转载一份C++线程池的代码，非常实用

 

转载一份C++线程池的代码，非常实用 .

分类： c++ 2012-12-31 10:48  174人阅读  评论(0)  收藏  举报

c++ C++ 工作

 #ifndef _ThreadPool_H_
 #define _ThreadPool_H_
 #pragma warning(disable: 4530)
 #pragma warning(disable: 4786)
 #include <cassert>
 #include <vector>
 #include <queue>
 #include <windows.h>

 using namespace std;

 class ThreadJob  //工作基类
 {
 public:
   //供线程池调用的虚函数
   virtual void DoJob(void *pPara) = 0;
 };
 class ThreadPool
 {
 public:
   //dwNum 线程池规模
   ThreadPool(DWORD dwNum = 4) : _lThreadNum(0), _lRunningNum(0)
   {
     InitializeCriticalSection(&_csThreadVector);
     InitializeCriticalSection(&_csWorkQueue);
     _EventComplete = CreateEvent(0, false, false, NULL);
     _EventEnd = CreateEvent(0, true, false, NULL);
     _SemaphoreCall = CreateSemaphore(0, 0,  0x7FFFFFFF, NULL);
     _SemaphoreDel =  CreateSemaphore(0, 0,  0x7FFFFFFF, NULL);
     assert(_SemaphoreCall != INVALID_HANDLE_VALUE);
     assert(_EventComplete != INVALID_HANDLE_VALUE);
     assert(_EventEnd != INVALID_HANDLE_VALUE);
     assert(_SemaphoreDel != INVALID_HANDLE_VALUE);
     AdjustSize(dwNum <= 0 ? 4 : dwNum);
   }
   ~ThreadPool()
   {
     DeleteCriticalSection(&_csWorkQueue);
     CloseHandle(_EventEnd);
     CloseHandle(_EventComplete);
     CloseHandle(_SemaphoreCall);
     CloseHandle(_SemaphoreDel);

     vector<ThreadItem*>::iterator iter;
     for(iter = _ThreadVector.begin(); iter != _ThreadVector.end(); iter++)
     {
       if(*iter)
         delete *iter;
     }
     DeleteCriticalSection(&_csThreadVector);
   }
   //调整线程池规模
   int AdjustSize(int iNum)
   {
     if(iNum > 0)
     {
       ThreadItem *pNew;
       EnterCriticalSection(&_csThreadVector);
       for(int _i=0; _i<iNum; _i++)
       {
         _ThreadVector.push_back(pNew = new ThreadItem(this));
         assert(pNew);
         pNew->_Handle = CreateThread(NULL, 0, DefaultJobProc, pNew, 0, NULL);
         // set priority
         SetThreadPriority(pNew->_Handle, THREAD_PRIORITY_BELOW_NORMAL);
         assert(pNew->_Handle);
       }
       LeaveCriticalSection(&_csThreadVector);
     }
     else
     {
       iNum *= -1;
       ReleaseSemaphore(_SemaphoreDel,  iNum > _lThreadNum ? _lThreadNum : iNum, NULL);
     }
     return (int)_lThreadNum;
   }
   //调用线程池
   void Call(void (*pFunc)(void  *), void *pPara = NULL)
   {
     assert(pFunc);
     EnterCriticalSection(&_csWorkQueue);
     _JobQueue.push(new JobItem(pFunc, pPara));
     LeaveCriticalSection(&_csWorkQueue);
     ReleaseSemaphore(_SemaphoreCall, 1, NULL);
   }
   //调用线程池
   inline void Call(ThreadJob * p, void *pPara = NULL)
   {
     Call(CallProc, new CallProcPara(p, pPara));
   }
   //结束线程池, 并同步等待
   bool EndAndWait(DWORD dwWaitTime = INFINITE)
   {
     SetEvent(_EventEnd);
     return WaitForSingleObject(_EventComplete, dwWaitTime) == WAIT_OBJECT_0;
   }
   //结束线程池
   inline void End()
   {
     SetEvent(_EventEnd);
   }
   inline DWORD Size()
   {
     return (DWORD)_lThreadNum;
   }
   inline DWORD GetRunningSize()
   {
     return (DWORD)_lRunningNum;
   }
   bool IsRunning()
   {
     return _lRunningNum > 0;
   }
 protected:
   //工作线程
   static DWORD WINAPI DefaultJobProc(LPVOID lpParameter = NULL)
   {
     ThreadItem *pThread = static_cast<ThreadItem*>(lpParameter);
     assert(pThread);
     ThreadPool *pThreadPoolObj = pThread->_pThis;
     assert(pThreadPoolObj);
     InterlockedIncrement(&pThreadPoolObj->_lThreadNum);
     HANDLE hWaitHandle[3];
     hWaitHandle[0] = pThreadPoolObj->_SemaphoreCall;
     hWaitHandle[1] = pThreadPoolObj->_SemaphoreDel;
     hWaitHandle[2] = pThreadPoolObj->_EventEnd;
     JobItem *pJob;
     bool fHasJob;

     for(;;)
     {
       DWORD wr = WaitForMultipleObjects(3, hWaitHandle, false, INFINITE);
       //响应删除线程信号
       if(wr == WAIT_OBJECT_0 + 1)
         break;

       //从队列里取得用户作业
       EnterCriticalSection(&pThreadPoolObj->_csWorkQueue);
       if(fHasJob = !pThreadPoolObj->_JobQueue.empty())
       {
         pJob = pThreadPoolObj->_JobQueue.front();
         pThreadPoolObj->_JobQueue.pop();
         assert(pJob);
       }
       LeaveCriticalSection(&pThreadPoolObj->_csWorkQueue);
       //受到结束线程信号 确定是否结束线程(结束线程信号 && 是否还有工作)
       if(wr == WAIT_OBJECT_0 + 2 && !fHasJob)
         break;
       if(fHasJob && pJob)
       {
         InterlockedIncrement(&pThreadPoolObj->_lRunningNum);
         pThread->_dwLastBeginTime = GetTickCount();
         pThread->_dwCount++;
         pThread->_fIsRunning = true;
         pJob->_pFunc(pJob->_pPara); //运行用户作业
         delete pJob;
         pThread->_fIsRunning = false;
         InterlockedDecrement(&pThreadPoolObj->_lRunningNum);
       }
     }
     //删除自身结构
     EnterCriticalSection(&pThreadPoolObj->_csThreadVector);
     pThreadPoolObj->_ThreadVector.erase(find(pThreadPoolObj->_ThreadVector.begin(), pThreadPoolObj->_ThreadVector.end(), pThread));
     LeaveCriticalSection(&pThreadPoolObj->_csThreadVector);
     delete pThread;
     InterlockedDecrement(&pThreadPoolObj->_lThreadNum);
     if(!pThreadPoolObj->_lThreadNum)  //所有线程结束
       SetEvent(pThreadPoolObj->_EventComplete);
     return 0;
   }
   //调用用户对象虚函数
   static void CallProc(void *pPara)
   {
     CallProcPara *cp = static_cast<CallProcPara *>(pPara);
     assert(cp);
     if(cp)
     {
       cp->_pObj->DoJob(cp->_pPara);
       delete cp;
     }
   }
   //用户对象结构
   struct CallProcPara
   {
     ThreadJob* _pObj;//用户对象
     void *_pPara;//用户参数
     CallProcPara(ThreadJob* p, void *pPara) : _pObj(p), _pPara(pPara) { };
   };
   //用户函数结构
   struct JobItem
   {
     void (*_pFunc)(void  *);//函数
     void *_pPara; //参数
     JobItem(void (*pFunc)(void  *) = NULL, void *pPara = NULL) : _pFunc(pFunc), _pPara(pPara) { };
   };
   //线程池中的线程结构
   struct ThreadItem
   {
     HANDLE _Handle; //线程句柄
     ThreadPool *_pThis;  //线程池的指针
     DWORD _dwLastBeginTime; //最后一次运行开始时间
     DWORD _dwCount; //运行次数
     bool _fIsRunning;
     ThreadItem(ThreadPool *pthis) : _pThis(pthis), _Handle(NULL), _dwLastBeginTime(0), _dwCount(0), _fIsRunning(false) { };
     ~ThreadItem()
     {
       if(_Handle)
       {
         CloseHandle(_Handle);
         _Handle = NULL;
       }
     }
   };

   std::queue<JobItem *> _JobQueue;  //工作队列
   std::vector<ThreadItem *>  _ThreadVector; //线程数据
   CRITICAL_SECTION _csThreadVector, _csWorkQueue; //工作队列临界, 线程数据临界
   HANDLE _EventEnd, _EventComplete, _SemaphoreCall, _SemaphoreDel;//结束通知, 完成事件, 工作信号， 删除线程信号
   long _lThreadNum, _lRunningNum; //线程数, 运行的线程数
 };
 #endif //_ThreadPool_H_

转载自  http://blog.csdn.net/pjchen/archive/2004/11/06/170606.aspx

基本上是拿来就用了，对WIN32 API不熟，但对线程池的逻辑还是比较熟的，认为这个线程池写得很清晰，我拿来用在一个多线程下载的模块中。很实用的东东。

调用方法

void threadfunc(void *p)

{

     YourClass* yourObject = (YourClass*)    p;

 //...
}
 ThreadPool tp;
 for(i=0; i<100; i++)
  tp.Call(threadfunc);

ThreadPool tp(20);//20为初始线程池规模

 tp.Call(threadfunc, lpPara);
     

使用时注意几点：

1.  ThreadJob  没什么用，直接写线程函数吧。 

2. 线程函数（threadfunc）的入口参数void* 可以转成自定义的类型对象，这个对象可以记录下线程运行中的数据，并设置线程当前状态，以此与线程进行交互。

3. 线程池有一个EndAndWait函数，用于让线程池中所有计算正常结束。有时线程池中的一个线程可能要运行很长时间，怎么办？可以通过线程函数threadfunc的入口参数对象来处理，比如：

class YourClass {

  int cmd; // cmd = 1是上线程停止计算，正常退出。

};

threadfunc(void* p) {

  YourClass* yourObject = (YourClass*)p;

  while (true) {

    // do some calculation

    if (yourClass->cmd == 1)

      break;

  }

}

在主线程中设置yourClass->cmd = 1，该线程就会自然结束。

很简洁通用的线程池实现。