#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <stdlib.h>
#include <pthread.h>
#include<semaphore.h>

#define TRUE 1
#define FALSE 0
 
int places=10;
sem_t evt_in,evt_out,evt_maj;
int fin=FALSE;
pthread_mutex_t mutex_pl;
pthread_cond_t cond_places ;

void * t_keyboard (void *arg)
{
char res;
 while (fin!=TRUE)
{
 res=getchar();
 //fflush(stdin);
//printf ("user input=%c\n",res);
 if(res=='f')
{
    fin=TRUE;
	
}
else if  ( res=='e')
{
          sem_post(&evt_in);
		 }
 else if (res=='s')
{
sem_post(&evt_out);
		 }
}
}
void * t_enter (void *arg){
     while (fin!=TRUE){
	 //printf("ok t enter\n");
       sem_wait(&evt_in);
	  // printf("ok t enter\n");
       pthread_mutex_lock(&mutex_pl);
       if (places==0){
         pthread_cond_wait(&cond_places, &mutex_pl);
     }
       printf(" barrier opening(IN)");
       
     places = places -1;
       sem_post(&evt_maj);
    // printf(" ok t enter\n");
       pthread_mutex_unlock(&mutex_pl);
     }
   }
   
void * t_exit (void *arg){
 
while (fin!=TRUE){
       sem_wait(&evt_out);
       pthread_mutex_lock(&mutex_pl);
       if (places==0){
         pthread_cond_wait(&cond_places, &mutex_pl);
     }
       printf("barrier opening IN");
     places = places +1;
       sem_post(&evt_maj);
       pthread_mutex_unlock(&mutex_pl);
     }
   }
      
void * t_display (void *arg){
 
while (fin!= TRUE) {
      sem_wait(&evt_maj);
      pthread_mutex_lock(&mutex_pl);
      printf ("places = %d\n",places);
      pthread_mutex_unlock(&mutex_pl);
      }
}

int main()
{

pthread_t thread_keyboard,thread_enter,thread_display,thread_exit;
int  ikeyboard,ienter,idisplay,iexit;
pthread_mutex_init(&mutex_pl,NULL);
pthread_cond_init(&cond_places,0);
sem_init(&evt_in,0,0);
sem_init(&evt_maj,0,0);

ikeyboard=pthread_create( &thread_keyboard, NULL,&t_keyboard,NULL);
ienter=pthread_create( &thread_enter, NULL,&t_enter,NULL);
iexit=pthread_create( &thread_exit, NULL,&t_exit,NULL);
idisplay=pthread_create( &thread_display, NULL,&t_display,NULL);

pthread_join( thread_keyboard, NULL);
pthread_join( thread_enter, NULL);
pthread_join( thread_exit, NULL);
pthread_join( thread_display, NULL);
 
exit(0);
}