1 // Pair implementation -*- C++ -*-
3 // Copyright (C) 2001 Free Software Foundation, Inc.
5 // This file is part of the GNU ISO C++ Library. This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 2, or (at your option)
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
16 // You should have received a copy of the GNU General Public License along
17 // with this library; see the file COPYING. If not, write to the Free
18 // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
21 // As a special exception, you may use this file as part of a free software
22 // library without restriction. Specifically, if other files instantiate
23 // templates or use macros or inline functions from this file, or you compile
24 // this file and link it with other files to produce an executable, this
25 // file does not by itself cause the resulting executable to be covered by
26 // the GNU General Public License. This exception does not however
27 // invalidate any other reasons why the executable file might be covered by
28 // the GNU General Public License.
33 * Hewlett-Packard Company
35 * Permission to use, copy, modify, distribute and sell this software
36 * and its documentation for any purpose is hereby granted without fee,
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38 * that both that copyright notice and this permission notice appear
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41 * purpose. It is provided "as is" without express or implied warranty.
44 * Copyright (c) 1996,1997
45 * Silicon Graphics Computer Systems, Inc.
47 * Permission to use, copy, modify, distribute and sell this software
48 * and its documentation for any purpose is hereby granted without fee,
49 * provided that the above copyright notice appear in all copies and
50 * that both that copyright notice and this permission notice appear
51 * in supporting documentation. Silicon Graphics makes no
52 * representations about the suitability of this software for any
53 * purpose. It is provided "as is" without express or implied warranty.
57 * This is an internal header file, included by other library headers.
58 * You should not attempt to use it directly.
61 #ifndef __SGI_STL_INTERNAL_PAIR_H
62 #define __SGI_STL_INTERNAL_PAIR_H
67 /// pair holds two objects of arbitrary type.
68 template <class _T1, class _T2>
70 typedef _T1 first_type; ///< @c first_type is the first bound type
71 typedef _T2 second_type; ///< @c second_type is the second bound type
73 _T1 first; ///< @c first is a copy of the first object
74 _T2 second; ///< @c second is a copy of the second object
75 #ifdef _GLIBCPP_RESOLVE_LIB_DEFECTS
76 //265. std::pair::pair() effects overly restrictive
77 /** The default constructor creates @c first and @c second using their
78 * respective default constructors. */
79 pair() : first(), second() {}
81 pair() : first(_T1()), second(_T2()) {}
83 /** Two objects may be passed to a @c pair constructor to be copied. */
84 pair(const _T1& __a, const _T2& __b) : first(__a), second(__b) {}
86 /** There is also a templated copy ctor for the @c pair class itself. */
87 template <class _U1, class _U2>
88 pair(const pair<_U1, _U2>& __p) : first(__p.first), second(__p.second) {}
91 /// Two pairs of the same type are equal iff their members are equal.
92 template <class _T1, class _T2>
93 inline bool operator==(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
95 return __x.first == __y.first && __x.second == __y.second;
98 /// http://gcc.gnu.org/onlinedocs/libstdc++/20_util/howto.html#pairlt
99 template <class _T1, class _T2>
100 inline bool operator<(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
102 return __x.first < __y.first ||
103 (!(__y.first < __x.first) && __x.second < __y.second);
106 /// Uses @c operator== to find the result.
107 template <class _T1, class _T2>
108 inline bool operator!=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) {
109 return !(__x == __y);
112 /// Uses @c operator< to find the result.
113 template <class _T1, class _T2>
114 inline bool operator>(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) {
118 /// Uses @c operator< to find the result.
119 template <class _T1, class _T2>
120 inline bool operator<=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) {
124 /// Uses @c operator< to find the result.
125 template <class _T1, class _T2>
126 inline bool operator>=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y) {
131 * @brief A convenience wrapper for creating a pair from two objects.
132 * @param x The first object.
133 * @param y The second object.
134 * @return A newly-constructed pair<> object of the appropriate type.
136 * The standard requires that the objects be passed by reference-to-const,
137 * but LWG issue #181 says they should be passed by const value. We follow
138 * the LWG by default.
140 template <class _T1, class _T2>
141 #ifdef _GLIBCPP_RESOLVE_LIB_DEFECTS
142 //181. make_pair() unintended behavior
143 inline pair<_T1, _T2> make_pair(_T1 __x, _T2 __y)
145 inline pair<_T1, _T2> make_pair(const _T1& __x, const _T2& __y)
148 return pair<_T1, _T2>(__x, __y);
153 #endif /* __SGI_STL_INTERNAL_PAIR_H */