/* ----------------------------------------------------------------- */
/* PROGRAM  counter-1.c:                                             */
/*    This program creates a number of threads, each of which has a  */
/* critical section for increasing the value of shared counter.      */
/* ----------------------------------------------------------------- */

#include  <stdio.h>
#include  <stdlib.h>
#include  <thread.h>
#include  <synch.h>

#define   NO_THREADS    5                /* current, no more than 5  */

sema_t    Lock;                          /* the protecting semaphore */

int       Counter, Max_Run;              /* the shared counter       */

/* ----------------------------------------------------------------- */
/* FUNCTION  Counting():                                             */
/*    This function increases the shared counter Max_run times.      */
/* ----------------------------------------------------------------- */

void  *Counting(void *voidPTR)
{
     int   *intPTR = (int *) voidPTR;
     int   Name    = *intPTR;
     char  filler[20];
     int   i;

     for (i = 0; i < Name*2; i++)
          filler[i] = ' ';
     filler[i] = '\0';

     printf("%sThread %d started\n", filler, Name);
     for (i = 0; i < Max_Run; i++) {
          thr_yield();                   /* rest for unspecified time*/
          sema_wait(&Lock);              /* enter critical section   */
               Counter++;                /* do updating and printing */
               printf("%sThread %d reports: new counter value = %d\n",
                       filler, Name, Counter);
          sema_post(&Lock);              /* leaving critical section */
     }
     printf("%sThread %d ends\n", filler, Name);
     thr_exit(0);
}

/* ----------------------------------------------------------------- */
/*                           The main program                        */
/* ----------------------------------------------------------------- */

void  main(int  argc,  char *argv[])
{
     thread_t   ID[NO_THREADS];          /* thread IDs               */
     size_t     Status[NO_THREADS];      /* thread status            */
     int        Argument[NO_THREADS];    /* thread argument          */
     int        i;

     if (argc != 2) {
          printf("Use %s #-of-iterations\n", argv[0]);
          exit(0);
     }
     Max_Run = abs(atoi(argv[1]));

     printf("Parent started ...\n");

     Counter = 0;
     sema_init(&Lock, 1, USYNC_THREAD, (void *) NULL);  /* init sem. */

     printf("Parent is about to create %d threads\n", NO_THREADS);

     for (i = 0; i < NO_THREADS; i++) {  /* create all threads       */
          Argument[i] = i;
          thr_create(NULL, 0, Counting, (void *) &(Argument[i]),
                     0, (void *) &(ID[i]));
     }

     for (i = 0; i < NO_THREADS; i++) {  /* wait for all threads     */
          thr_join(ID[i], 0, (void *) &(Status[i]));
          printf("Parent found thread %d done\n", i);
     }
     printf("Parent exits ...\n");
}