生产者.cpp

生产者消费者问题

#include   <windows.h>   
#include   <iostream>   
    
  const   unsigned   short   SIZE_OF_BUFFER   =   10;   //缓冲区长度   
  unsigned   short   ProductID   =   0;         //产品号   
  unsigned   short   ConsumeID   =   0;         //将被消耗的产品号   
  unsigned   short   in   =   0;             //产品进缓冲区时的缓冲区下标   
  unsigned   short   out   =   0;             //产品出缓冲区时的缓冲区下标   
    
  int   g_buffer[SIZE_OF_BUFFER];         //缓冲区是个循环队列   
  bool   g_continue   =   true;             //控制程序结束   
  HANDLE   g_hMutex;               //用于线程间的互斥   
  HANDLE   g_hFullSemaphore;           //当缓冲区满时迫使生产者等待   
  HANDLE   g_hEmptySemaphore;           //当缓冲区空时迫使消费者等待   
    
  DWORD   WINAPI   Producer(LPVOID);         //生产者线程   
  DWORD   WINAPI   Consumer(LPVOID);         //消费者线程   
    
    //生产一个产品。简单模拟了一下，仅输出新产品的ID号   
  void   Produce()   
  {   
          std::cerr   <<   "Producing   "   <<   ++ProductID   <<   "   ...   ";   
          std::cerr   <<   "Succeed"   <<   std::endl;   
  }   
    
  //把新生产的产品放入缓冲区   
  void   Append()   
  {   
          std::cerr   <<   "Appending   a   product   ...   ";   
          g_buffer[in]   =   ProductID;   
          in   =   (in+1)%SIZE_OF_BUFFER;   
          std::cerr   <<   "Succeed"   <<   std::endl;   
    
          //输出缓冲区当前的状态   
          for   (int   i=0;i<SIZE_OF_BUFFER;++i){   
                  std::cout   <<   i   <<":   "   <<   g_buffer[i];   
                  if   (i==in)   std::cout   <<   "   <--   生产";   
                  if   (i==out)   std::cout   <<   "   <--   消费";   
                  std::cout   <<   std::endl;   
          }   
  }   
    
  //从缓冲区中取出一个产品   
  void   Take()   
  {   
          std::cerr   <<   "Taking   a   product   ...   ";   
          ConsumeID   =   g_buffer[out];   
          out   =   (out+1)%SIZE_OF_BUFFER;   
          std::cerr   <<   "Succeed"   <<   std::endl;   
    
          //输出缓冲区当前的状态   
          for   (int   i=0;i<SIZE_OF_BUFFER;++i){   
                  std::cout   <<   i   <<":   "   <<   g_buffer[i];   
                  if   (i==in)   std::cout   <<   "   <--   生产";   
                  if   (i==out)   std::cout   <<   "   <--   消费";   
                  std::cout   <<   std::endl;   
          }   
  }   
    
  //消耗一个产品   
  void   Consume()   
  {   
          std::cerr   <<   "Consuming   "   <<   ConsumeID   <<   "   ...   ";   
          std::cerr   <<   "Succeed"   <<   std::endl;   
  }  
  
    //生产者   
  DWORD     WINAPI   Producer(LPVOID   lpPara)   
  {   
          while(g_continue){   
                  WaitForSingleObject(g_hFullSemaphore,INFINITE);   
                  WaitForSingleObject(g_hMutex,INFINITE);   
                  Produce();   
                  Append();   
                  Sleep(1500);   
                  ReleaseMutex(g_hMutex);   
                  ReleaseSemaphore(g_hEmptySemaphore,1,NULL);   
          }   
          return   0;   
  }   
    
  //消费者   
  DWORD     WINAPI   Consumer(LPVOID   lpPara)   
  {   
          while(g_continue){   
                  WaitForSingleObject(g_hEmptySemaphore,INFINITE);   
                  WaitForSingleObject(g_hMutex,INFINITE);   
                  Take();   
                  Consume();   
                  Sleep(1500);   
                  ReleaseMutex(g_hMutex);   
                  ReleaseSemaphore(g_hFullSemaphore,1,NULL);   
          }   
          return   0;   
  }   
    
  int   main()   
  {   
          //创建各个互斥信号   
          g_hMutex   =   CreateMutex(NULL,FALSE,NULL);   
          g_hFullSemaphore   =   CreateSemaphore(NULL,SIZE_OF_BUFFER-1,SIZE_OF_BUFFER-1,NULL);   
          g_hEmptySemaphore   =   CreateSemaphore(NULL,0,SIZE_OF_BUFFER-1,NULL);   
    
          //调整下面的数值，可以发现，当生产者个数多于消费者个数时，   
          //生产速度快，生产者经常等待消费者；反之，消费者经常等待     
          const   unsigned   short   PRODUCERS_COUNT   =   3;     //生产者的个数   
          const   unsigned   short   CONSUMERS_COUNT   =   1;     //消费者的个数   
    
          //总的线程数   
          const   unsigned   short   THREADS_COUNT   =   PRODUCERS_COUNT+CONSUMERS_COUNT;   
    
          HANDLE   hThreads[PRODUCERS_COUNT];   //各线程的handle   
          DWORD   producerID[CONSUMERS_COUNT];   //生产者线程的标识符   
          DWORD   consumerID[THREADS_COUNT];   //消费者线程的标识符   
    
          //创建生产者线程   
          for   (int   i=0;i<PRODUCERS_COUNT;++i){   
                  hThreads[i]=CreateThread(NULL,0,Producer,NULL,0,&producerID[i]);   
                  if   (hThreads[i]==NULL)   return   -1;   
          }   
          //创建消费者线程   
          for   (int   j=0;j<CONSUMERS_COUNT;++j){   
                  hThreads[PRODUCERS_COUNT+j]=CreateThread(NULL,0,Consumer,NULL,0,&consumerID[j]);   
                  if   (hThreads[j]==NULL)   return   -1;   
          }   
    
          while(g_continue){   
                  if(getchar()){   //按回车后终止程序运行   
                          g_continue   =   false;   
                  }   
          }   
    
          return   0;   
  }