分析代码。 auto set_status = [this](const ParkingStatus::Status status) { last_status_ = status_.type; status_.type = status; };
时间: 2024-04-03 13:33:53 浏览: 72
这段代码是一个lambda表达式,定义了一个名为set_status的函数对象,用于设置停车状态的类型。具体来说,这个lambda表达式接受一个参数status,它表示将要设置的停车状态类型,该类型是ParkingStatus::Status枚举类型的常量。
lambda表达式通过捕获this指针来访问类的成员变量last_status_和status_。它将last_status_设置为当前状态的类型,然后将status_.type设置为传递进来的状态类型。这个lambda表达式的返回值类型是自动推断的,因为没有指定返回值类型。
使用这个lambda表达式的方式可能是将它作为一个函数对象传递给其他函数,以便在需要设置停车状态类型时调用。例如,可以将它传递给一个名为update_status的函数,该函数将在检测到停车状态变化时调用set_status函数对象。这种方式可以使代码更加简洁和易于维护。
相关问题
auto set_status = [this](const ParkingStatus::Status status) { last_status_ = status_.type; status_.type = status; };
这是一个lambda表达式,其中包含一个函数对象,用于设置停车状态的类型。具体来说,这个lambda表达式接受一个参数status,它表示将要设置的停车状态类型。lambda表达式通过捕获this指针来访问类的成员变量last_status_和status_。它将last_status_设置为当前状态的类型,然后将status_.type设置为传递进来的状态类型。这个lambda表达式可以作为一个函数对象传递给其他函数,以便在需要设置停车状态类型时调用。
使用c++代码实现,文档代码功能
要将提供的Python代码转换为C++代码,我们需要考虑以下几个关键点:
1. **类定义**:在C++中,类的定义与Python类似,但语法有所不同。
2. **成员变量和方法**:需要将Python中的属性和方法转换为C++的私有成员变量和公共/私有方法。
3. **数据结构**:Python中的列表和字典需要转换为C++中的`std::vector`和`std::map`等标准库容器。
4. **时间管理**:需要使用C++的时间管理机制来模拟Python中的计时器。
5. **任务调度算法**:需要实现简单的调度算法和优先级非抢占式调度算法。
以下是将Python代码转换为C++代码的一个示例:
### C++ 代码实现
```cpp
#include <iostream>
#include <vector>
#include <map>
#include <algorithm>
#include <cassert>
// Define the Task class
class Task {
public:
int pid;
std::string status;
int arrival;
int priority;
int last_cpusc;
int last_iosc;
std::vector<std::pair<int, int>> pieces;
void notify_runned(int delta) {
// Update the task's running time
}
void notify_pick_to_run() {
// Notify that the task is picked to run
}
void notify_in_wait() {
// Notify that the task is in wait state
}
};
// Define the Scheduler class
class Scheduler {
private:
std::vector<int> created;
int timer;
std::string scheduler_type;
int last_cpu;
int last_io;
int last_schedule;
std::vector<int> cpu_queue;
std::vector<int> io_queue;
std::map<int, Task> tasks;
public:
Scheduler(int timer, const std::string& scheduler_type)
: timer(timer), scheduler_type(scheduler_type), last_cpu(-1), last_io(-1), last_schedule(0) {}
void create(const Task& task) {
if (task.status != "exited") {
created.push_back(task.pid);
}
}
int get_next_arrival() {
if (tasks.empty()) {
return -1;
}
std::vector<int> pids;
for (const auto& pair : tasks) {
pids.push_back(pair.first);
}
std::sort(pids.begin(), pids.end());
std::vector<int> ticks;
for (int pid : pids) {
ticks.push_back(tasks[pid].arrival);
}
std::sort(ticks.begin(), ticks.end());
for (int tick : ticks) {
if (tick > current_tick) {
return tick;
}
}
return -1;
}
void schedule() {
int last_tick = last_schedule;
last_schedule = current_tick;
int delta = current_tick - last_tick;
if (last_cpu >= 0) {
tasks[last_cpu].notify_runned(delta);
}
if (last_io >= 0) {
tasks[last_io].notify_runned(delta);
}
if (last_cpu >= 0 && std::find(cpu_queue.begin(), cpu_queue.end(), last_cpu) != cpu_queue.end() && tasks[last_cpu].status != "cpu") {
cpu_queue.erase(std::remove(cpu_queue.begin(), cpu_queue.end(), last_cpu), cpu_queue.end());
}
if (last_io >= 0 && std::find(io_queue.begin(), io_queue.end(), last_io) != io_queue.end() && tasks[last_io].status != "io") {
io_queue.erase(std::remove(io_queue.begin(), io_queue.end(), last_io), io_queue.end());
}
for (int i : created) {
if (tasks[i].status == "exited") {
created.erase(std::remove(created.begin(), created.end(), i), created.end());
if (std::find(cpu_queue.begin(), cpu_queue.end(), i) != cpu_queue.end()) {
cpu_queue.erase(std::remove(cpu_queue.begin(), cpu_queue.end(), i), cpu_queue.end());
}
if (std::find(io_queue.begin(), io_queue.end(), i) != io_queue.end()) {
io_queue.erase(std::remove(io_queue.begin(), io_queue.end(), i), io_queue.end());
}
if (i == last_cpu) {
last_cpu = -1;
}
if (i == last_io) {
last_io = -1;
}
}
}
if (created.empty()) {
int next_arrival = get_next_arrival();
if (next_arrival >= 0) {
timer.add(next_arrival, &Scheduler::schedule);
}
return;
}
assert(scheduler_type == "simple" || scheduler_type == "priority");
if (scheduler_type == "simple") {
simple_schedule();
} else {
priority_schedule_non_preemptive();
}
int cpu_timeout = INT32_MAX, io_timeout = INT32_MAX;
if (!cpu_queue.empty()) {
if (last_cpu == -1 || tasks[last_cpu].status != "cpu") {
last_cpu = cpu_queue.front();
tasks[last_cpu].notify_pick_to_run();
cpu_timeout = std::min(tasks[last_cpu].pieces[0].second - (current_tick - tasks[last_cpu].last_cpusc), tasks[last_cpu].pieces[0].second);
} else {
last_cpu = -1;
}
}
if (!io_queue.empty()) {
if (last_io == -1 || tasks[last_io].status != "io") {
last_io = io_queue.front();
tasks[last_io].notify_pick_to_run();
io_timeout = std::min(tasks[last_io].pieces[0].second - (current_tick - tasks[last_io].last_iosc), tasks[last_io].pieces[0].second);
} else {
last_io = -1;
}
}
assert(cpu_timeout != INT32_MAX || io_timeout != INT32_MAX);
int callback_timepoint = current_tick + std::min(cpu_timeout, io_timeout);
timer.add(callback_timepoint, &Scheduler::schedule);
}
void simple_schedule() {
for (int i : created) {
if ((tasks[i].status == "cpu" || tasks[i].status == "cpu_wait") && std::find(cpu_queue.begin(), cpu_queue.end(), i) == cpu_queue.end()) {
tasks[i].notify_in_wait();
cpu_queue.push_back(i);
assert(tasks[i].status != "cpu");
} else if ((tasks[i].status == "io" || tasks[i].status == "io_wait") && std::find(io_queue.begin(), io_queue.end(), i) == io_queue.end()) {
tasks[i].notify_in_wait();
io_queue.push_back(i);
assert(tasks[i].status != "io");
}
}
if (last_cpu >= 0 && std::find(cpu_queue.begin(), cpu_queue.end(), last_cpu) != cpu_queue.end() && tasks[last_cpu].status == "cpu_wait") {
cpu_queue.erase(std::remove(cpu_queue.begin(), cpu_queue.end(), last_cpu), cpu_queue.end());
cpu_queue.push_back(last_cpu);
}
if (last_io >= 0 && std::find(io_queue.begin(), io_queue.end(), last_io) != io_queue.end() && tasks[last_io].status == "io_wait") {
io_queue.erase(std::remove(io_queue.begin(), io_queue.end(), last_io), io_queue.end());
io_queue.push_back(last_io);
}
assert(!cpu_queue.empty() || !io_queue.empty());
}
void priority_schedule_non_preemptive() {
auto sort_pids_by_priority = [](const std::vector<int>& pids, const std::map<int, Task>& tasks) {
std::vector<std::pair<int, int>> ret;
for (int i : pids) {
ret.emplace_back(i, tasks.at(i).priority);
}
std::sort(ret.begin(), ret.end(), [](const std::pair<int, int>& a, const std::pair<int, int>& b) {
return a.second < b.second;
});
std::vector<int> ret2;
for (const auto& pair : ret) {
ret2.push_back(pair.first);
}
return ret2;
};
auto find_last_index = [](const std::vector<int>& pids, int prio, const std::map<int, Task>& tasks) {
for (size_t index = 0; index < pids.size(); ++index) {
if (tasks.at(pids[index]).priority > prio) {
return static_cast<int>(index);
}
}
return static_cast<int>(pids.size());
};
for (int i : created) {
if ((tasks[i].status == "cpu" || tasks[i].status == "cpu_wait") && std::find(cpu_queue.begin(), cpu_queue.end(), i) == cpu_queue.end()) {
tasks[i].notify_in_wait();
cpu_queue.push_back(i);
assert(tasks[i].status != "cpu");
} else if ((tasks[i].status == "io" || tasks[i].status == "io_wait") && std::find(io_queue.begin(), io_queue.end(), i) == io_queue.end()) {
tasks[i].notify_in_wait();
io_queue.push_back(i);
assert(tasks[i].status != "io");
}
}
cpu_queue = sort_pids_by_priority(cpu_queue, tasks);
io_queue = sort_pids_by_priority(io_queue, tasks);
if (last_cpu >= 0 && std::find(cpu_queue.begin(), cpu_queue.end(), last_cpu) != cpu_queue.end() && tasks[last_cpu].status == "cpu_wait") {
cpu_queue.erase(std::remove(cpu_queue.begin(), cpu_queue.end(), last_cpu), cpu_queue.end());
cpu_queue.insert(cpu_queue.begin() + find_last_index(cpu_queue, tasks[last_cpu].priority, tasks), last_cpu);
}
if (last_io >= 0 && std::find(io_queue.begin(), io_queue.end(), last_io) != io_queue.end() && tasks[last_io].status == "io_wait") {
io_queue.erase(std::remove(io_queue.begin(), io_queue.end(), last_io), io_queue.end());
io_queue.insert(io_queue.begin() + find_last_index(io_queue, tasks[last_io].priority, tasks), last_io);
}
assert(!cpu_queue.empty() || !io_queue.empty());
}
};
// Define the Timer class
class Timer {
private:
Scheduler* scheduler;
std::map<int, std::vector<void(Scheduler::*)()>> event_list;
public:
void set_scheduler(Scheduler* s) {
scheduler = s;
}
void add(int tick_expire, void (Scheduler::*handler)()) {
if (event_list.find(tick_expire) == event_list.end()) {
event_list[tick_expire] = {};
}
event_list[tick_expire].push_back(handler);
// Move scheduler to end
auto it = event_list.find(tick_expire);
if (it != event_list.end() && it->second.size() > 1) {
std::swap(it->second.back(), it->second[it->second.size() - 1]);
}
}
void mainloop() {
while (!event_list.empty()) {
int next_tick = event_list.begin()->first;
current_tick = next_tick;
while (!event_list[next_tick].empty()) {
(scheduler->*(event_list[next_tick].front()))();
event_list[next_tick].erase(event_list[next_tick].begin());
}
if (event_list[next_tick].empty()) {
event_list.erase(next_tick);
}
}
}
};
// Global variable for current tick
int current_tick = 0;
int main() {
// Example usage
Timer timer;
Scheduler scheduler(&timer, "simple");
// Create some tasks
Task t1{1, "cpu", 0, 1, 0, 0, {{10, 10}}};
Task t2{2, "io", 5, 2, 0, 0, {{15, 15}}};
scheduler.create(t1);
scheduler.create(t2);
// Set the scheduler in the timer
timer.set_scheduler(&scheduler);
// Start the main loop
timer.mainloop();
return 0;
}
```
### 解释
1. **Task 类**:定义了任务的基本属性和方法。
2. **Scheduler 类**:实现了任务的创建、调度、状态更新等功能。
3. **Timer 类**:管理事件的定时触发。
4. **main 函数**:示例用法,创建任务并启动调度器。
这个实现假设了一些辅助函数(如 `notify_runned` 和 `notify_pick_to_run`)的具体实现细节,这些可以根据实际需求进一步完善。
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