1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
|
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// UNSUPPORTED: c++98, c++03, c++11, c++14
// <tuple>
// template <class T, class Tuple> constexpr T make_from_tuple(Tuple&&);
#include <tuple>
#include <array>
#include <utility>
#include <string>
#include <cassert>
#include "test_macros.h"
#include "type_id.h"
// std::array is explicitly allowed to be initialized with A a = { init-list };.
// Disable the missing braces warning for this reason.
#include "disable_missing_braces_warning.h"
template <class Tuple>
struct ConstexprConstructibleFromTuple {
template <class ...Args>
explicit constexpr ConstexprConstructibleFromTuple(Args&&... xargs)
: args{std::forward<Args>(xargs)...} {}
Tuple args;
};
template <class TupleLike>
struct ConstructibleFromTuple;
template <template <class ...> class Tuple, class ...Types>
struct ConstructibleFromTuple<Tuple<Types...>> {
template <class ...Args>
explicit ConstructibleFromTuple(Args&&... xargs)
: args(xargs...),
arg_types(&makeArgumentID<Args&&...>())
{}
Tuple<std::decay_t<Types>...> args;
TypeID const* arg_types;
};
template <class Tp, size_t N>
struct ConstructibleFromTuple<std::array<Tp, N>> {
template <class ...Args>
explicit ConstructibleFromTuple(Args&&... xargs)
: args{xargs...},
arg_types(&makeArgumentID<Args&&...>())
{}
std::array<Tp, N> args;
TypeID const* arg_types;
};
template <class Tuple>
constexpr bool do_constexpr_test(Tuple&& tup) {
using RawTuple = std::decay_t<Tuple>;
using Tp = ConstexprConstructibleFromTuple<RawTuple>;
return std::make_from_tuple<Tp>(std::forward<Tuple>(tup)).args == tup;
}
// Needed by do_forwarding_test() since it compares pairs of different types.
template <class T1, class T2, class U1, class U2>
inline bool operator==(const std::pair<T1, T2>& lhs, const std::pair<U1, U2>& rhs) {
return lhs.first == rhs.first && lhs.second == rhs.second;
}
template <class ...ExpectTypes, class Tuple>
bool do_forwarding_test(Tuple&& tup) {
using RawTuple = std::decay_t<Tuple>;
using Tp = ConstructibleFromTuple<RawTuple>;
const Tp value = std::make_from_tuple<Tp>(std::forward<Tuple>(tup));
return value.args == tup
&& value.arg_types == &makeArgumentID<ExpectTypes...>();
}
void test_constexpr_construction() {
{
constexpr std::tuple<> tup;
static_assert(do_constexpr_test(tup), "");
}
{
constexpr std::tuple<int> tup(42);
static_assert(do_constexpr_test(tup), "");
}
{
constexpr std::tuple<int, long, void*> tup(42, 101, nullptr);
static_assert(do_constexpr_test(tup), "");
}
{
constexpr std::pair<int, const char*> p(42, "hello world");
static_assert(do_constexpr_test(p), "");
}
{
using Tuple = std::array<int, 3>;
using ValueTp = ConstexprConstructibleFromTuple<Tuple>;
constexpr Tuple arr = {42, 101, -1};
constexpr ValueTp value = std::make_from_tuple<ValueTp>(arr);
static_assert(value.args[0] == arr[0] && value.args[1] == arr[1]
&& value.args[2] == arr[2], "");
}
}
void test_perfect_forwarding() {
{
using Tup = std::tuple<>;
Tup tup;
Tup const& ctup = tup;
assert(do_forwarding_test<>(tup));
assert(do_forwarding_test<>(ctup));
}
{
using Tup = std::tuple<int>;
Tup tup(42);
Tup const& ctup = tup;
assert(do_forwarding_test<int&>(tup));
assert(do_forwarding_test<int const&>(ctup));
assert(do_forwarding_test<int&&>(std::move(tup)));
assert(do_forwarding_test<int const&&>(std::move(ctup)));
}
{
using Tup = std::tuple<int&, const char*, unsigned&&>;
int x = 42;
unsigned y = 101;
Tup tup(x, "hello world", std::move(y));
Tup const& ctup = tup;
assert((do_forwarding_test<int&, const char*&, unsigned&>(tup)));
assert((do_forwarding_test<int&, const char* const&, unsigned &>(ctup)));
assert((do_forwarding_test<int&, const char*&&, unsigned&&>(std::move(tup))));
assert((do_forwarding_test<int&, const char* const&&, unsigned &&>(std::move(ctup))));
}
// test with pair<T, U>
{
using Tup = std::pair<int&, const char*>;
int x = 42;
Tup tup(x, "hello world");
Tup const& ctup = tup;
assert((do_forwarding_test<int&, const char*&>(tup)));
assert((do_forwarding_test<int&, const char* const&>(ctup)));
assert((do_forwarding_test<int&, const char*&&>(std::move(tup))));
assert((do_forwarding_test<int&, const char* const&&>(std::move(ctup))));
}
// test with array<T, I>
{
using Tup = std::array<int, 3>;
Tup tup = {42, 101, -1};
Tup const& ctup = tup;
assert((do_forwarding_test<int&, int&, int&>(tup)));
assert((do_forwarding_test<int const&, int const&, int const&>(ctup)));
assert((do_forwarding_test<int&&, int&&, int&&>(std::move(tup))));
assert((do_forwarding_test<int const&&, int const&&, int const&&>(std::move(ctup))));
}
}
void test_noexcept() {
struct NothrowMoveable {
NothrowMoveable() = default;
NothrowMoveable(NothrowMoveable const&) {}
NothrowMoveable(NothrowMoveable&&) noexcept {}
};
struct TestType {
TestType(int, NothrowMoveable) noexcept {}
TestType(int, int, int) noexcept(false) {}
TestType(long, long, long) noexcept {}
};
{
using Tuple = std::tuple<int, NothrowMoveable>;
Tuple tup; ((void)tup);
Tuple const& ctup = tup; ((void)ctup);
ASSERT_NOT_NOEXCEPT(std::make_from_tuple<TestType>(ctup));
LIBCPP_ASSERT_NOEXCEPT(std::make_from_tuple<TestType>(std::move(tup)));
}
{
using Tuple = std::pair<int, NothrowMoveable>;
Tuple tup; ((void)tup);
Tuple const& ctup = tup; ((void)ctup);
ASSERT_NOT_NOEXCEPT(std::make_from_tuple<TestType>(ctup));
LIBCPP_ASSERT_NOEXCEPT(std::make_from_tuple<TestType>(std::move(tup)));
}
{
using Tuple = std::tuple<int, int, int>;
Tuple tup; ((void)tup);
ASSERT_NOT_NOEXCEPT(std::make_from_tuple<TestType>(tup));
}
{
using Tuple = std::tuple<long, long, long>;
Tuple tup; ((void)tup);
LIBCPP_ASSERT_NOEXCEPT(std::make_from_tuple<TestType>(tup));
}
{
using Tuple = std::array<int, 3>;
Tuple tup; ((void)tup);
ASSERT_NOT_NOEXCEPT(std::make_from_tuple<TestType>(tup));
}
{
using Tuple = std::array<long, 3>;
Tuple tup; ((void)tup);
LIBCPP_ASSERT_NOEXCEPT(std::make_from_tuple<TestType>(tup));
}
}
int main()
{
test_constexpr_construction();
test_perfect_forwarding();
test_noexcept();
}
|
