1 //===- llvm/ADT/ADL.h - Argument dependent lookup utilities -----*- 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 #ifndef LLVM_ADT_ADL_H
10 #define LLVM_ADT_ADL_H
11
12 #include <type_traits>
13 #include <iterator>
14 #include <utility>
15
16 namespace llvm {
17
18 // Only used by compiler if both template types are the same. Useful when
19 // using SFINAE to test for the existence of member functions.
20 template <typename T, T> struct SameType;
21
22 namespace adl_detail {
23
24 using std::begin;
25
26 template <typename RangeT>
27 constexpr auto begin_impl(RangeT &&range)
28 -> decltype(begin(std::forward<RangeT>(range))) {
29 return begin(std::forward<RangeT>(range));
30 }
31
32 using std::end;
33
34 template <typename RangeT>
35 constexpr auto end_impl(RangeT &&range)
36 -> decltype(end(std::forward<RangeT>(range))) {
37 return end(std::forward<RangeT>(range));
38 }
39
40 using std::swap;
41
42 template <typename T>
swap_impl(T && lhs,T && rhs)43 constexpr void swap_impl(T &&lhs,
44 T &&rhs) noexcept(noexcept(swap(std::declval<T>(),
45 std::declval<T>()))) {
46 swap(std::forward<T>(lhs), std::forward<T>(rhs));
47 }
48
49 using std::size;
50
51 template <typename RangeT>
52 constexpr auto size_impl(RangeT &&range)
53 -> decltype(size(std::forward<RangeT>(range))) {
54 return size(std::forward<RangeT>(range));
55 }
56
57 } // end namespace adl_detail
58
59 /// Returns the begin iterator to \p range using `std::begin` and
60 /// function found through Argument-Dependent Lookup (ADL).
61 template <typename RangeT>
62 constexpr auto adl_begin(RangeT &&range)
63 -> decltype(adl_detail::begin_impl(std::forward<RangeT>(range))) {
64 return adl_detail::begin_impl(std::forward<RangeT>(range));
65 }
66
67 /// Returns the end iterator to \p range using `std::end` and
68 /// functions found through Argument-Dependent Lookup (ADL).
69 template <typename RangeT>
70 constexpr auto adl_end(RangeT &&range)
71 -> decltype(adl_detail::end_impl(std::forward<RangeT>(range))) {
72 return adl_detail::end_impl(std::forward<RangeT>(range));
73 }
74
75 /// Swaps \p lhs with \p rhs using `std::swap` and functions found through
76 /// Argument-Dependent Lookup (ADL).
77 template <typename T>
adl_swap(T && lhs,T && rhs)78 constexpr void adl_swap(T &&lhs, T &&rhs) noexcept(
79 noexcept(adl_detail::swap_impl(std::declval<T>(), std::declval<T>()))) {
80 adl_detail::swap_impl(std::forward<T>(lhs), std::forward<T>(rhs));
81 }
82
83 /// Returns the size of \p range using `std::size` and functions found through
84 /// Argument-Dependent Lookup (ADL).
85 template <typename RangeT>
86 constexpr auto adl_size(RangeT &&range)
87 -> decltype(adl_detail::size_impl(std::forward<RangeT>(range))) {
88 return adl_detail::size_impl(std::forward<RangeT>(range));
89 }
90
91 namespace detail {
92
93 template <typename RangeT>
94 using IterOfRange = decltype(adl_begin(std::declval<RangeT &>()));
95
96 template <typename RangeT>
97 using ValueOfRange =
98 std::remove_reference_t<decltype(*adl_begin(std::declval<RangeT &>()))>;
99
100 } // namespace detail
101 } // namespace llvm
102
103 #endif // LLVM_ADT_ADL_H
104