frama-c / ACSL / WP：一组基数

Question

我经常在其他正式规范中使用集合的基数，并且想知道是否可以在带有WP frama-c插件的ACSL中使用它。

例如，我觉得写起来更清晰assumes card({*a, *b, *c}) == 3而不是assumes *a != *b && *a != *c && *b != *c

Answer 1

好吧，我找到了一种解决方案（我警告您一个很慢的解决方案，仅在下面的示例中，必须将超时从10秒更改为30秒）。它还在Frama-C版本Calcium中被打破，声称它找不到Qed库（该错误似乎是在尝试调用logic boolean类型的Frama-C函数）。它可以在Frama-C版本的Chlorine中正常工作（未测试其他版本）。

/* "set" appears to be a reserved word in frama-c */

/*@ predicate full_card{L}(unsigned int* the_set, integer set_size) =
  \forall integer a, b; 0 <= a < set_size && 0 <= b < set_size && a != b ==> the_set[a] != the_set[b];
*/

/*@ logic boolean in_set_bool{L}(unsigned int* the_set, integer set_size, unsigned int element) =
  set_size == 0 ? \false : element == the_set[0] || in_set_bool(the_set + 1, set_size - 1, element);
*/

/*@ logic integer card{L}(unsigned int* the_set, integer set_size) =
  set_size == 0 ? 0 : (
    in_set_bool(the_set + 1, set_size - 1, the_set[0])
      ? card(the_set + 1, set_size - 1)
      : card(the_set + 1, set_size - 1) + 1);
*/

int main(int argc, char** argv) {
  unsigned int set[] = { 1, 2, 3 };
  unsigned int set_size = 3;

  /*@ assert full_card(&set[0], set_size); */
  /*@ assert card(&set[0], set_size) == 3; */

  unsigned int set_two[] = { 3, 2, 1, 3 };
  unsigned int set_two_size = 4;

  /*@ assert card(&set_two[0], set_two_size) == 3; */
  /*@ assert !full_card(&set_two[0], set_two_size); */
}