L4Re - L4 Runtime Environment
pair
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1 // vi:set ft=cpp: -*- Mode: C++ -*-
2 /**
3  * \file
4  * \brief Pair implementation
5  */
6 /*
7  * (c) 2008-2009 Alexander Warg <warg@os.inf.tu-dresden.de>
8  * economic rights: Technische Universit├Ąt Dresden (Germany)
9  *
10  * This file is part of TUD:OS and distributed under the terms of the
11  * GNU General Public License 2.
12  * Please see the COPYING-GPL-2 file for details.
13  *
14  * As a special exception, you may use this file as part of a free software
15  * library without restriction. Specifically, if other files instantiate
16  * templates or use macros or inline functions from this file, or you compile
17  * this file and link it with other files to produce an executable, this
18  * file does not by itself cause the resulting executable to be covered by
19  * the GNU General Public License. This exception does not however
20  * invalidate any other reasons why the executable file might be covered by
21  * the GNU General Public License.
22  */
23 #pragma once
24 
25 namespace cxx {
26 
27 /**
28  * \ingroup cxx_api
29  * \brief Pair of two values.
30  *
31  * Standard container for a pair of values.
32  * \param First Type of the first value.
33  * \param Second Type of the second value.
34  */
35 template< typename First, typename Second >
36 struct Pair
37 {
38  /// Type of first value.
39  typedef First First_type;
40  /// Type of second value.
41  typedef Second Second_type;
42 
43  /// First value.
44  First first;
45  /// Second value.
46  Second second;
47 
48  /**
49  * \brief Create a pair from the two values.
50  * \param first The first value.
51  * \param second The second value.
52  */
53  template<typename A1, typename A2>
54  Pair(A1 &&first, A2 &&second)
55  : first(first), second(second) {}
56 
57  /// Default construction.
58  Pair() {}
59 };
60 
61 template< typename F, typename S >
62 Pair<F,S> pair(F const &f, S const &s)
63 { return cxx::Pair<F,S>(f,s); }
64 
65 
66 /**
67  * \brief Comparison functor for Pair.
68  * \param Cmp Comparison functor for the first value of the pair.
69  * \param Typ The pair type.
70  *
71  * This functor can be used to compare Pair values with respect to the
72  * first value.
73  */
74 template< typename Cmp, typename Typ >
75 class Pair_first_compare
76 {
77 private:
78  Cmp const &_cmp;
79 
80 public:
81  /**
82  * \brief Construction.
83  * \param cmp The comparison functor used for the first value.
84  */
85  Pair_first_compare(Cmp const &cmp = Cmp()) : _cmp(cmp) {}
86 
87  /**
88  * \brief Do the comaprison based on the first value.
89  * \param l The lefthand value.
90  * \param r The righthand value.
91  */
92  bool operator () (Typ const &l, Typ const &r) const
93  { return _cmp(l.first,r.first); }
94 };
95 
96 }
97 
98 template< typename OS, typename A, typename B >
99 inline
100 OS &operator << (OS &os, cxx::Pair<A,B> const &p)
101 {
102  os << p.first << ';' << p.second;
103  return os;
104 }
105