mpmc_ring_queue.h

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#ifndef CPPCOMMON_THREADS_MPMC_RING_QUEUE_H
#define CPPCOMMON_THREADS_MPMC_RING_QUEUE_H
 
#include <atomic>
#include <cassert>
#include <cstdio>
#include <cstring>
#include <utility>
 
namespace CppCommon {
 
 
template<typename T>
class MPMCRingQueue
{
public:
 
    explicit MPMCRingQueue(size_t capacity);
    MPMCRingQueue(const MPMCRingQueue&) = delete;
    MPMCRingQueue(MPMCRingQueue&&) = delete;
    ~MPMCRingQueue() { delete[] _buffer; }
 
    MPMCRingQueue& operator=(const MPMCRingQueue&) = delete;
    MPMCRingQueue& operator=(MPMCRingQueue&&) = delete;
 
    explicit operator bool() const noexcept { return !empty(); }
 
    bool empty() const noexcept { return (size() == 0); }
    size_t capacity() const noexcept { return _capacity; }
    size_t size() const noexcept;
 
 
    bool Enqueue(const T& item);
 
    bool Enqueue(T&& item);
 
 
    bool Dequeue(T& item);
 
private:
    struct Node
    {
        std::atomic<size_t> sequence;
        T value;
    };
 
    typedef char cache_line_pad[128];
 
    cache_line_pad _pad0;
    const size_t _capacity;
    const size_t _mask;
    Node* const _buffer;
 
    cache_line_pad _pad1;
    std::atomic<size_t> _head;
    cache_line_pad _pad2;
    std::atomic<size_t> _tail;
    cache_line_pad _pad3;
};
 
} // namespace CppCommon
 
#include "mpmc_ring_queue.inl"
 
#endif // CPPCOMMON_THREADS_MPMC_RING_QUEUE_H