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
16namespace 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.
20template <typename T, T> struct SameType;
21
22namespace adl_detail {
23
24using std::begin;
25
26template <typename RangeT>
27constexpr auto begin_impl(RangeT &&range)
28 -> decltype(begin(std::forward<RangeT>(range))) {
29 return begin(std::forward<RangeT>(range));
30}
31
32using std::end;
33
34template <typename RangeT>
35constexpr auto end_impl(RangeT &&range)
36 -> decltype(end(std::forward<RangeT>(range))) {
37 return end(std::forward<RangeT>(range));
38}
39
40using std::rbegin;
41
42template <typename RangeT>
43constexpr auto rbegin_impl(RangeT &&range)
44 -> decltype(rbegin(std::forward<RangeT>(range))) {
45 return rbegin(std::forward<RangeT>(range));
46}
47
48using std::rend;
49
50template <typename RangeT>
51constexpr auto rend_impl(RangeT &&range)
52 -> decltype(rend(std::forward<RangeT>(range))) {
53 return rend(std::forward<RangeT>(range));
54}
55
56using std::swap;
57
58template <typename T>
59constexpr void swap_impl(T &&lhs,
60 T &&rhs) noexcept(noexcept(swap(std::declval<T>(),
61 std::declval<T>()))) {
62 swap(std::forward<T>(lhs), std::forward<T>(rhs));
63}
64
65using std::size;
66
67template <typename RangeT>
68constexpr auto size_impl(RangeT &&range)
69 -> decltype(size(std::forward<RangeT>(range))) {
70 return size(std::forward<RangeT>(range));
71}
72
73} // end namespace adl_detail
74
75/// Returns the begin iterator to \p range using `std::begin` and
76/// function found through Argument-Dependent Lookup (ADL).
77template <typename RangeT>
78constexpr auto adl_begin(RangeT &&range)
79 -> decltype(adl_detail::begin_impl(std::forward<RangeT>(range))) {
80 return adl_detail::begin_impl(std::forward<RangeT>(range));
81}
82
83/// Returns the end iterator to \p range using `std::end` and
84/// functions found through Argument-Dependent Lookup (ADL).
85template <typename RangeT>
86constexpr auto adl_end(RangeT &&range)
87 -> decltype(adl_detail::end_impl(std::forward<RangeT>(range))) {
88 return adl_detail::end_impl(std::forward<RangeT>(range));
89}
90
91/// Returns the reverse-begin iterator to \p range using `std::rbegin` and
92/// function found through Argument-Dependent Lookup (ADL).
93template <typename RangeT>
94constexpr auto adl_rbegin(RangeT &&range)
95 -> decltype(adl_detail::rbegin_impl(std::forward<RangeT>(range))) {
96 return adl_detail::rbegin_impl(std::forward<RangeT>(range));
97}
98
99/// Returns the reverse-end iterator to \p range using `std::rend` and
100/// functions found through Argument-Dependent Lookup (ADL).
101template <typename RangeT>
102constexpr auto adl_rend(RangeT &&range)
103 -> decltype(adl_detail::rend_impl(std::forward<RangeT>(range))) {
104 return adl_detail::rend_impl(std::forward<RangeT>(range));
105}
106
107/// Swaps \p lhs with \p rhs using `std::swap` and functions found through
108/// Argument-Dependent Lookup (ADL).
109template <typename T>
110constexpr void adl_swap(T &&lhs, T &&rhs) noexcept(
111 noexcept(adl_detail::swap_impl(std::declval<T>(), std::declval<T>()))) {
112 adl_detail::swap_impl(std::forward<T>(lhs), std::forward<T>(rhs));
113}
114
115/// Returns the size of \p range using `std::size` and functions found through
116/// Argument-Dependent Lookup (ADL).
117template <typename RangeT>
118constexpr auto adl_size(RangeT &&range)
119 -> decltype(adl_detail::size_impl(std::forward<RangeT>(range))) {
120 return adl_detail::size_impl(std::forward<RangeT>(range));
121}
122
123namespace detail {
124
125template <typename RangeT>
126using IterOfRange = decltype(adl_begin(std::declval<RangeT &>()));
127
128template <typename RangeT>
129using ValueOfRange =
130 std::remove_reference_t<decltype(*adl_begin(std::declval<RangeT &>()))>;
131
132} // namespace detail
133} // namespace llvm
134
135#endif // LLVM_ADT_ADL_H
136

source code of llvm/include/llvm/ADT/ADL.h