1// (C) Copyright John Maddock 2005.
2// Use, modification and distribution are subject to the
3// Boost Software License, Version 1.0. (See accompanying file
4// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
5
6#ifndef BOOST_TR1_UTILITY_HPP_INCLUDED
7# define BOOST_TR1_UTILITY_HPP_INCLUDED
8# include <boost/tr1/detail/config.hpp>
9
10#ifdef BOOST_HAS_TR1_UTILITY
11
12# if defined(BOOST_HAS_INCLUDE_NEXT) && !defined(BOOST_TR1_DISABLE_INCLUDE_NEXT)
13# include_next BOOST_TR1_HEADER(utility)
14# else
15# include <boost/tr1/detail/config_all.hpp>
16# include BOOST_TR1_STD_HEADER(BOOST_TR1_PATH(utility))
17# endif
18
19#else
20
21#if defined(BOOST_TR1_USE_OLD_TUPLE)
22
23#include <boost/type_traits/integral_constant.hpp>
24#include <boost/type_traits/add_const.hpp>
25#include <boost/type_traits/add_reference.hpp>
26#include <boost/mpl/if.hpp>
27
28
29namespace std{ namespace tr1{
30
31template <class T> struct tuple_size; // forward declaration
32template < int I, class T> struct tuple_element; // forward declaration
33
34template <class T1, class T2>
35struct tuple_size< ::std::pair<T1, T2> >
36 : public ::boost::integral_constant< ::std::size_t, 2>
37{
38};
39
40template <class T1, class T2>
41struct tuple_element<0, ::std::pair<T1, T2> >
42{
43 typedef typename std::pair<T1, T2>::first_type type;
44};
45
46template <class T1, class T2>
47struct tuple_element<1, std::pair<T1, T2> >
48{
49 typedef typename std::pair<T1, T2>::second_type type;
50};
51
52namespace tuple_detail{
53 template <int I, class T1, class T2>
54 struct tuple_get_result
55 {
56 typedef typename boost::mpl::if_c<I==0, T1, T2>::type t1;
57 typedef typename boost::add_reference<t1>::type type;
58 };
59 template <int I, class T1, class T2>
60 struct const_tuple_get_result
61 {
62 typedef typename boost::mpl::if_c<I==0, T1, T2>::type t1;
63# if BOOST_WORKAROUND( __BORLANDC__, BOOST_TESTED_AT( 0x582))
64 // I have absolutely no idea why add_const is not working here for Borland!
65 // It passes all other free-standing tests, some strange interaction going on
66 typedef typename boost::add_reference< const t1 >::type type;
67# else
68 typedef typename boost::add_const<t1>::type t2;
69 typedef typename boost::add_reference<t2>::type type;
70# endif
71 };
72
73template<int I, class T1, class T2>
74inline typename tuple_detail::tuple_get_result<I,T1,T2>::type get(std::pair<T1, T2>& p, const ::boost::true_type&)
75{
76 return p.first;
77}
78
79template<int I, class T1, class T2>
80inline typename tuple_detail::const_tuple_get_result<I,T1,T2>::type get(const std::pair<T1, T2>& p, const ::boost::true_type&)
81{
82 return p.first;
83}
84
85template<int I, class T1, class T2>
86inline typename tuple_detail::tuple_get_result<I,T1,T2>::type get(std::pair<T1, T2>& p, const ::boost::false_type&)
87{
88 return p.second;
89}
90
91template<int I, class T1, class T2>
92inline typename tuple_detail::const_tuple_get_result<I,T1,T2>::type get(const std::pair<T1, T2>& p, const ::boost::false_type&)
93{
94 return p.second;
95}
96
97}
98
99template<int I, class T1, class T2>
100inline typename tuple_detail::tuple_get_result<I,T1,T2>::type get(std::pair<T1, T2>& p)
101{
102 return tuple_detail::get<I>(p, boost::integral_constant<bool, I==0>());
103}
104
105template<int I, class T1, class T2>
106inline typename tuple_detail::const_tuple_get_result<I,T1,T2>::type get(const std::pair<T1, T2>& p)
107{
108 return tuple_detail::get<I>(p, boost::integral_constant<bool, I==0>());
109}
110
111} } // namespaces
112
113#else
114
115#include <boost/tr1/tuple.hpp>
116
117#endif
118
119#endif
120
121#endif
122

source code of boost/boost/tr1/utility.hpp