/* Utility functions. */

/* Comparison function for pointers to |int|s.
   |param| is not used. */
int
compare_ints (const void *pa, const void *pb, void *param)
{
  const int *a = pa;
  const int *b = pb;

  if (*a < *b)
    return -1;
  else if (*a > *b)
    return +1;
  else
    return 0;
}

/* Prints |message| on |stderr|, which is formatted as for |printf()|,
   and terminates the program unsuccessfully. */
static void
fail (const char *message, ...)
{
  va_list args;

  fprintf (stderr, "%s: ", pgm_name);

  va_start (args, message);
  vfprintf (stderr, message, args);
  va_end (args);

  putchar ('\n');

  exit (EXIT_FAILURE);
}

/* Allocates and returns a pointer to |size| bytes of memory.
   Aborts if allocation fails. */
static void *
xmalloc (size_t size)
{
  void *block = malloc (size);
  if (block == NULL && size != 0)
    fail ("out of memory");
  return block;
}