基于条件变量的消息队列 说明介绍

/*
 * BlockingQueue.h
 *
 *  Created on: Apr 19, 2013
 *      Author: archy_yu
 */

#ifndef BLOCKINGQUEUE_H_
#define BLOCKINGQUEUE_H_

#include <queue>
#include <pthread.h>

typedef void* CommonItem;

class BlockingQueue
{
public:
    BlockingQueue();

    virtual ~BlockingQueue();

    int peek(CommonItem &item);

    int append(CommonItem item);

private:

    pthread_mutex_t _mutex;

    pthread_cond_t _cond;

    std::queue<CommonItem> _read_queue;

    std::queue<CommonItem> _write_queue;

};

 
#endif /* BLOCKINGQUEUE_H_ */

/*
 * BlockingQueue.cpp
 *
 *  Created on: Apr 19, 2013
 *      Author: archy_yu
 */

#include "BlockingQueue.h"

BlockingQueue::BlockingQueue()
{
    pthread_mutex_init(&this->_mutex,NULL);
    pthread_cond_init(&this->_cond,NULL);
}

BlockingQueue::~BlockingQueue()
{
    pthread_mutex_destroy(&this->_mutex);
    pthread_cond_destroy(&this->_cond);
}

int BlockingQueue::peek(CommonItem &item)
{

    if( !this->_read_queue.empty() )
    {
        item = this->_read_queue.front();
        this->_read_queue.pop();
    }
    else
    {
        pthread_mutex_lock(&this->_mutex);

        while(this->_write_queue.empty())
        {
            pthread_cond_wait(&this->_cond,&this->_mutex);
        }

        while(!this->_write_queue.empty())
        {
            this->_read_queue.push(this->_write_queue.front());
            this->_write_queue.pop();
        }

        pthread_mutex_unlock(&this->_mutex);
    }

 
    return 0;
}

int BlockingQueue::append(CommonItem item)
{
    pthread_mutex_lock(&this->_mutex);
    this->_write_queue.push(item);
    pthread_cond_signal(&this->_cond);
    pthread_mutex_unlock(&this->_mutex);
    return 0;
}

BlockingQueue _queue;

void* process(void* arg)
{

    int i=0;
    while(true)
    {
        int *j = new int();
        *j = i;
        _queue.append((void *)j);
        i ++;
    }
    return NULL;
}

int main(int argc,char** argv)
{
    pthread_t pid;
    pthread_create(&pid,0,process,0);

    long long int start = get_os_system_time();
    int i = 0;
    while(true)
    {
        int* j = NULL;
        _queue.peek((void* &)j);

        i ++;

        if(j != NULL && (*j) == 100000)
        {
            long long int end = get_os_system_time();
            printf("consume %d\n",end - start);
            break;
        }
    }

    return 0;
}