public IPTool getNextSubNet(long numberOfHosts)
{
IPTool ip = IPTool.getNextIP(this.getBroadCast());
ip.setIp(this.long2String(ip.ip2Long() + (long)1));
ip.setFirstSubNetBit(this.isFirstSubNetBit());
int lastPrefix = ip.getNetworkClassPrefix();
int prefix = 30;
do
{
if (prefix < ip.getNetworkClassPrefix())
{
return(null); // no subnet found
}
ip.setNetworkPrefix(prefix);
prefix--;
// ignore subnetbit?
if (!ip.isFirstSubNetBit() && prefix == lastPrefix + 1)
{
prefix--;
}
}while (ip.getMaxNetworkHosts() < numberOfHosts);
return(ip);
}