1//
2// Copyright 2013 Francisco Jerez
3//
4// Permission is hereby granted, free of charge, to any person obtaining a
5// copy of this software and associated documentation files (the "Software"),
6// to deal in the Software without restriction, including without limitation
7// the rights to use, copy, modify, merge, publish, distribute, sublicense,
8// and/or sell copies of the Software, and to permit persons to whom the
9// Software is furnished to do so, subject to the following conditions:
10//
11// The above copyright notice and this permission notice shall be included in
12// all copies or substantial portions of the Software.
13//
14// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
17// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
18// OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
19// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
20// OTHER DEALINGS IN THE SOFTWARE.
21//
22
23#ifndef CLOVER_UTIL_TUPLE_HPP
24#define CLOVER_UTIL_TUPLE_HPP
25
26#include <tuple>
27
28namespace clover {
29   namespace tuple {
30      ///
31      /// Static sequence of integers.
32      ///
33      template<int... Is>
34      struct integral_sequence;
35
36      ///
37      /// Static sequence containing all integers from 0 to N-1.
38      ///
39      template<int N, int... Is>
40      struct enumerate {
41         typedef typename enumerate<N-1, N-1, Is...>::type
42            type;
43      };
44
45      template<int... Is>
46      struct enumerate<0, Is...> {
47         typedef integral_sequence<Is...> type;
48      };
49
50      namespace detail {
51         template<typename F, typename T,
52                  typename E = typename enumerate<std::tuple_size<
53                        typename std::remove_reference<T>::type>::value
54                     >::type>
55         struct _apply;
56
57         template<typename F, typename T, int... Is>
58         struct _apply<F, T, integral_sequence<Is...>> {
59            typedef typename std::remove_reference<F>::type func_type;
60            typedef decltype(
61               std::declval<func_type>()(std::get<Is>(std::declval<T &&>())...)
62               ) value_type;
63
64            static value_type
65               eval(F &&f, T &&t) {
66               return f(std::get<Is>(std::forward<T>(t))...);
67            }
68         };
69      }
70
71      ///
72      /// Evaluate function \a f with the elements of tuple \a t
73      /// expanded as arguments.
74      ///
75      template<typename F, typename T>
76      typename detail::_apply<F, T>::value_type
77      apply(F &&f, T &&t) {
78         return detail::_apply<F, T>::eval(std::forward<F>(f),
79                                           std::forward<T>(t));
80      }
81
82      namespace detail {
83         template<typename F, typename T,
84                  typename E = typename enumerate<std::tuple_size<
85                        typename std::remove_reference<T>::type>::value
86                     >::type>
87         struct _map;
88
89         template<typename F, typename T, int... Is>
90         struct _map<F, T, integral_sequence<Is...>> {
91            typedef typename std::remove_reference<F>::type func_type;
92            typedef std::tuple<
93               decltype(std::declval<func_type>()(
94                           std::get<Is>(std::declval<T &&>())))...
95               > value_type;
96
97            static value_type
98               eval(F &&f, T &&t) {
99               return value_type(f(std::get<Is>(std::forward<T>(t)))...);
100            }
101         };
102      }
103
104      ///
105      /// Evaluate function \a f on each element of the tuple \a t and
106      /// return the resulting values as a new tuple.
107      ///
108      template<typename F, typename T>
109      typename detail::_map<F, T>::value_type
110      map(F &&f, T &&t) {
111         return detail::_map<F, T>::eval(std::forward<F>(f),
112                                         std::forward<T>(t));
113      }
114   }
115}
116
117#endif
118