// threadtest.cc 
//
// ASSIGNMENT 4: (02/01/08, RD)
// bounded buffer with 2 producer and 2 consumer threads

#include "copyright.h"
#include "system.h"
#include "synch.h"	// ASSIGNMENT 4

//----------------------------------------------------------------------
// bounded buffer
//----------------------------------------------------------------------

class Buffer		// ASSIGNMENT 4
{
public:
    Buffer(char *name, int size);	// constructor takes buffer size
    ~Buffer(void);			// destructor

    char Get(void);	// load a character
    void Put(char c);	// store a character

private:
    int isEmpty(void);	// check if buffer is empty
    int isFull(void);	// check if buffer is full
    char *BufferName;	// name (useful for debugging)
    int Size;		// size of the buffer
    char *Array;	// array to store characters in buffer
    int n;		// number of characters currently in buffer
    int PosGet;		// next position for Get()
    int PosPut;         // next position for Put()
};

Buffer::Buffer(char *name, int size)	// ASSIGNMENT 4
{
    BufferName = name;
    Size = size;
    Array = new char[size];
    n = 0;
    PosGet = 0;
    PosPut = 0;
}

Buffer::~Buffer(void)			// ASSIGNMENT 4
{
    delete[] Array;
}

char Buffer::Get(void)			// ASSIGNMENT 4
{
    char c;
    c = Array[PosGet];
    n--;
    PosGet = (PosGet+1) % Size;
    return c;
}

void Buffer::Put(char c)		// ASSIGNMENT 4
{
    Array[PosPut] = c;
    n++;
    PosPut = (PosPut+1) % Size;
}

int Buffer::isEmpty(void)		// ASSIGNMENT 4
{
    return(n == 0);
}

int Buffer::isFull(void)		// ASSIGNMENT 4
{
    return(n == Size);
}

// Buffer instantiation			// ASSIGNMENT 4

Buffer b("MyBuffer", 10);

// Consumer Thread			// ASSIGNMENT 4

void ConsumerThread(int id)
{
    while (1)
    {    printf("\t\t\tConsumer %d got a '%c'\n", id, b.Get());    
    }
}

// Producer Thread			// ASSIGNMENT 4

void ProducerThread(int id)
{
    static char *Text = "The quick brown fox jumps over the lazy dog.";
    char *p;
    p = Text;
    while (*p)
    {   b.Put(*p);
	printf("Producer %d put a '%c'\n", id, *p);    
	p++;
    }
}

//----------------------------------------------------------------------
// ThreadTest
//----------------------------------------------------------------------

void
ThreadTest()				// ASSIGNMENT 4
{
   DEBUG('t', "Entering consumer/producer example");

   // create consumer and producer threads
   Thread *cons1 = new Thread("Consumer1", 1);
   Thread *cons2 = new Thread("Consumer2", 2);
   Thread *prod1 = new Thread("Producer1", 1);
   Thread *prod2 = new Thread("Producer2", 2);

   cons1->Fork(ConsumerThread, 1);
   cons2->Fork(ConsumerThread, 2);
   prod1->Fork(ProducerThread, 1);
   prod2->Fork(ProducerThread, 2);

   // let this main thread terminate here
}