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
|
// Copyright 2020 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/ranges/ranges.h"
#include <array>
#include <initializer_list>
#include <vector>
#include "testing/gtest/include/gtest/gtest.h"
namespace base {
namespace {
// Test struct with free function overloads for begin and end. Tests whether the
// free functions are found.
struct S {
std::vector<int> v;
};
auto begin(const S& s) {
return s.v.begin();
}
auto end(const S& s) {
return s.v.end();
}
// Test struct with both member and free function overloads for begin and end.
// Tests whether the member function is preferred.
struct T {
constexpr int begin() const { return 1; }
constexpr int end() const { return 1; }
};
constexpr int begin(const T& t) {
return 2;
}
constexpr int end(const T& t) {
return 2;
}
// constexpr utility to generate a std::array. Ensures that a mutable array can
// be used in a constexpr context.
template <size_t N>
constexpr std::array<int, N> GenerateArray() {
std::array<int, N> arr{};
int i = 0;
for (auto* it = ranges::begin(arr); it != ranges::end(arr); ++it) {
*it = i++;
}
return arr;
}
} // namespace
TEST(RangesTest, BeginPrefersMember) {
constexpr T t;
static_assert(ranges::begin(t) == 1, "");
}
TEST(RangesTest, BeginConstexprContainers) {
int arr[1]{};
static_assert(arr == ranges::begin(arr), "");
static constexpr std::initializer_list<int> il = {1, 2, 3};
static_assert(il.begin() == ranges::begin(il), "");
static constexpr std::array<int, 3> array = {1, 2, 3};
static_assert(&array[0] == ranges::begin(array), "");
}
TEST(RangesTest, BeginRegularContainers) {
std::vector<int> vec;
S s;
EXPECT_EQ(vec.begin(), ranges::begin(vec));
EXPECT_EQ(s.v.begin(), ranges::begin(s));
}
TEST(RangesTest, EndPrefersMember) {
constexpr T t;
static_assert(ranges::end(t) == 1, "");
}
TEST(RangesTest, EndConstexprContainers) {
int arr[1]{};
static_assert(arr + 1 == ranges::end(arr), "");
static constexpr std::initializer_list<int> il = {1, 2, 3};
static_assert(il.end() == ranges::end(il), "");
static constexpr std::array<int, 3> array = {1, 2, 3};
static_assert(&array[0] + 3 == ranges::end(array), "");
}
TEST(RangesTest, EndRegularContainers) {
std::vector<int> vec;
S s;
EXPECT_EQ(vec.end(), ranges::end(vec));
EXPECT_EQ(s.v.end(), ranges::end(s));
}
TEST(RangesTest, BeginEndStdArray) {
static constexpr std::array<int, 0> null_array = GenerateArray<0>();
static_assert(ranges::begin(null_array) == ranges::end(null_array), "");
static constexpr std::array<int, 3> array = GenerateArray<3>();
static_assert(array[0] == 0, "");
static_assert(array[1] == 1, "");
static_assert(array[2] == 2, "");
}
} // namespace base
|
