【Linux】C++模拟实现多线程编程之生产者与消费者模型

桃扇骨 2023-01-04 11:57 180阅读 0赞

### 生产者与消费者模型 ###

*  C++模拟多线程生产者与消费者模型
 *   *  方法一：互斥量与条件变量模拟实现
     *  方法二：信号量模拟实现

# C++模拟多线程生产者与消费者模型 #

## 方法一：互斥量与条件变量模拟实现 ##

#include <stdio.h> 
    #include <unistd.h>
    #include <pthread.h>
    #include <iostream>
    #include <queue>
    using namespace std;
    // 生产着与消费者模型
    // 1.线程安全的队列( queue )
    // 互斥：pthread_mutex_t
    // 同步：pthread_cond_t
    // 2.两种线程：生产者线程 + 消费者线程
    // 生产者线程->入口函数
    // 消费者线程->入口函数
    
    
    
    #define THREAD_COUNT 4
    
    template<class T>
    class BlockQueue
    { 
        public:
        BlockQueue()
        { 
            capacity = 1;  //初始化默认队列大小
            lock = PTHREAD_MUTEX_INITIALIZER; //初始化互斥锁
            //初始化 条件变量
            producer_cond = PTHREAD_COND_INITIALIZER;
            consumer_cond = PTHREAD_COND_INITIALIZER;
        }
        ~BlockQueue()
        { 
            pthread_mutex_destroy(&lock);
            pthread_cond_destroy(&consumer_cond);
            pthread_cond_destroy(&producer_cond);
        }
    
        //生产者线程：插入数据
        void safe_push(T data)
        { 
            pthread_mutex_lock(&lock);
            while(safe_queue.size() >= capacity)
            { 
                pthread_cond_wait(&producer_cond,&lock);
            }
            safe_queue.push(data);
            pthread_mutex_unlock(&lock);
            pthread_cond_signal(&consumer_cond);
        }
    
        //消费者线程：取出数据
        T safe_pop()
        { 
            pthread_mutex_lock(&lock);
            while(safe_queue.empty())
            { 
                pthread_cond_wait(&consumer_cond,&lock);
            }
            T data = safe_queue.front();
            safe_queue.pop();
            pthread_mutex_unlock(&lock);
            pthread_cond_signal(&producer_cond);
            return data;
        }
        private:
        queue<T> safe_queue;
        size_t capacity;  //设置队列中最大存储量
    
        pthread_mutex_t lock; //保证队列互斥的互斥锁
    
        //保证生产者线程与消费者线程同步的条件变量
        pthread_cond_t consumer_cond;
        pthread_cond_t producer_cond;
    };
    
    // 消费者线程：从 线程安全的队列 中一直 取出数据
    void* consumer_task(void* arg)
    { 
        BlockQueue<int> *safe_queue = (BlockQueue<int>*)arg;
    
        while(1)
        { 
            int data = safe_queue->safe_pop();
            printf("consumer[%p]: %d\n",pthread_self(),data);
        }
        return NULL;
    }
    // 生产者线程：从 线程安全的队列 中一直 插入数据
    void* producer_task(void* arg)
    { 
        BlockQueue<int> *safe_queue = (BlockQueue<int>*)arg;
        int data = 0;
        while(1)
        { 
            safe_queue->safe_push(data);
            printf("producer[%p] : %d\n",pthread_self(),data);
            data++;
        }
        return NULL;
    }
    
    int main()
    { 
        BlockQueue<int> *safe_queue = new BlockQueue<int>();
    
        pthread_t consumer_thread[THREAD_COUNT],producer_thread[THREAD_COUNT];
        for(int i = 0; i < THREAD_COUNT; i++)
        { 
            int ret_consumer = pthread_create(&consumer_thread[i],NULL,consumer_task,(void*)safe_queue);
            int ret_prodecer = pthread_create(&producer_thread[i],NULL,producer_task,(void*)safe_queue);
            if(ret_consumer < 0 || ret_prodecer)
            { 
                perror("pthread_create");
                return -1;
            }
        }
    
        for(int i = 0; i < THREAD_COUNT; i++)
        { 
            pthread_join(consumer_thread[i],NULL);
            pthread_join(producer_thread[i],NULL);
        }
    
        return 0;
    }

## 方法二：信号量模拟实现 ##

#include <stdio.h> 
     #include <iostream>
     #include <pthread.h>
     #include <semaphore.h>
     #include <vector>
     #include <unistd.h>
     using namespace std;
    
     /* 线程安全的队列：封装vector 1.读写下标的计算 pos = (pos + 1) % 数组大小 2.如何实现线程安全？ 互斥: 一个信号量，sem_t lock; sem_init(&lock,0,1); 同步: 两个信号量 生产者信号量：sem_t producer_sem; sem_init(&producer_sem, 0, 数组大小) 消费者信号量：sem_t consumer_sem; sem_init(&consumer_sem, 0, 0) */
     
     #define CAPACITY 4
     #define THREAD_COUNT 4
     
     template<class T>
    class BlockQueue{ 
         public:
         BlockQueue():safe_queue(CAPACITY)
         { 
             capacity = CAPACITY;
             sem_init(&lock, 0, 1);
             sem_init(&producer_sem, 0, capacity);
             sem_init(&consumer_sem, 0, 0);
             pos_read = pos_write = 0;
         }
         ~BlockQueue()
         { 
             sem_destroy(&lock);
             sem_destroy(&consumer_sem);
             sem_destroy(&producer_sem);
         }
    
         void push(T data)
         { 
             sem_wait(&producer_sem);
             sem_wait(&lock);
    
             safe_queue[pos_write] = data;
             pos_write = (pos_write + 1) % capacity;
    
             sem_post(&lock);
             sem_post(&consumer_sem);
         }
         T pop()
         { 
             sem_wait(&consumer_sem);
             sem_wait(&lock);
    
             T data = safe_queue[pos_read];
             pos_read = (pos_read + 1) % capacity;
    
             sem_post(&lock);
             sem_post(&producer_sem);
    
             return data;
         }
    
         private:
         vector<T> safe_queue;
         size_t capacity;
         sem_t lock, producer_sem, consumer_sem;
    
         size_t pos_write;
         size_t pos_read;
     };
    
    void* consumer_task(void* arg)
    { 
        BlockQueue<int>* p = (BlockQueue<int>*)arg;
    
        while(1)
        { 
            int data = p->pop();
            printf("consumer:[%p],I get :%d\n",pthread_self(),data);
            sleep(1);
        }
        return NULL;
    }
    void* producer_task(void* arg)
    { 
        BlockQueue<int>* p = (BlockQueue<int>*)arg;
    
        int data = 0;
        while(1)
        { 
            p->push(data);
            printf("producer:[%p],I put :%d\n",pthread_self(),data);
            data++;
            sleep(1);
        }
        return NULL;
    }
     
    int main()
    { 
        BlockQueue<int> *p_safe_queue = new BlockQueue<int>();
        pthread_t consumer_thread[THREAD_COUNT], producer_thread[THREAD_COUNT];
        for(int i = 0; i < THREAD_COUNT; i++)
        { 
            int ret_c = pthread_create(&consumer_thread[i],NULL,consumer_task,(void*)p_safe_queue);
            int ret_p = pthread_create(&producer_thread[i],NULL,producer_task,(void*)p_safe_queue);
            if(ret_c < 0 || ret_p < 0)
            { 
                perror("pthread_create");
                return -1;
            }
        }
        for(int i = 0; i < THREAD_COUNT; i++)
        { 
            pthread_join(consumer_thread[i],NULL);
            pthread_join(producer_thread[i],NULL);
        }
    
        return 0;
    }