int zuiCompareByCardinality(const void *s1, const void *s2) {
    unsigned long first = zuiLength((zsetopsrc*)s1);
    unsigned long second = zuiLength((zsetopsrc*)s2);
    if (first > second) return 1;
    if (first < second) return -1;
    return 0;
}
int zuiCompareByCardinality(const void *s1, const void *s2) {
    unsigned long first = zuiLength((zsetopsrc*)s1);
    unsigned long second = zuiLength((zsetopsrc*)s2);
    if (first > second) return 1;
    if (first < second) return -1;
    return 0;
}