1 /* Copyright (c) 2016. The SimGrid Team.
2 * All rights reserved. */
4 /* This program is free software; you can redistribute it and/or modify it
5 * under the terms of the license (GNU LGPL) which comes with this package. */
12 // integer_sequence and friends from C++14
13 // We need them to implement `apply` from C++17.
15 /** A compile-time sequence of integers (from C++14)
17 * `index_sequence<std::size_t,1,5,7,9>` represents the sequence `(1,5,7,9)`.
20 * template<class T, std::size_t... I>
21 * auto extract_tuple(T&& t, integer_sequence<std::size_t, I...>)
22 * -> decltype(std::make_tuple(std::get<I>(std::forward<T>(t))...))
24 * return std::make_tuple(std::get<I>(std::forward<T>(t))...);
29 * integer_sequence<std::size_t, 1, 3> seq;
30 * auto a = std::make_tuple(1, 2.0, false, 'a');
31 * auto b = extract_tuple(a, seq);
32 * std::cout << std::get<0>(b) << '\n'; // 2
33 * std::cout << std::get<1>(b) << '\n'; // a
38 template<class T, T... N>
39 class integer_sequence {
40 static constexpr std::size_t size()
42 return std::tuple_size<decltype(std::make_tuple(N...))>::value;
47 template<class T, long long N, long long... M>
48 struct make_integer_sequence :
49 make_integer_sequence<T, N-1, N-1, M...>
51 template<class T, long long... M>
52 struct make_integer_sequence<T, 0, M...> {
53 typedef integer_sequence<T, (T) M...> type;
57 /** A compile-time sequence of integers of the form `(0,1,2,3,...,N-1)` (from C++14) */
58 template<class T, T N>
59 using make_integer_sequence = typename simgrid::xbt::bits::make_integer_sequence<T,N>::type;
61 /** A compile-time sequence of indices (from C++14) */
62 template<std::size_t... Ints>
63 using index_sequence = integer_sequence<std::size_t, Ints...>;
65 /** A compile-time sequence of indices of the form `(0,1,2,3,...,N-1)` (from C++14) */
66 template<std::size_t N>
67 using make_index_sequence = make_integer_sequence<std::size_t, N>;
69 /** Convert a type parameter pack into a index_sequence (from C++14) */
71 using index_sequence_for = make_index_sequence<sizeof...(T)>;
73 static_assert(std::is_same< make_index_sequence<0>, index_sequence<> >::value, "seq0");
74 static_assert(std::is_same< make_index_sequence<1>, index_sequence<0> >::value, "seq1");
75 static_assert(std::is_same< make_index_sequence<2>, index_sequence<0, 1> >::value, "seq2");
76 static_assert(std::is_same< make_index_sequence<3>, index_sequence<0, 1, 2> >::value, "seq3");
77 static_assert(std::is_same< index_sequence_for<int,double,float>, make_index_sequence<3> >::value, "seq4");