#include <signal.h>
#include <setjmp.h>
#include "dllist.h"


int TIME = 0;
jmp_buf Env;

void alarm_handler(int dummy)
{
  TIME++;
  alarm(1);
  signal(SIGALRM, alarm_handler);
  longjmp(Env, TIME);
}

enumerate_primes1(int *current_test, int *largest_prime)
{
  int i;
  char s[1000];

  while(1) {
    for(i = 2; i*i < *current_test && *current_test % i != 0; i++) ;
    /* we could emit the prime number here */
    if (*current_test % i != 0) {
       *largest_prime = *current_test;
    }
    *current_test = *current_test + 1;
  }
}
    
enumerate_primes2(int *current_test, int *largest_prime, Dllist d)
{
  Dllist tmp;
  int i;
  char s[1000];
  int prime;
 

  while(1) {
    prime = 1;
    for (tmp = dll_first(d); prime && (tmp != d) && 
                         (tmp->val.i) * (tmp->val.i) < *current_test; 
         tmp = dll_next(tmp)) {
      if (*current_test % (tmp->val.i) == 0) {
        prime = 0;
      }
    }
    if (prime) {
      dll_append(d, new_jval_i(*current_test));
      *largest_prime = *current_test;
    }
    *current_test = *current_test + 1;
  }
}
  
main()
{
  int test1, largest_prime1;
  int test2, largest_prime2;
  Dllist d;
  int i;

  test1 = 2;
  test2 = 2;
  largest_prime1 = 2;
  largest_prime2 = 2;
  
  d = new_dllist();

  signal(SIGALRM, alarm_handler);
  alarm(1);

  i = setjmp(Env);
  printf("%4d   EP1: %10d        EP2: %10d\n", i, 
            largest_prime1, largest_prime2);
  if (i % 2 == 0) {
    enumerate_primes1(&test1, &largest_prime1);
  } else {
    enumerate_primes2(&test2, &largest_prime2, d);
  }

}