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

#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/sem.h>

#include "binSem.h"

static int sem_id;


int main(int argc, char *argv[])
{
    int i;
    int pause_time;
    char op_char = 'C';
    FILE *fd;
    char name[]="temp2.txt";

    srand((unsigned int)getpid());
    
    sem_id = start_semvalue(1234);

    if (!set_semvalue(sem_id,1)) {
         fprintf(stderr, "Failed to initialize semaphore\n");
         exit(EXIT_FAILURE);
    }
    

    if (fork() == 0){
      for(i = 0; i < 10; i++) {        

          if (!semaphore_p(sem_id)) exit(EXIT_FAILURE);

            /* start of critical section */
          fd = fopen(name, "a");
          fprintf(fd, "%c", op_char);fflush(stdout);
          pause_time = rand() % 3;
          sleep(pause_time);
          fprintf(fd, "%c", op_char);fflush(stdout);
          fclose(fd);
            /* end of critical section */        

          if (!semaphore_v(sem_id)) exit(EXIT_FAILURE);
        
          pause_time = rand() % 2;
          sleep(pause_time);
        }    

	exit(0);

    }
    /* we're in the parent's code */
    op_char = 'P';

      for(i = 0; i < 10; i++) {        

          if (!semaphore_p(sem_id)) exit(EXIT_FAILURE);

            /* start of critical section */
          fd = fopen(name, "a");
          fprintf(fd, "%c", op_char);fflush(stdout);
          pause_time = rand() % 3;
          sleep(pause_time);
          fprintf(fd, "%c", op_char);fflush(stdout);
          fclose(fd);
            /* end of critical section */        

          if (!semaphore_v(sem_id)) exit(EXIT_FAILURE);
        
          pause_time = rand() % 2;
          sleep(pause_time);
        }    
    for (i = 0; i < 2; i++)
	wait(NULL);

    printf("\n%d - finished\n", getpid());

    del_semvalue(sem_id);
        
    exit(EXIT_SUCCESS);
}