#include
template
LockFreeQueue() {Node* dummy = new Node();head_ = tail_ = dummy;}~LockFreeQueue() {while (Node* const old_head = head_) {head_ = old_head->next_;delete old_head;}}void push(const T& value) {Node* new_node = new Node(value);tail_->next_ = new_node;tail_ = new_node;size_.fetch_add(1, std::memory_order_release);}bool try_pop(T& value) {Node* old_head = head_;for (;;) {Node* const new_head = old_head->next_;if (new_head == nullptr) {return false;}if (head_.compare_exchange_weak(old_head, new_head, std::memory_order_acquire)) {value = new_head->value_;size_.fetch_sub(1, std::memory_order_release);delete old_head;return true;}}}bool empty() const {return size_.load(std::memory_order_acquire) == 0;}
private:
struct Node {T value_;Node* next_;explicit Node(const T& value) : value_(value), next_(nullptr) {}Node() : next_(nullptr) {}};Node* head_;std::atomic<Node*> tail_;std::atomic<size_t> size_{0};
};
