/*
 * slowProdConCond.c++ Producer-Consumer Problem  
 *         one is slower than the other 
 * $ g++ -Wall slowProdCon.c++  -lpthread       
*/
#include <iostream>
using namespace std;
#include <stdlib.h>
#include <pthread.h>
#include "queuePth1.h"
#define DELAY 10000

int data;
int dataCount=0;


void *producer(void *);
void *consumer(void *);

pthread_mutex_t makeAtomic = PTHREAD_MUTEX_INITIALIZER;
pthread_cond_t cvF = PTHREAD_COND_INITIALIZER;  // added
pthread_cond_t cvE = PTHREAD_COND_INITIALIZER;  // added

int main(int count, char *vect[]) {
     pthread_t thID1, thID2; // thread ID
     int num;
    
     cout << "Enter number of data: ";
     cin >> num ;

     pthread_create(&thID1, NULL, producer, (void *)&num);
     pthread_create(&thID2, NULL, consumer, (void *)&num);
     pthread_join(thID1, NULL);    
     pthread_join(thID2, NULL);
     return 0;
}

void *producer(void *par){
     int num = *(int *)par;

     for(int i=1; i<=num; ) {
         pthread_mutex_lock(&makeAtomic);
	 cout << "P->  ";
	 while(dataCount == 1) // added
              pthread_cond_wait(&cvE, &makeAtomic);  
	 // if(dataCount==0){
            dataCount = 1;  
            data=i;
	    ++i;
	 // } 
	 pthread_cond_signal(&cvF);  // added
         pthread_mutex_unlock(&makeAtomic);
         // for(int j=0; j<DELAY; ++j); // Delay
     }
     pthread_exit(NULL);
}

void *consumer(void *par){
     int num = *(int *)par;

     for(int i=1; i<=num;){ 
         pthread_mutex_lock(&makeAtomic);
	 cout << "C<- ";
         while(dataCount == 0)   // added
               pthread_cond_wait(&cvF, &makeAtomic);
	 // if(dataCount==1){
            cout << "Data read: " << data << endl;
            dataCount=0;
	    ++i;
	 // }
	 pthread_cond_signal(&cvE);  // added
         pthread_mutex_unlock(&makeAtomic);
         for(int j=0; j<DELAY; ++j); // Delay
     }
     pthread_exit(NULL);
}