1 //===-------- stl_extras.h - Useful STL related functions-------*- C++ -*-===//
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 // This file is a part of the ORC runtime support library.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef ORC_RT_STL_EXTRAS_H
14 #define ORC_RT_STL_EXTRAS_H
15 
16 #include <utility>
17 #include <tuple>
18 
19 namespace __orc_rt {
20 
21 namespace detail {
22 
23 template <typename F, typename Tuple, std::size_t... I>
24 decltype(auto) apply_tuple_impl(F &&f, Tuple &&t, std::index_sequence<I...>) {
25   return std::forward<F>(f)(std::get<I>(std::forward<Tuple>(t))...);
26 }
27 
28 } // end namespace detail
29 
30 /// Given an input tuple (a1, a2, ..., an), pass the arguments of the
31 /// tuple variadically to f as if by calling f(a1, a2, ..., an) and
32 /// return the result.
33 ///
34 /// FIXME: Switch to std::apply once we can use c++17.
35 template <typename F, typename Tuple>
36 decltype(auto) apply_tuple(F &&f, Tuple &&t) {
37   using Indices = std::make_index_sequence<
38       std::tuple_size<typename std::decay<Tuple>::type>::value>;
39 
40   return detail::apply_tuple_impl(std::forward<F>(f), std::forward<Tuple>(t),
41                                   Indices{});
42 }
43 
44 } // namespace __orc_rt
45 
46 #endif // ORC_RT_STL_EXTRAS
47