Utility classes to handle IPv4 addresses

pandalib-util/src/main/java/fr/pandacube/lib/util/network/IPv4Address.java

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+package fr.pandacube.lib.util.network;
+
+import java.net.Inet4Address;
+
+/**
+ * Represents an IPv4 address.
+ */
+public class IPv4Address {
+
+
+    private final int address;
+
+    /**
+     * Creates an IPv4 from the binary content of the provided integer.
+     * @param address the integer used for the 32 bits of the address.
+     */
+    public IPv4Address(int address) {
+        this.address = address;
+    }
+
+
+    /**
+     * Creates an IPv4 from the binary content of the provided bytes.
+     * @param address the 4 bytes used for the address. The byte at index 0 contains the most significant bits of the
+     *                address.
+     */
+    public IPv4Address(byte[] address) {
+        this((checkIPv4ByteArray(address)[0] << 24)
+                | (address[1] << 16)
+                | (address[2] << 8)
+                |  address[3]);
+    }
+
+
+    /**
+     * Creates an IPv4 from the 4 provided integers.
+     * @param b0 the most significant byte of the address.
+     *           Only the 8 least significant bits of this integer will be used.
+     * @param b1 the second most significant byte of the address.
+     *           Only the 8 least significant bits of this integer will be used.
+     * @param b2 the third most significant byte of the address.
+     *           Only the 8 least significant bits of this integer will be used.
+     * @param b3 the least significant byte of the address.
+     *           Only the 8 least significant bits of this integer will be used.
+     */
+    public IPv4Address(int b0, int b1, int b2, int b3) {
+        this(((b0 & 0xFF) << 24)
+           | ((b1 & 0xFF) << 16)
+           | ((b2 & 0xFF) << 8)
+           | ((b3 & 0xFF)));
+    }
+
+
+    /**
+     * Creates an IPv4 from the provided {@link java.net.Inet4Address}.
+     * @param address the {@link java.net.Inet4Address}.
+     */
+    public IPv4Address(Inet4Address address) {
+        this(address.getAddress());
+    }
+
+
+    private static byte[] checkIPv4ByteArray(byte[] address) {
+        if (address == null || address.length != 4)
+            throw new IllegalArgumentException("address must not be null and be of length 4.");
+        return address;
+    }
+
+
+    /**
+     * Gets the bytes of this IPv4 address.
+     * <p>
+     * The byte at index 0 contains the most significant bits of the address.
+     * @return the bytes of this IPv4 address.
+     */
+    public byte[] getByteArray() {
+        return new byte[] {
+                (byte) (address >> 24 & 0xFF),
+                (byte) (address >> 16 & 0xFF),
+                (byte) (address >>  8 & 0xFF),
+                (byte) (address       & 0xFF)
+        };
+    }
+
+
+    /**
+     * Gets the bytes of this IPv4 address represented as integers.
+     * <p>
+     * The byte at index 0 contains the most significant bits of the address.
+     * @return the bytes of this IPv4 address represented as integers.
+     */
+    public int[] getIntArray() {
+        return new int[] {
+                address >> 24 & 0xFF,
+                address >> 16 & 0xFF,
+                address >>  8 & 0xFF,
+                address       & 0xFF
+        };
+    }
+
+    /**
+     * Creates a new IPv4 address with only the network bits sets according to this IPv4 address.
+     * @param networkBits the bits count of the network part of the returned address. Must be between 0 and 32 inclusive.
+     * @return a new IPv4 address.
+     */
+    public IPv4Address asNetworkAddress(int networkBits) {
+        if (networkBits < 0 || networkBits > 32)
+            throw new IllegalArgumentException("invalid network bits count: " + networkBits);
+        int shift = 32 - networkBits;
+        return new IPv4Address(address >> shift << shift);
+    }
+
+    /**
+     * Creates a new IPv4 address with only the host bits sets according to this IPv4 address.
+     * @param networkBits the bits count of the network part of the returned address. Must be between 0 and 32 inclusive.
+     * @return a new IPv4 address.
+     */
+    public IPv4Address asHostAddress(int networkBits) {
+        if (networkBits < 0 || networkBits > 32)
+            throw new IllegalArgumentException("invalid network bits count: " + networkBits);
+        return new IPv4Address(address << networkBits >> networkBits);
+    }
+
+
+    @Override
+    public String toString() {
+        int[] Parts = getIntArray();
+        return Parts[0] + "." + Parts[1] + "." + Parts[2] + "." + Parts[3];
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        return o == this || (o instanceof IPv4Address other && address == other.address);
+    }
+
+    @Override
+    public int hashCode() {
+        return address;
+    }
+}

pandalib-util/src/main/java/fr/pandacube/lib/util/network/IPv4Network.java

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+package fr.pandacube.lib.util.network;
+
+/**
+ * Represents an IPv4 network address (an IP address and a network mask).
+ */
+public class IPv4Network {
+
+    private final IPv4Address networkAddress;
+    private final int bits;
+
+    /**
+     * Creates a new IPv4 network address.
+     * @param networkAddress the address.
+     * @param bits the bits count of the network part of the address. Must be between 0 and 32 inclusive.
+     */
+    private IPv4Network(IPv4Address networkAddress, int bits) {
+        if (networkAddress == null)
+            throw new IllegalArgumentException("networkAddress cannot be null.");
+        if (bits < 0 || bits > 32)
+            throw new IllegalArgumentException("invalid network bits count: " + bits);
+        this.networkAddress = networkAddress.asNetworkAddress(bits);
+        this.bits = bits;
+    }
+
+
+    /**
+     * Telles if the provided {@link IPv4Address} is part of this network.
+     * @param address the provided IPv4 address.
+     * @return true if the provided {@link IPv4Address} is part of this network, false otherwise.
+     */
+    public boolean isInNetwork(IPv4Address address) {
+        return address.asNetworkAddress(bits).equals(networkAddress);
+    }
+}