/*
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* =====================================================================================
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*
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* Filename: robust.h
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*
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* Description:
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*
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* Version: 1.0
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* Created: 2021年04月27日 10时04分29秒
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* Revision: none
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* Compiler: gcc
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*
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* Author: Li Chao (), lichao@aiotlink.com
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* Organization:
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*
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* =====================================================================================
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*/
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#ifndef ROBUST_Q31RCWYU
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#define ROBUST_Q31RCWYU
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#include "log.h"
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#include <atomic>
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#include <chrono>
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#include <memory>
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#include <mutex>
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#include <string>
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#include <sys/file.h>
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#include <sys/ipc.h>
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#include <sys/sem.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <unistd.h>
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namespace robust
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{
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using namespace std::chrono;
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using namespace std::chrono_literals;
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constexpr uint64_t MaskBits(int nbits) { return (uint64_t(1) << nbits) - 1; }
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void QuickSleep();
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class CasMutex
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{
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typedef uint64_t locker_t;
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static inline locker_t this_locker() { return pthread_self(); }
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static const uint64_t kLockerMask = MaskBits(63);
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public:
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CasMutex() :
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meta_(0) {}
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int try_lock()
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{
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auto old = meta_.load();
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int r = 0;
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if (!Locked(old)) {
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r = MetaCas(old, Meta(1, this_locker()));
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}
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return r;
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}
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int lock()
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{
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int r = 0;
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do {
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r = try_lock();
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} while (r == 0);
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return r;
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}
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void unlock()
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{
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auto old = meta_.load();
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if (Locked(old) && Locker(old) == this_locker()) {
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MetaCas(old, Meta(0, this_locker()));
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}
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}
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private:
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std::atomic<uint64_t> meta_;
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bool Locked(uint64_t meta) { return (meta >> 63) == 1; }
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locker_t Locker(uint64_t meta) { return meta & kLockerMask; }
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uint64_t Meta(uint64_t lk, locker_t lid) { return (lk << 63) | lid; }
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bool MetaCas(uint64_t exp, uint64_t val) { return meta_.compare_exchange_strong(exp, val); }
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};
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class NullMutex
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{
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public:
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bool try_lock() { return true; }
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void lock() {}
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void unlock() {}
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};
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// flock + mutex
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class FMutex
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{
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public:
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typedef uint64_t id_t;
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FMutex(id_t id) :
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id_(id), fd_(Open(id_))
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{
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if (fd_ == -1) { throw "error create mutex!"; }
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}
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~FMutex() { Close(fd_); }
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bool try_lock();
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void lock();
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void unlock();
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private:
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static std::string GetPath(id_t id)
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{
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const std::string dir("/tmp/.bhome_mtx");
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mkdir(dir.c_str(), 0777);
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return dir + "/fm_" + std::to_string(id);
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}
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static int Open(id_t id) { return open(GetPath(id).c_str(), O_CREAT | O_RDWR, 0666); }
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static int Close(int fd) { return close(fd); }
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id_t id_;
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int fd_;
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std::mutex mtx_;
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};
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union semun {
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int val; /* Value for SETVAL */
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struct semid_ds *buf; /* Buffer for IPC_STAT, IPC_SET */
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unsigned short *array; /* Array for GETALL, SETALL */
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struct seminfo *__buf; /* Buffer for IPC_INFO
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(Linux-specific) */
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};
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class SemMutex
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{
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public:
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SemMutex(key_t key) :
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key_(key), sem_id_(semget(key, 1, 0666 | IPC_CREAT))
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{
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if (sem_id_ == -1) { throw "error create semaphore."; }
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union semun init_val;
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init_val.val = 1;
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semctl(sem_id_, 0, SETVAL, init_val);
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}
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~SemMutex()
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{
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// semctl(sem_id_, 0, IPC_RMID, semun{});
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}
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bool try_lock()
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{
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sembuf op = {0, -1, SEM_UNDO | IPC_NOWAIT};
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return semop(sem_id_, &op, 1) == 0;
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}
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void lock()
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{
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sembuf op = {0, -1, SEM_UNDO};
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semop(sem_id_, &op, 1);
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}
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void unlock()
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{
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sembuf op = {0, 1, SEM_UNDO};
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semop(sem_id_, &op, 1);
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}
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private:
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key_t key_;
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int sem_id_;
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};
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template <class Lock>
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class Guard
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{
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public:
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Guard(Lock &l) :
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l_(l) { l_.lock(); }
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~Guard() { l_.unlock(); }
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private:
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Guard(const Guard &);
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Guard(Guard &&);
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Lock &l_;
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};
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template <class D, class Alloc = std::allocator<D>>
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class CircularBuffer
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{
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typedef uint32_t size_type;
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typedef uint32_t count_type;
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typedef uint64_t meta_type;
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static size_type Pos(meta_type meta) { return meta & 0xFFFFFFFF; }
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static count_type Count(meta_type meta) { return meta >> 32; }
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static meta_type Meta(meta_type count, size_type pos) { return (count << 32) | pos; }
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public:
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typedef D Data;
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CircularBuffer(const size_type cap) :
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CircularBuffer(cap, Alloc()) {}
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CircularBuffer(const size_type cap, Alloc const &al) :
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capacity_(cap + 1), mhead_(0), mtail_(0), al_(al), buf(al_.allocate(capacity_))
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{
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if (!buf) {
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throw("robust CircularBuffer allocate error: alloc buffer failed, out of mem!");
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} else {
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memset(&buf[0], 0, sizeof(D) * capacity_);
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}
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}
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~CircularBuffer() { al_.deallocate(buf, capacity_); }
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bool push_back(const Data d)
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{
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auto old = mtail();
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auto pos = Pos(old);
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auto full = ((capacity_ + pos + 1 - head()) % capacity_ == 0);
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if (!full) {
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buf[pos] = d;
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return mtail_.compare_exchange_strong(old, next(old));
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}
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return false;
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}
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bool pop_front(Data &d)
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{
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auto old = mhead();
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auto pos = Pos(old);
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if (!(pos == tail())) {
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d = buf[pos];
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return mhead_.compare_exchange_strong(old, next(old));
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} else {
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return false;
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}
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}
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private:
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CircularBuffer(const CircularBuffer &);
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CircularBuffer(CircularBuffer &&);
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CircularBuffer &operator=(const CircularBuffer &) = delete;
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CircularBuffer &operator=(CircularBuffer &&) = delete;
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meta_type next(meta_type meta) const { return Meta(Count(meta) + 1, (Pos(meta) + 1) % capacity_); }
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size_type head() const { return Pos(mhead()); }
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size_type tail() const { return Pos(mtail()); }
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meta_type mhead() const { return mhead_.load(); }
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meta_type mtail() const { return mtail_.load(); }
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// data
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const size_type capacity_;
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std::atomic<meta_type> mhead_;
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std::atomic<meta_type> mtail_;
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Alloc al_;
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typename Alloc::pointer buf = nullptr;
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};
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template <unsigned PowerSize = 4, class Int = int64_t>
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class AtomicQueue
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{
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public:
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typedef uint32_t size_type;
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typedef Int Data;
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typedef std::atomic<Data> AData;
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static_assert(sizeof(Data) == sizeof(AData));
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enum {
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power = PowerSize,
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capacity = (1 << power),
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mask = capacity - 1,
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};
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AtomicQueue() { memset(this, 0, sizeof(*this)); }
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size_type head() const { return head_.load(); }
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size_type tail() const { return tail_.load(); }
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bool like_empty() const { return head() == tail() && Empty(buf[head()]); }
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bool like_full() const { return head() == tail() && !Empty(buf[head()]); }
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bool push(const Data d, bool try_more = false)
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{
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bool r = false;
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size_type i = 0;
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do {
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auto pos = tail();
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if (tail_.compare_exchange_strong(pos, Next(pos))) {
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auto cur = buf[pos].load();
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r = Empty(cur) && buf[pos].compare_exchange_strong(cur, Enc(d));
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}
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} while (try_more && !r && ++i < capacity);
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return r;
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}
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bool pop(Data &d, bool try_more = false)
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{
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bool r = false;
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Data cur;
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size_type i = 0;
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do {
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auto pos = head();
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if (head_.compare_exchange_strong(pos, Next(pos))) {
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cur = buf[pos].load();
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r = !Empty(cur) && buf[pos].compare_exchange_strong(cur, 0);
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}
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} while (try_more && !r && ++i < capacity);
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if (r) { d = Dec(cur); }
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return r;
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}
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private:
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static_assert(std::is_integral<Data>::value, "Data must be integral type!");
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static_assert(std::is_signed<Data>::value, "Data must be signed type!");
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static_assert(PowerSize < 10, "RobustQ63 max size is 2^10!");
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static inline bool Empty(const Data d) { return (d & 1) == 0; } // lowest bit 1 means data ok.
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static inline Data Enc(const Data d) { return (d << 1) | 1; } // lowest bit 1 means data ok.
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static inline Data Dec(const Data d) { return d >> 1; } // lowest bit 1 means data ok.
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static size_type Next(const size_type index) { return (index + 1) & mask; }
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std::atomic<size_type> head_;
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std::atomic<size_type> tail_;
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AData buf[capacity];
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};
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} // namespace robust
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#endif // end of include guard: ROBUST_Q31RCWYU
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