问在iPhone上使用负值数据？

EN

+ (NSArray *)getDataCounters {

    BOOL   success;
    struct ifaddrs *addrs;
    const struct ifaddrs *cursor;
    const struct if_data *networkStatisc;

    int WiFiSent = 0;
    int WiFiReceived = 0;
    int WWANSent = 0;
    int WWANReceived = 0;

    NSString *name = [[NSString alloc]init];

    // getifmaddrs
    success = getifaddrs(&addrs) == 0;
    if (success)
    {
        cursor = addrs;
        while (cursor != NULL)
    {
        name = [NSString stringWithFormat:@"%s",cursor->ifa_name];
        // names of interfaces: en0 is WiFi ,pdp_ip0 is WWAN

        if (cursor->ifa_addr->sa_family == AF_LINK)
        {
            if ([name hasPrefix:@"en"])
            {
                networkStatisc = (const struct if_data *) cursor->ifa_data;
                WiFiSent += networkStatisc->ifi_obytes;
                WiFiReceived += networkStatisc->ifi_ibytes;
            }

            if ([name hasPrefix:@"pdp_ip"])
            {
                networkStatisc = (const struct if_data *) cursor->ifa_data;
                WWANSent += networkStatisc->ifi_obytes;
                WWANReceived += networkStatisc->ifi_ibytes;
            }
        }

        cursor = cursor->ifa_next;
      }

        freeifaddrs(addrs);
    }

    return [NSArray arrayWithObjects:[NSNumber numberWithInt:WiFiSent], [NSNumber numberWithInt:WiFiReceived],[NSNumber numberWithInt:WWANSent],[NSNumber numberWithInt:WWANReceived], nil];
}