
|
make_pair(_T1&& __x, _T2&& __y)
|
|
{
|
|
return pair<typename __decay_and_strip<_T1>::__type,
|
|
typename __decay_and_strip<_T2>::__type>
|
|
(std::forward<_T1>(__x), std::forward<_T2>(__y));
|
|
}
|
|
#endif
|
|
|
|
_GLIBCXX_END_NAMESPACE
|
|
|
|
#endif /* _STL_PAIR_H */
|