void setBit(int bit, u_char *data) {
    u_char * seg = data + (bit / 8);
    *seg |= 1 << (bit % 8);
}

int getBit(int bit, u_char *data) {
    u_char * seg = data + (bit / 8);
    return !!(*seg & (1 << (bit % 8)));
}