r_wp1.cpp

通过多线程模拟

#include<windows.h>
#include<fstream.h>
#include<stdio.h>
#include<string>
#include<conio.h>

//定义一些常量；
//本程序允许的最大临界区数；
#define MAX_BUFFER_NUM	10
//秒到微秒的乘法因子；
#define INTE_PER_SEC 1000
//本程序允许的生产和消费线程的总数；
#define MAX_THREAD_NUM 64

//定义一个结构，记录在测试文件中指定的每一个线程的参数
struct ThreadInfo
{
	int	serial;								//线程序列号
	char	entity;							    //是P还是C
	double	delay;							//线程延迟
	int	thread_request[MAX_THREAD_NUM]; 	//线程请求队列
	int	n_request;							//请求个数
};

//全局变量的定义

//临界区对象的声明,用于管理缓冲区的互斥访问；
CRITICAL_SECTION	PC_Critical[MAX_BUFFER_NUM];	
int	        Buffer_Critical[MAX_BUFFER_NUM]; //缓冲区声明，用于存放产品；
HANDLE    h_Thread[MAX_THREAD_NUM];	 //用于存储每个线程句柄的数组；
ThreadInfo	Thread_Info[MAX_THREAD_NUM];	 //线程信息数组；
HANDLE	empty_semaphore;					 //一个信号量；
HANDLE	h_mutex;							 //一个互斥量；
DWORD		n_Thread = 0;					     //实际的线程的数目；
DWORD		n_Buffer_or_Critical;			     //实际的缓冲区或者临界区的数目；
HANDLE	h_Semaphore[MAX_THREAD_NUM]; //生产者允许消费者开始消费的信号量；

//生产消费及辅助函数的声明
void  Produce(void *p);
void  Consume(void *p);	
bool  IfInOtherRequest(int);
int	  FindProducePositon();
int	  FindBufferPosition(int);

int    main(void)
{
	//声明所需变量；
	DWORD		wait_for_all;
	ifstream	inFile;
				
	//初始化缓冲区；
	for(int i=0;i< MAX_BUFFER_NUM;i++)
		Buffer_Critical[i] = -1;				
	//初始化每个线程的请求队列；
	for(int j=0;j<MAX_THREAD_NUM;j++){
		for(int k=0;k<MAX_THREAD_NUM;k++)
			Thread_Info[j].thread_request[k] = -1;
		Thread_Info[j].n_request = 0;
	}
	//初始化临界区；
	for(i =0;i< MAX_BUFFER_NUM;i++) 
		InitializeCriticalSection(&PC_Critical[i]);

	//打开输入文件，按照规定的格式提取线程等信息；
	inFile.open("test.txt");
	//从文件中获得实际的缓冲区的数目；
	inFile >> n_Buffer_or_Critical;
	inFile.get();
	printf("输入文件是:\n");
	//回显获得的缓冲区的数目信息；
	printf("%d \n",(int) n_Buffer_or_Critical);
	//提取每个线程的信息到相应数据结构中；
	while(inFile){
		inFile >> Thread_Info[n_Thread].serial;
		inFile >> Thread_Info[n_Thread].entity;
		inFile >> Thread_Info[n_Thread].delay;
		char c;
		inFile.get(c);
		while(c!='\n'&& !inFile.eof()){
		 inFile>> Thread_Info[n_Thread].thread_request[Thread_Info[n_Thread].n_request++];
		 inFile.get(c);	
		}
		n_Thread++;
	}  

	//回显获得的线程信息，便于确认正确性；	
	for(j=0;j<(int) n_Thread;j++){
		int    Temp_serial  = Thread_Info[j].serial;
		char   Temp_entity  = Thread_Info[j].entity;
		double Temp_delay   = Thread_Info[j].delay;
		printf(" \n thread%2d    %c    %f   ",Temp_serial,Temp_entity,Temp_delay);
		int Temp_request = Thread_Info[j].n_request;
		for(int k=0;k<Temp_request;k++)
			printf(" %d    ", Thread_Info[j].thread_request[k]);
		cout<<endl;
	}
	printf("\n\n");

 	//创建在模拟过程中几个必要的信号量
	empty_semaphore=CreateSemaphore(NULL,n_Buffer_or_Critical,n_Buffer_or_Critical,
								  "semaphore_for_empty");
	h_mutex	= CreateMutex(NULL,FALSE,"mutex_for_update");

	//下面这个循环用线程的ID号来为相应生产线程的产品读写时所
	//使用的同步信号量命名；
	for(j=0;j<(int)n_Thread;j++){  			
		std::string lp ="semaphore_for_produce_";
		int temp =j;
		while(temp){
		char c = (char)(temp%10);
		lp+=c;
		temp/=10;
		}
		h_Semaphore[j+1]=CreateSemaphore(NULL,0,n_Thread,lp.c_str());				
	}

	//创建生产者和消费者线程；
	for(i =0;i< (int) n_Thread;i++){
		if(Thread_Info[i].entity =='P')
			h_Thread[i]= CreateThread(NULL,0,(LPTHREAD_START_ROUTINE)(Produce),
									&(Thread_Info[i]),0,NULL);
		else
		   h_Thread[i]=CreateThread(NULL,0,(LPTHREAD_START_ROUTINE)(Consume),
								&(Thread_Info[i]),0,NULL);
	}

	//主程序等待各个线程的动作结束；
	wait_for_all = WaitForMultipleObjects(n_Thread,h_Thread,TRUE,-1);
	printf(" \n \nALL Producer and consumer have finished their work. \n");
	printf("Press any key to quit!\n");
	_getch();
	return 0;
}

//确认是否还有对同一产品的消费请求未执行；
bool IfInOtherRequest(int req)
{
	for(int i=0;i<n_Thread;i++)
		for(int j=0;j<Thread_Info[i].n_request;j++)
			if(Thread_Info[i].thread_request[j] == req)
				return TRUE;

	return FALSE;
}

//找出当前可以进行产品生产的空缓冲区位置；
int	FindProducePosition()
{
	int EmptyPosition;
	for (int i =0;i<n_Buffer_or_Critical;i++)
		if(Buffer_Critical[i] == -1){
			EmptyPosition = i;
			//用下面这个特殊值表示本缓冲区正处于被写状态；
			Buffer_Critical[i] = -2;
			break;
		}
	return  EmptyPosition;
}

//找出当前所需生产者生产的产品的位置；
int FindBufferPosition(int ProPos)
{
	int TempPos;
	for (int i =0 ;i<n_Buffer_or_Critical;i++)
		if(Buffer_Critical[i]==ProPos){
			TempPos = i;
			break;
		}
	return TempPos;
}

//生产者进程
void Produce(void *p)
{
	//局部变量声明；
	DWORD	wait_for_semaphore,wait_for_mutex,m_delay;
	int		m_serial;

	//获得本线程的信息；
	m_serial = ((ThreadInfo*)(p))->serial;
	m_delay  = (DWORD)(((ThreadInfo*)(p))->delay *INTE_PER_SEC);

	Sleep(m_delay);
	//开始请求生产
	printf("Producer %2d sends the produce require.\n",m_serial);

	//确认有空缓冲区可供生产，同时将空位置数empty减1；用于生产者和消费者的同步；
	wait_for_semaphore	=  WaitForSingleObject(empty_semaphore,-1);
						
	//互斥访问下一个可用于生产的空临界区，实现写写互斥；
	wait_for_mutex  = WaitForSingleObject(h_mutex,-1);
	int  ProducePos = FindProducePosition();
    	ReleaseMutex(h_mutex);

	//生产者在获得自己的空位置并做上标记后，以下的写操作在生产者之间可以并发；
	//核心生产步骤中，程序将生产者的ID作为产品编号放入，方便消费者识别;
	printf("Producer %2d begin  to produce at position %2d.\n",m_serial,ProducePos);
	Buffer_Critical[ProducePos] = m_serial;
	printf("Producer %2d finish producing :\n ",m_serial);
	printf("	 position[ %2d ]:%3d \n" ,ProducePos,Buffer_Critical[ProducePos]);
	//使生产者写的缓冲区可以被多个消费者使用，实现读写同步；
	ReleaseSemaphore(h_Semaphore[m_serial],n_Thread,NULL);
}

//消费者进程
void Consume(void * p)
{
	//局部变量声明；
	DWORD	wait_for_semaphore,m_delay;
	int	m_serial,m_requestNum;		       //消费者的序列号和请求的数目；
	int	m_thread_request[MAX_THREAD_NUM];//本消费线程的请求队列；
    
	//提取本线程的信息到本地；
	m_serial = ((ThreadInfo*)(p))->serial;
	m_delay  = (DWORD)(((ThreadInfo*)(p))->delay *INTE_PER_SEC);
	m_requestNum = ((ThreadInfo *)(p))->n_request;
	for (int i = 0;i<m_requestNum;i++)
		m_thread_request[i] = ((ThreadInfo*)(p))->thread_request[i];


	Sleep(m_delay);	
	//循环进行所需产品的消费
	for(i =0;i<m_requestNum;i++){   
		
	  //请求消费下一个产品
	  printf("Consumer %2d request to consume %2d product\n",m_serial,m_thread_request[i]);
	  //如果对应生产者没有生产，则等待；如果生产了,允许的消费者数目-1；实现了读写同步；
	  wait_for_semaphore=WaitForSingleObject(h_Semaphore[m_thread_request[i]],-1); 

	  //查询所需产品放到缓冲区的号		
	  int BufferPos=FindBufferPosition(m_thread_request[i]);	  
			
	  //开始进行具体缓冲区的消费处理，读和读在该缓冲区上仍然是互斥的；
	  //进入临界区后执行消费动作；并在完成此次请求后，通知另外的消费者本处请求已
	  //经满足；同时如果对应的产品使用完毕，就做相应处理；并给出相应动作的界面提
	  //示；该相应处理指将相应缓冲区清空，并增加代表空缓冲区的信号量；
	  EnterCriticalSection(&PC_Critical[BufferPos]);
	  printf("Consumer%2d begin to consume %2d product \n",m_serial,m_thread_request[i]);
 		  ((ThreadInfo*)(p))->thread_request[i] =-1;
	  if(!IfInOtherRequest(m_thread_request[i])){
		Buffer_Critical[BufferPos] = -1;//标记缓冲区为空；
		printf("Consumer%2d finish consuming %2d:\n ",m_serial,m_thread_request[i]);
		printf("	 position[ %2d ]:%3d \n" ,BufferPos,Buffer_Critical[BufferPos]);
		ReleaseSemaphore(empty_semaphore,1,NULL);
	  }		
	  else{
printf("Consumer %2d finish consuming product %2d\n ",m_serial,m_thread_request[i]);
	  }
//离开临界区
	  LeaveCriticalSection(&PC_Critical[BufferPos]);

	}
}