ACE/examples/APG/ThreadSafety/Atomic_Op.cpp

   1 #include "ace/Synch.h"
   2 #include "ace/Task.h"
   3 #include "ace/Log_Msg.h"
   4 #include "ace/Atomic_Op.h"
   5
   6 #if defined(RUNNING_ON_UNSAFE_MULTIPROCESSOR)
   7 // Listing 1 code/ch14
   8 typedef ACE_Atomic_Op<ACE_Thread_Mutex, unsigned int> SafeUInt;
   9 // Listing 1
  10 // Listing 2 code/ch14
  11 typedef ACE_Atomic_Op<ACE_Thread_Mutex, int> SafeInt;
  12 // Listing 2
  13 #else
  14 typedef ACE_Atomic_Op<ACE_Null_Mutex, unsigned int> SafeUInt;
  15 typedef ACE_Atomic_Op<ACE_Null_Mutex, int> SafeInt;
  16 #endif /* RUNNING_ON_UNSAFE_MULTIPROCESSOR) */
  17
  18 static const unsigned int Q_SIZE = 2;
  19 static const int MAX_PROD = 10;
  20
  21 // Listing 3 code/ch14
  22 class Producer : public ACE_Task_Base
  23 {
  24 public:
  25   Producer (int *buf, SafeUInt &in, SafeUInt &out)
  26     : buf_(buf), in_(in), out_(out)
  27   { }
  28
  29   int svc ()
  30   {
  31     SafeInt itemNo = 0;
  32     while (1)
  33       {
  34         // Busy wait.
  35         do
  36           { }
  37         while (in_.value () - out_.value () == Q_SIZE);
  38
  39         itemNo++;
  40         buf_[in_.value () % Q_SIZE] = itemNo.value ();
  41         in_++;
  42
  43         ACE_DEBUG ((LM_DEBUG, ACE_TEXT ("Produced %d\n"),
  44                     itemNo.value ()));
  45
  46         if (check_termination (itemNo.value ()))
  47           break;
  48       }
  49
  50     return 0;
  51   }
  52
  53   int check_termination (int item)
  54   {
  55     return (item == MAX_PROD);
  56   }
  57
  58 private:
  59   int * buf_;
  60   SafeUInt& in_;
  61   SafeUInt& out_;
  62 };
  63
  64 class Consumer : public ACE_Task_Base
  65 {
  66 public:
  67   Consumer (int *buf, SafeUInt &in, SafeUInt& out)
  68     : buf_(buf), in_(in), out_(out)
  69   { }
  70
  71   int svc ()
  72   {
  73     while (1)
  74       {
  75         int item;
  76
  77         // Busy wait.
  78         do
  79           { }
  80         while (in_.value () - out_.value () == 0);
  81
  82         item = buf_[out_.value () % Q_SIZE];
  83         out_++;
  84
  85         ACE_DEBUG ((LM_DEBUG, ACE_TEXT ("Consumed %d\n"),
  86                     item));
  87
  88         if (check_termination (item))
  89           break;
  90       }
  91
  92     return 0;
  93   }
  94
  95   int check_termination (int item)
  96   {
  97     return (item == MAX_PROD);
  98   }
  99
 100 private:
 101   int * buf_;
 102   SafeUInt& in_;
 103   SafeUInt& out_;
 104 };
 105 // Listing 3
 106
 107 // Listing 4 code/ch14
 108 int ACE_TMAIN (int, ACE_TCHAR *[])
 109 {
 110   int shared_buf[Q_SIZE];
 111   SafeUInt in = 0;
 112   SafeUInt out = 0;
 113
 114   Producer producer (shared_buf, in, out);
 115   Consumer consumer (shared_buf, in, out);
 116
 117   producer.activate();
 118   consumer.activate();
 119   producer.wait();
 120   consumer.wait();
 121
 122   return 0;
 123 }
 124 // Listing 4
 125