//------------------------------------------------------------------------
// Filename:
//     ProducerConsumer.cpp
// PROGRAM DESCRIPTION
//     Class implementation file for producer and consumer thread class. 
//     This program uses Hoare style monitor.
//------------------------------------------------------------------------

#include <iostream.h>
#include "ThreadClass.h"
#include "ProducerConsumer-mon.h"

//------------------------------------------------------------------------
// BufferMonitor::BufferMonitor()
//      constructor 
//------------------------------------------------------------------------

BufferMonitor::BufferMonitor(char* Name)
              :Monitor(Name, HOARE), NotFull("Notfull"),
               NotEmpty("NotEmpty") 
{
     NumberOfItems = 0;                 // no data items yet
     In = Out = 0 ;                 
};

//------------------------------------------------------------------------
// BufferMonitor::Put(Item_t item)
//      Add 'item' into the buffer
//------------------------------------------------------------------------

void BufferMonitor::Put(Item_t item)
{
     MonitorBegin();                       
     if (NumberOfItems == BUFFER_SIZE)  // buffer is full
          NotFull.Wait();
     Buffer[In] = item;                 // add item into the buffer       
     In = (In + 1) % BUFFER_SIZE;       // advance input pointer
     NumberOfItems++;                    // have one more item
     NotEmpty.Signal();                 // release a waiting consumers
     MonitorEnd();                      
}

//------------------------------------------------------------------------
// BufferMonitor::Get(Item_t *item)
//      Retrieve an item from the buffer
//------------------------------------------------------------------------

void BufferMonitor::Get(Item_t *item)
{
     MonitorBegin();                      
     if (NumberOfItems == 0)            // buffer is empty
          NotEmpty.Wait();
     *item = Buffer[Out];               // retrieve data
     Out = (Out + 1) % BUFFER_SIZE;     // advance out pointer
     NumberOfItems--;                   // have one less item
     NotFull.Signal();                  // release a waiting producer 
     MonitorEnd();                          
}

// end of ProducerConsumer-mon.cpp