MySQL 8.0.31
Source Code Documentation
ut0tuple.h
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27/** @file include/ut0tuple.h
28 std::tuple helper utilities. */
29
30#ifndef ut0tuple_h
31#define ut0tuple_h
32
33#include <tuple>
34#include <utility>
35
36// std::index_sequence can only generate a sequence of indices starting from 0.
37// This utility, index_sequence_with_offset, enables us to generate a
38// sequence of indices with the offset.
39//
40// E.g.
41// index_sequence_with_offset_t<10, std::make_index_sequence<5>{}>
42// generates a sequence of {10, 11, 12, 13, 14} integers.
43template <std::size_t N, typename Seq>
45
46template <std::size_t N, std::size_t... Ints>
47struct index_sequence_with_offset<N, std::index_sequence<Ints...>> {
48 using type = std::index_sequence<Ints + N...>;
49};
50
51// Helper alias which saves us from typing ::type
52template <std::size_t N, typename Seq>
55
56namespace detail {
57template <typename Tuple, size_t... Is>
58constexpr auto select_from_tuple_impl(Tuple &&t, std::index_sequence<Is...>) {
59 return std::make_tuple(std::get<Is>(t)...);
60}
61} // namespace detail
62
63// Utility function which returns a new tuple which is a [Begin, End> subset of
64// given tuple.
65// E.g.
66// auto t = select_from_tuple<1, 3>(make_tuple(1, 2, 3, 4, 5));
67// assert(t == make_tuple(2, 3));
68template <size_t Begin, size_t End, typename Tuple>
69constexpr auto select_from_tuple(Tuple &&t) {
71 std::forward<Tuple>(t),
73 std::make_index_sequence<End - Begin>>{});
74}
75
76#endif /* ut0tuple_h */
std::atomic< Type > N
Definition: ut0counter.h:224
Definition: ut0tuple.h:56
constexpr auto select_from_tuple_impl(Tuple &&t, std::index_sequence< Is... >)
Definition: ut0tuple.h:58
Definition: varlen_sort.h:183
std::index_sequence< Ints+N... > type
Definition: ut0tuple.h:48
Definition: ut0tuple.h:44
constexpr auto select_from_tuple(Tuple &&t)
Definition: ut0tuple.h:69
typename index_sequence_with_offset< N, Seq >::type index_sequence_with_offset_t
Definition: ut0tuple.h:54