1 //===----------------------------------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 // UNSUPPORTED: c++98, c++03, c++11 10 // <utility> 11 12 // class make_integer_sequence 13 14 #include <tuple> 15 #include <utility> 16 #include <type_traits> 17 #include <cassert> 18 19 template <typename AtContainer, typename T, T... I> 20 auto extract ( const AtContainer &t, const std::integer_sequence<T, I...> ) 21 -> decltype ( std::make_tuple ( std::get<I>(t)... )) 22 { return std::make_tuple ( std::get<I>(t)... ); } 23 24 int main(int, char**) 25 { 26 // Make a couple of sequences 27 using int3 = std::make_integer_sequence<int, 3>; // generates int: 0,1,2 28 using size7 = std::make_integer_sequence<size_t, 7>; // generates size_t: 0,1,2,3,4,5,6 29 using size4 = std::make_index_sequence<4>; // generates size_t: 0,1,2,3 30 using size2 = std::index_sequence_for<int, size_t>; // generates size_t: 0,1 31 using intmix = std::integer_sequence<int, 9, 8, 7, 2>; // generates int: 9,8,7,2 32 using sizemix = std::index_sequence<1, 1, 2, 3, 5>; // generates size_t: 1,1,2,3,5 33 34 // Make sure they're what we expect 35 static_assert ( std::is_same<int3::value_type, int>::value, "int3 type wrong" ); 36 static_assert ( int3::size () == 3, "int3 size wrong" ); 37 38 static_assert ( std::is_same<size7::value_type, size_t>::value, "size7 type wrong" ); 39 static_assert ( size7::size () == 7, "size7 size wrong" ); 40 41 static_assert ( std::is_same<size4::value_type, size_t>::value, "size4 type wrong" ); 42 static_assert ( size4::size () == 4, "size4 size wrong" ); 43 44 static_assert ( std::is_same<size2::value_type, size_t>::value, "size2 type wrong" ); 45 static_assert ( size2::size () == 2, "size2 size wrong" ); 46 47 static_assert ( std::is_same<intmix::value_type, int>::value, "intmix type wrong" ); 48 static_assert ( intmix::size () == 4, "intmix size wrong" ); 49 50 static_assert ( std::is_same<sizemix::value_type, size_t>::value, "sizemix type wrong" ); 51 static_assert ( sizemix::size () == 5, "sizemix size wrong" ); 52 53 auto tup = std::make_tuple ( 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 ); 54 55 // Use them 56 auto t3 = extract ( tup, int3() ); 57 static_assert ( std::tuple_size<decltype(t3)>::value == int3::size (), "t3 size wrong"); 58 assert ( t3 == std::make_tuple ( 10, 11, 12 )); 59 60 auto t7 = extract ( tup, size7 ()); 61 static_assert ( std::tuple_size<decltype(t7)>::value == size7::size (), "t7 size wrong"); 62 assert ( t7 == std::make_tuple ( 10, 11, 12, 13, 14, 15, 16 )); 63 64 auto t4 = extract ( tup, size4 ()); 65 static_assert ( std::tuple_size<decltype(t4)>::value == size4::size (), "t4 size wrong"); 66 assert ( t4 == std::make_tuple ( 10, 11, 12, 13 )); 67 68 auto t2 = extract ( tup, size2 ()); 69 static_assert ( std::tuple_size<decltype(t2)>::value == size2::size (), "t2 size wrong"); 70 assert ( t2 == std::make_tuple ( 10, 11 )); 71 72 auto tintmix = extract ( tup, intmix ()); 73 static_assert ( std::tuple_size<decltype(tintmix)>::value == intmix::size (), "tintmix size wrong"); 74 assert ( tintmix == std::make_tuple ( 19, 18, 17, 12 )); 75 76 auto tsizemix = extract ( tup, sizemix ()); 77 static_assert ( std::tuple_size<decltype(tsizemix)>::value == sizemix::size (), "tsizemix size wrong"); 78 assert ( tsizemix == std::make_tuple ( 11, 11, 12, 13, 15 )); 79 80 return 0; 81 } 82