1 //////////////////////////////////////////////////////////////////////////////
2 //
3 // (C) Copyright Ion Gaztanaga 2008-2013. Distributed under the Boost
4 // Software License, Version 1.0. (See accompanying file
5 // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
6 //
7 // See http://www.boost.org/libs/container for documentation.
8 //
9 //////////////////////////////////////////////////////////////////////////////
10
11 #ifndef BOOST_CONTAINER_DETAIL_VARIADIC_TEMPLATES_TOOLS_HPP
12 #define BOOST_CONTAINER_DETAIL_VARIADIC_TEMPLATES_TOOLS_HPP
13
14 #ifndef BOOST_CONFIG_HPP
15 # include <boost/config.hpp>
16 #endif
17
18 #if defined(BOOST_HAS_PRAGMA_ONCE)
19 # pragma once
20 #endif
21
22 #include <boost/container/detail/config_begin.hpp>
23 #include <boost/container/detail/workaround.hpp>
24 #include <boost/move/utility_core.hpp>
25
26 #include <boost/container/detail/type_traits.hpp>
27 #include <cstddef> //std::size_t
28
29 namespace boost {
30 namespace container {
31 namespace container_detail {
32
33 template<typename... Values>
34 class tuple;
35
36 template<> class tuple<>
37 {};
38
39 template<typename Head, typename... Tail>
40 class tuple<Head, Tail...>
41 : private tuple<Tail...>
42 {
43 typedef tuple<Tail...> inherited;
44
45 public:
tuple()46 tuple()
47 : inherited(), m_head()
48 {}
49
50 template<class U, class ...Args>
tuple(U && u,Args &&...args)51 tuple(U &&u, Args && ...args)
52 : inherited(::boost::forward<Args>(args)...), m_head(::boost::forward<U>(u))
53 {}
54
55 // Construct tuple from another tuple.
56 template<typename... VValues>
tuple(const tuple<VValues...> & other)57 tuple(const tuple<VValues...>& other)
58 : inherited(other.tail()), m_head(other.head())
59 {}
60
61 template<typename... VValues>
operator =(const tuple<VValues...> & other)62 tuple& operator=(const tuple<VValues...>& other)
63 {
64 m_head = other.head();
65 tail() = other.tail();
66 return this;
67 }
68
head()69 typename add_reference<Head>::type head() { return m_head; }
head() const70 typename add_reference<const Head>::type head() const { return m_head; }
71
tail()72 inherited& tail() { return *this; }
tail() const73 const inherited& tail() const { return *this; }
74
75 protected:
76 Head m_head;
77 };
78
79
80 template<typename... Values>
forward_as_tuple(Values &&...values)81 tuple<Values&&...> forward_as_tuple(Values&&... values)
82 { return tuple<Values&&...>(::boost::forward<Values>(values)...); }
83
84 template<int I, typename Tuple>
85 struct tuple_element;
86
87 template<int I, typename Head, typename... Tail>
88 struct tuple_element<I, tuple<Head, Tail...> >
89 {
90 typedef typename tuple_element<I-1, tuple<Tail...> >::type type;
91 };
92
93 template<typename Head, typename... Tail>
94 struct tuple_element<0, tuple<Head, Tail...> >
95 {
96 typedef Head type;
97 };
98
99 template<int I, typename Tuple>
100 class get_impl;
101
102 template<int I, typename Head, typename... Values>
103 class get_impl<I, tuple<Head, Values...> >
104 {
105 typedef typename tuple_element<I-1, tuple<Values...> >::type Element;
106 typedef get_impl<I-1, tuple<Values...> > Next;
107
108 public:
109 typedef typename add_reference<Element>::type type;
110 typedef typename add_const_reference<Element>::type const_type;
get(tuple<Head,Values...> & t)111 static type get(tuple<Head, Values...>& t) { return Next::get(t.tail()); }
get(const tuple<Head,Values...> & t)112 static const_type get(const tuple<Head, Values...>& t) { return Next::get(t.tail()); }
113 };
114
115 template<typename Head, typename... Values>
116 class get_impl<0, tuple<Head, Values...> >
117 {
118 public:
119 typedef typename add_reference<Head>::type type;
120 typedef typename add_const_reference<Head>::type const_type;
get(tuple<Head,Values...> & t)121 static type get(tuple<Head, Values...>& t) { return t.head(); }
get(const tuple<Head,Values...> & t)122 static const_type get(const tuple<Head, Values...>& t){ return t.head(); }
123 };
124
125 template<int I, typename... Values>
get(tuple<Values...> & t)126 typename get_impl<I, tuple<Values...> >::type get(tuple<Values...>& t)
127 { return get_impl<I, tuple<Values...> >::get(t); }
128
129 template<int I, typename... Values>
get(const tuple<Values...> & t)130 typename get_impl<I, tuple<Values...> >::const_type get(const tuple<Values...>& t)
131 { return get_impl<I, tuple<Values...> >::get(t); }
132
133 ////////////////////////////////////////////////////
134 // Builds an index_tuple<0, 1, 2, ..., Num-1>, that will
135 // be used to "unpack" into comma-separated values
136 // in a function call.
137 ////////////////////////////////////////////////////
138
139 template<std::size_t...> struct index_tuple{ typedef index_tuple type; };
140
141 template<class S1, class S2> struct concat_index_tuple;
142
143 template<std::size_t... I1, std::size_t... I2>
144 struct concat_index_tuple<index_tuple<I1...>, index_tuple<I2...>>
145 : index_tuple<I1..., (sizeof...(I1)+I2)...>{};
146
147 template<std::size_t N> struct build_number_seq;
148
149 template<std::size_t N>
150 struct build_number_seq
151 : concat_index_tuple<typename build_number_seq<N/2>::type
152 ,typename build_number_seq<N - N/2 >::type
153 >::type
154 {};
155
156 template<> struct build_number_seq<0> : index_tuple<>{};
157 template<> struct build_number_seq<1> : index_tuple<0>{};
158
159 }}} //namespace boost { namespace container { namespace container_detail {
160
161 #include <boost/container/detail/config_end.hpp>
162
163 #endif //#ifndef BOOST_CONTAINER_DETAIL_VARIADIC_TEMPLATES_TOOLS_HPP
164