/******************************************************************************
* FILE: experiment-x2.c
* DESCRIPTION:
*   Demontrating consumer producer with threads which are synchronized
*   One mutex-variable is used to support thread synchronisation
*
* LAST REVISED: 25/08/03 Florian Weizenegger
******************************************************************************/

#include <pthread.h>
#include <sys/time.h>		/* for gettimeofday() */
#include <unistd.h>		/* for gettimeofday() */
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/sem.h>            /* for semget(), semop(), semctl() */

#define NUM_THREADS	45
#define SIZEOFBUFFER    8000
#define NO_OF_ITERATIONS 10000

/* Para uso dos semafaros */
#define NUMERO_DE_SEM SIZEOFBUFFER
#define CHAVE_DE_SEM 0x1234
#define PERMISSAO_SEM 0666
struct sembuf sem_ocupadas[1];
struct sembuf sem_livres[1];

	
pthread_t consumers[NUM_THREADS];
pthread_t producers[NUM_THREADS];

pthread_mutex_t mutex_p, mutex_c;

int buffer[SIZEOFBUFFER];
int i1=0, i2=0, id;

void myadd(int toAdd)
{
	i1 = (i1+1) % SIZEOFBUFFER;
    buffer[i1] = toAdd;
}

void myremove()
{
	buffer [i2];
	i2 = (i2+1) % SIZEOFBUFFER;
}


//Producer adds NO_OF_ITERATIONS times the value 10
//to the buffer
void *produce(void *threadid)
{
  int i = 0;
  int sum = 0;
  int ret = 0;

  printf("Producer #%d started...\n", threadid);

  while (i < NO_OF_ITERATIONS)
  {
    
	if( semop( id, sem_livres, 1 ) == -1 )
    {
		fprintf(stderr,"chamada semop() falhou, impossivel fechar o semaforo!");
        exit(1);
	}
	pthread_mutex_lock (&mutex_p);
    
	myadd(10);
    i++;
    sum += 10;
    
	if( semop( id, sem_ocupadas, 1 ) == -1 )
    {
		fprintf(stderr,"chamada semop() falhou, impossivel fechar o semaforo!");
        exit(1);
	}
	
    pthread_mutex_unlock (&mutex_p);
  }
  
  printf("Producer #%d sum : %d\n", threadid, sum);
  pthread_exit(NULL);
}

//Consumer removes
void *consume(void *threadid)
{
  int i = 0;
  int sum = 0;
  int ret = 0;

  printf("Consumer #%d started...\n", threadid);

  while (i < NO_OF_ITERATIONS)
  {
    
	if( semop( id, sem_ocupadas, 1 ) == -1 )
    {
		fprintf(stderr,"chamada semop() falhou, impossivel fechar o semaforo!");
        exit(1);
	}
	pthread_mutex_lock (&mutex_c);
    
	myremove();
    i++;
    sum += ret;
    
	if( semop( id, sem_livres, 1 ) == -1 )
    {
		fprintf(stderr,"chamada semop() falhou, impossivel fechar o semaforo!");
        exit(1);
	}
	pthread_mutex_unlock (&mutex_c);
  }
  
  printf("Consumer #%d sum : %d\n", threadid, sum);
  pthread_exit(NULL);
}

int main(int argc, char *argv[])
{
  int tc, tp, status, i, rc;
  float delta;
  struct timeval start_time;
  struct timeval stop_time;

  gettimeofday( &start_time, NULL );

  //init mutex
  pthread_mutex_init(&mutex_p, NULL);
  pthread_mutex_init(&mutex_c, NULL);
    
	/*
	 * Destrancar semapharo
	 */
	sem_ocupadas[0].sem_op = -1;
	sem_ocupadas[0].sem_num = 0;		/* numero do semapharo */
	sem_ocupadas[0].sem_flg = 0;
	
	sem_livres[0].sem_op = 1;
	sem_livres[0].sem_num = 0;		/* numero do semapharo */
	sem_livres[0].sem_flg = 0;
  
	/*
	 * Criacao do semapharo
	*/
	if( (id = semget(CHAVE_DE_SEM, 1, IPC_CREAT |0666 )) == -1 )
	{
		perror("\n Erro na requisicao de criacao do semapharo - semget \n");
		fprintf(stderr,"Erro na requisicao de criacao do semapharo - semget");
		exit(1);
	}
	if( semop(id, sem_livres, 1) == -1)
	{
		fprintf(stderr,"");
		perror("\n Erro ao usar o semapharo na chamada semop\n");
		exit(1);
	}
	
	
  for (i=0;i<NUM_THREADS;i++) {
    tc = pthread_create(&consumers[i], NULL, consume, (void *)i+1);
    if (tc) {
      printf("ERROR: couldn't create consumer thread\n");
      exit(-1);
    }
    tp = pthread_create(&producers[i], NULL, produce, (void *)i+1);
    if (tp) {
      printf("ERROR: couldn't create producer thread\n");
      exit(-1);
    }
  }

  for(i=0;i < NUM_THREADS;i++) {
    rc = pthread_join(consumers[i], (void **)&status);
    if (rc)
      {
	printf("ERROR; return code from pthread_join() is %d\n", rc);
	exit(-1);
      }
  }
  

  
  pthread_mutex_destroy(&mutex_p);
  pthread_mutex_destroy(&mutex_c);

  gettimeofday( &stop_time, NULL );
  
  //for(i=0; i<SIZEOFBUFFER; i++)
	//  printf("\n%d -> %d", i, buffer[i]);
	
  
  delta = (float)(stop_time.tv_sec  - start_time.tv_sec);
  delta += (stop_time.tv_usec - start_time.tv_usec)/(float)1000000;
  printf("\nTotal time : %.10f sec\n\n", delta);

  pthread_exit(NULL);
 
  if( semctl( id, 0, IPC_RMID, 0) != 0 )
	{
		fprintf(stderr,"Impossivel remover o semaforo!\n");
		exit(1);
	}
}