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
|
#include <xenium/left_right.hpp>
#include <gtest/gtest.h>
#include <vector>
#include <thread>
#include <random>
namespace {
TEST(LeftRight, read_provides_initial_value)
{
xenium::left_right<int> lr{42};
lr.read([](int v) {
ASSERT_EQ(42, v);
});
}
TEST(LeftRight, read_can_return_value)
{
xenium::left_right<int> lr{42};
auto v = lr.read([](int v) { return v; });
ASSERT_EQ(42, v);
}
TEST(LeftRight, read_provides_updated_value)
{
xenium::left_right<int> lr{0};
lr.update([](int& v) { v = 42; });
lr.read([](int v) {
ASSERT_EQ(42, v);
});
lr.update([](int& v) { ++v; });
lr.read([](int v) {
ASSERT_EQ(43, v);
});
}
TEST(LeftRight, parallel_usage)
{
constexpr int MaxIterations = 8000;
xenium::left_right<int> lr{0};
std::vector<std::thread> threads;
for (int i = 0; i < 4; ++i)
{
threads.push_back(std::thread([i, &lr, MaxIterations]
{
// oh my... MSVC complains if this variable is NOT captured; clang complains if it IS captured.
(void)MaxIterations;
std::mt19937 rand;
rand.seed(i);
for (int j = 0; j < MaxIterations; ++j)
{
int last_value = 0;
if (rand() % 32 == 0) {
lr.update([](int& v) { ++v; });
} else {
lr.read([&last_value](const int& v) {
EXPECT_GE(v, last_value);
last_value = v;
});
}
}
}));
}
for (auto& thread : threads)
thread.join();
}
}
|
