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
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
|
//===----------------------------------------------------------------------===//
//
// 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++03
// <iterator>
// template <class C> constexpr auto begin(C& c) -> decltype(c.begin());
// template <class C> constexpr auto begin(const C& c) -> decltype(c.begin());
// template <class C> constexpr auto cbegin(const C& c) -> decltype(std::begin(c)); // C++14
// template <class C> constexpr auto cend(const C& c) -> decltype(std::end(c)); // C++14
// template <class C> constexpr auto end (C& c) -> decltype(c.end());
// template <class C> constexpr auto end (const C& c) -> decltype(c.end());
// template <class E> constexpr reverse_iterator<const E*> rbegin(initializer_list<E> il);
// template <class E> constexpr reverse_iterator<const E*> rend (initializer_list<E> il);
//
// template <class C> auto constexpr rbegin(C& c) -> decltype(c.rbegin()); // C++14
// template <class C> auto constexpr rbegin(const C& c) -> decltype(c.rbegin()); // C++14
// template <class C> auto constexpr rend(C& c) -> decltype(c.rend()); // C++14
// template <class C> constexpr auto rend(const C& c) -> decltype(c.rend()); // C++14
// template <class T, size_t N> reverse_iterator<T*> constexpr rbegin(T (&array)[N]); // C++14
// template <class T, size_t N> reverse_iterator<T*> constexpr rend(T (&array)[N]); // C++14
// template <class C> constexpr auto crbegin(const C& c) -> decltype(std::rbegin(c)); // C++14
// template <class C> constexpr auto crend(const C& c) -> decltype(std::rend(c)); // C++14
//
// All of these are constexpr in C++17
#include <array>
#include <cassert>
#include <initializer_list>
#include <iterator>
#include <list>
#include <vector>
#include "test_macros.h"
// Throughout this test, we consistently compare against c.begin() instead of c.cbegin()
// because some STL types (e.g. initializer_list) don't syntactically support il.cbegin().
// Note that std::cbegin(x) effectively calls std::as_const(x).begin(), not x.cbegin();
// see the ContainerHijacker test case below.
TEST_CONSTEXPR_CXX14 bool test_arrays_and_initializer_lists_forward()
{
{
int a[] = {1, 2, 3};
ASSERT_SAME_TYPE(decltype(std::begin(a)), int*);
ASSERT_SAME_TYPE(decltype(std::end(a)), int*);
assert(std::begin(a) == a);
assert(std::end(a) == a + 3);
#if TEST_STD_VER > 11
ASSERT_SAME_TYPE(decltype(std::cbegin(a)), const int*);
ASSERT_SAME_TYPE(decltype(std::cend(a)), const int*);
assert(std::cbegin(a) == a);
assert(std::cend(a) == a + 3);
#endif
const auto& ca = a;
ASSERT_SAME_TYPE(decltype(std::begin(ca)), const int*);
ASSERT_SAME_TYPE(decltype(std::end(ca)), const int*);
assert(std::begin(ca) == a);
assert(std::end(ca) == a + 3);
#if TEST_STD_VER > 11
ASSERT_SAME_TYPE(decltype(std::cbegin(ca)), const int*);
ASSERT_SAME_TYPE(decltype(std::cend(ca)), const int*);
assert(std::cbegin(ca) == a);
assert(std::cend(ca) == a + 3);
#endif
}
{
std::initializer_list<int> il = {1, 2, 3};
ASSERT_SAME_TYPE(decltype(std::begin(il)), const int*);
ASSERT_SAME_TYPE(decltype(std::end(il)), const int*);
assert(std::begin(il) == il.begin());
assert(std::end(il) == il.end());
#if TEST_STD_VER > 11
ASSERT_SAME_TYPE(decltype(std::cbegin(il)), const int*);
ASSERT_SAME_TYPE(decltype(std::cend(il)), const int*);
assert(std::cbegin(il) == il.begin());
assert(std::cend(il) == il.end());
#endif
const auto& cil = il;
ASSERT_SAME_TYPE(decltype(std::begin(cil)), const int*);
ASSERT_SAME_TYPE(decltype(std::end(cil)), const int*);
assert(std::begin(cil) == il.begin());
assert(std::end(cil) == il.end());
#if TEST_STD_VER > 11
ASSERT_SAME_TYPE(decltype(std::cbegin(cil)), const int*);
ASSERT_SAME_TYPE(decltype(std::cend(cil)), const int*);
assert(std::cbegin(cil) == il.begin());
assert(std::cend(cil) == il.end());
#endif
}
return true;
}
#if TEST_STD_VER > 11
TEST_CONSTEXPR_CXX17 bool test_arrays_and_initializer_lists_backward()
{
{
int a[] = {1, 2, 3};
ASSERT_SAME_TYPE(decltype(std::rbegin(a)), std::reverse_iterator<int*>);
ASSERT_SAME_TYPE(decltype(std::rend(a)), std::reverse_iterator<int*>);
assert(std::rbegin(a).base() == a + 3);
assert(std::rend(a).base() == a);
ASSERT_SAME_TYPE(decltype(std::crbegin(a)), std::reverse_iterator<const int*>);
ASSERT_SAME_TYPE(decltype(std::crend(a)), std::reverse_iterator<const int*>);
assert(std::crbegin(a).base() == a + 3);
assert(std::crend(a).base() == a);
const auto& ca = a;
ASSERT_SAME_TYPE(decltype(std::rbegin(ca)), std::reverse_iterator<const int*>);
ASSERT_SAME_TYPE(decltype(std::rend(ca)), std::reverse_iterator<const int*>);
assert(std::rbegin(ca).base() == a + 3);
assert(std::rend(ca).base() == a);
ASSERT_SAME_TYPE(decltype(std::crbegin(ca)), std::reverse_iterator<const int*>);
ASSERT_SAME_TYPE(decltype(std::crend(ca)), std::reverse_iterator<const int*>);
assert(std::crbegin(ca).base() == a + 3);
assert(std::crend(ca).base() == a);
}
{
std::initializer_list<int> il = {1, 2, 3};
ASSERT_SAME_TYPE(decltype(std::rbegin(il)), std::reverse_iterator<const int*>);
ASSERT_SAME_TYPE(decltype(std::rend(il)), std::reverse_iterator<const int*>);
assert(std::rbegin(il).base() == il.end());
assert(std::rend(il).base() == il.begin());
ASSERT_SAME_TYPE(decltype(std::crbegin(il)), std::reverse_iterator<const int*>);
ASSERT_SAME_TYPE(decltype(std::crend(il)), std::reverse_iterator<const int*>);
assert(std::crbegin(il).base() == il.end());
assert(std::crend(il).base() == il.begin());
const auto& cil = il;
ASSERT_SAME_TYPE(decltype(std::rbegin(cil)), std::reverse_iterator<const int*>);
ASSERT_SAME_TYPE(decltype(std::rend(cil)), std::reverse_iterator<const int*>);
assert(std::rbegin(cil).base() == il.end());
assert(std::rend(cil).base() == il.begin());
ASSERT_SAME_TYPE(decltype(std::crbegin(cil)), std::reverse_iterator<const int*>);
ASSERT_SAME_TYPE(decltype(std::crend(cil)), std::reverse_iterator<const int*>);
assert(std::crbegin(cil).base() == il.end());
assert(std::crend(cil).base() == il.begin());
}
return true;
}
#endif
template<typename C>
TEST_CONSTEXPR_CXX14 bool test_container() {
C c = {1, 2, 3};
ASSERT_SAME_TYPE(decltype(std::begin(c)), typename C::iterator);
ASSERT_SAME_TYPE(decltype(std::end(c)), typename C::iterator);
assert(std::begin(c) == c.begin());
assert(std::end(c) == c.end());
#if TEST_STD_VER > 11
ASSERT_SAME_TYPE(decltype(std::cbegin(c)), typename C::const_iterator);
ASSERT_SAME_TYPE(decltype(std::cend(c)), typename C::const_iterator);
assert(std::cbegin(c) == c.begin());
assert(std::cend(c) == c.end());
ASSERT_SAME_TYPE(decltype(std::rbegin(c)), typename C::reverse_iterator);
ASSERT_SAME_TYPE(decltype(std::rend(c)), typename C::reverse_iterator);
assert(std::rbegin(c).base() == c.end());
assert(std::rend(c).base() == c.begin());
ASSERT_SAME_TYPE(decltype(std::crbegin(c)), typename C::const_reverse_iterator);
ASSERT_SAME_TYPE(decltype(std::crend(c)), typename C::const_reverse_iterator);
assert(std::crbegin(c).base() == c.end());
assert(std::crend(c).base() == c.begin());
#endif
const C& cc = c;
ASSERT_SAME_TYPE(decltype(std::begin(cc)), typename C::const_iterator);
ASSERT_SAME_TYPE(decltype(std::end(cc)), typename C::const_iterator);
assert(std::begin(cc) == c.begin());
assert(std::end(cc) == c.end());
#if TEST_STD_VER > 11
ASSERT_SAME_TYPE(decltype(std::cbegin(cc)), typename C::const_iterator);
ASSERT_SAME_TYPE(decltype(std::cend(cc)), typename C::const_iterator);
assert(std::cbegin(cc) == c.begin());
assert(std::cend(cc) == c.end());
ASSERT_SAME_TYPE(decltype(std::rbegin(cc)), typename C::const_reverse_iterator);
ASSERT_SAME_TYPE(decltype(std::rend(cc)), typename C::const_reverse_iterator);
assert(std::rbegin(cc).base() == c.end());
assert(std::rend(cc).base() == c.begin());
ASSERT_SAME_TYPE(decltype(std::crbegin(cc)), typename C::const_reverse_iterator);
ASSERT_SAME_TYPE(decltype(std::crend(cc)), typename C::const_reverse_iterator);
assert(std::crbegin(cc).base() == c.end());
assert(std::crend(cc).base() == c.begin());
#endif
return true;
}
struct ArrayHijacker {
friend constexpr int begin(ArrayHijacker(&)[3]) { return 42; }
friend constexpr int end(ArrayHijacker(&)[3]) { return 42; }
friend constexpr int begin(const ArrayHijacker(&)[3]) { return 42; }
friend constexpr int end(const ArrayHijacker(&)[3]) { return 42; }
};
struct ContainerHijacker {
int *a_;
constexpr int *begin() const { return a_; }
constexpr int *end() const { return a_ + 3; }
constexpr int *rbegin() const { return a_; }
constexpr int *rend() const { return a_ + 3; }
friend constexpr int begin(ContainerHijacker&) { return 42; }
friend constexpr int end(ContainerHijacker&) { return 42; }
friend constexpr int begin(const ContainerHijacker&) { return 42; }
friend constexpr int end(const ContainerHijacker&) { return 42; }
friend constexpr int cbegin(ContainerHijacker&) { return 42; }
friend constexpr int cend(ContainerHijacker&) { return 42; }
friend constexpr int cbegin(const ContainerHijacker&) { return 42; }
friend constexpr int cend(const ContainerHijacker&) { return 42; }
friend constexpr int rbegin(ContainerHijacker&) { return 42; }
friend constexpr int rend(ContainerHijacker&) { return 42; }
friend constexpr int rbegin(const ContainerHijacker&) { return 42; }
friend constexpr int rend(const ContainerHijacker&) { return 42; }
friend constexpr int crbegin(ContainerHijacker&) { return 42; }
friend constexpr int crend(ContainerHijacker&) { return 42; }
friend constexpr int crbegin(const ContainerHijacker&) { return 42; }
friend constexpr int crend(const ContainerHijacker&) { return 42; }
};
TEST_CONSTEXPR_CXX17 bool test_adl_proofing() {
// https://llvm.org/PR28927
{
ArrayHijacker a[3] = {};
assert(begin(a) == 42);
assert(end(a) == 42);
assert(std::begin(a) == a);
assert(std::end(a) == a + 3);
#if TEST_STD_VER > 11
assert(std::cbegin(a) == a);
assert(std::cend(a) == a + 3);
assert(std::rbegin(a).base() == a + 3);
assert(std::rend(a).base() == a);
assert(std::crbegin(a).base() == a + 3);
assert(std::crend(a).base() == a);
#endif
}
{
int a[3] = {};
ContainerHijacker c{a};
assert(begin(c) == 42);
assert(end(c) == 42);
assert(std::begin(c) == a);
assert(std::end(c) == a + 3);
#if TEST_STD_VER > 11
assert(std::cbegin(c) == a);
assert(std::cend(c) == a + 3);
assert(std::rbegin(c) == a);
assert(std::rend(c) == a + 3);
assert(std::crbegin(c) == a);
assert(std::crend(c) == a + 3);
#endif
}
return true;
}
int main(int, char**) {
test_arrays_and_initializer_lists_forward();
#if TEST_STD_VER > 11
test_arrays_and_initializer_lists_backward();
#endif
test_container<std::array<int, 3>>();
test_container<std::list<int>>();
test_container<std::vector<int>>();
test_adl_proofing();
#if TEST_STD_VER > 11
static_assert(test_arrays_and_initializer_lists_forward(), "");
#endif
#if TEST_STD_VER > 14
static_assert(test_arrays_and_initializer_lists_backward());
static_assert(test_container<std::array<int, 3>>());
static_assert(test_adl_proofing());
#endif
return 0;
}
|
