public static InetAddress getAddressFromLong(Long addr) {
if (addr == null) {
return null;
}
AuAssert.check(addr >= 0 && addr < (1L << 32));
byte[] bytes =
new byte[] {
(byte) ((addr >> 24) & 0xff),
(byte) ((addr >> 16) & 0xff),
(byte) ((addr >> 8) & 0xff),
(byte) (addr & 0xff)
};
try {
return InetAddress.getByAddress(bytes);
} catch (UnknownHostException e) {
AuAssert.unreachable();
return null;
}
}
public static Long getAddressAsLong(InetAddress addr) {
if (addr == null) {
return null;
}
byte[] bytes = addr.getAddress();
AuAssert.check(bytes.length == 4); // ipv4 only
// byte & 0xff is a hack to use java unsigned byte
return ((bytes[0] & 0xffL) << 24)
+ ((bytes[1] & 0xffL) << 16)
+ ((bytes[2] & 0xffL) << 8)
+ (bytes[3] & 0xffL);
}
/**
* Get the number of network prefix bits from a netmask. This function does not validate whether
* the netmask is really usufull or not, for example, it will treat "255.255.255.255",
* "255.255.255.254", "255.255.255.252" as valid netmasks though they can not be used practically.
*
* @param netmask netmask
* @return a 1 - 32 integer indicates the network part length, -1 when the input is not a valid
* netmask.
*/
public static int getNetworkPrefixBits(long netmask) {
AuAssert.check(netmask >= 0 && netmask < (1L << 32));
int i = 0;
long tmp = netmask;
while (i <= 32) {
if ((tmp & 1L) == 1L) {
long expected = ((1L << 32) - 1L) >> i;
if ((expected & tmp) == expected) {
return 32 - i;
} else {
return -1;
}
}
++i;
tmp = tmp >> 1;
}
return -1;
}
