Added Packet.readFrom(DataInputStream) and MalformedPacketException

src/main/java/org/fnet/mcrconapi/MalformedPacketException.java

@@ -0,0 +1,13 @@
+package org.fnet.mcrconapi;
+
+import java.io.IOException;
+
+public class MalformedPacketException extends IOException {
+
+	private static final long serialVersionUID = -6409356862198025733L;
+
+	public MalformedPacketException(String message) {
+		super(message);
+	}
+
+}

src/main/java/org/fnet/mcrconapi/Packet.java

@@ -21,8 +21,9 @@
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  * SOFTWARE.
  *******************************************************************************/
-package org.fnet.rcon;
+package org.fnet.mcrconapi;
 
+import java.io.DataInputStream;
 import java.io.DataOutputStream;
 import java.io.IOException;
 import java.nio.charset.Charset;
@@ -46,6 +47,31 @@ public class Packet {
 	private int type;
 	private byte[] payload;
 
+	private Packet() {
+	}
+
+	public static Packet readFrom(DataInputStream dataStream) throws IOException {
+		Packet packet = new Packet();
+		packet.length = dataStream.readInt();
+		if (packet.length < 10)
+			throw new MalformedPacketException("Packet length lower than ten (minimum package size)");
+		packet.requestID = dataStream.readInt();
+		packet.type = dataStream.readInt();
+		if (packet.type != TYPE_LOGIN && packet.type != TYPE_AUTH_RESPONSE && packet.type != TYPE_COMMAND
+				&& packet.type != TYPE_COMMAND_RESPONSE)
+			throw new MalformedPacketException("Packet type is none of allowed packet types");
+		int payloadLength = packet.length - (Integer.BYTES * 2 + Byte.BYTES * 2);
+		packet.payload = new byte[payloadLength];
+		for (int i = 0; i < payloadLength; i++) {
+			packet.payload[i] = dataStream.readByte();
+		}
+		if (dataStream.readByte() != 0)
+			throw new MalformedPacketException("Payload terminator byte not zero");
+		if (dataStream.readByte() != 0)
+			throw new MalformedPacketException("Packet terminator byte not zero");
+		return packet;
+	}
+
 	/**
 	 * Generates a new packet with a type and a payload given. The length and
 	 * requestID are automatically generated where the requestID is a value that

src/test/java/org/fnet/mcrconapi/PacketTest.java

@@ -21,15 +21,17 @@
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  * SOFTWARE.
  *******************************************************************************/
-package mcrconapi;
+package org.fnet.mcrconapi;
 
 import static org.junit.Assert.*;
 
+import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
+import java.io.DataInputStream;
 import java.io.DataOutputStream;
 import java.io.IOException;
 
-import org.fnet.rcon.Packet;
+import org.fnet.mcrconapi.Packet;
 import org.junit.Test;
 
 public class PacketTest {
@@ -42,14 +44,14 @@ public class PacketTest {
 	@Test
 	public void testGetLength() {
 		Packet packet = new Packet(0, "Test");
-		assertTrue(packet.getLength() == 14);
+		assertEquals(14, packet.getLength());
 	}
 
 	@Test
 	public void testGetLengthAfterPayloadChange() {
 		Packet packet = new Packet(0, "Test");
 		packet.setPayload("Teststring");
-		assertTrue(packet.getLength() == 20);
+		assertEquals(20, packet.getLength());
 	}
 
 	@Test
@@ -71,12 +73,75 @@ public void testWriteTo() throws IOException {
 					arrayStream.toByteArray());
 		}
 	}
-
+
+	@Test
+	public void testWriteToNoPayload() throws IOException {
+		Packet packet = new Packet(3, "");
+		// Set the request id so we don't have to get the current requestId
+		// counter value with reflections
+		packet.setRequestID(1);
+		try (ByteArrayOutputStream arrayStream = new ByteArrayOutputStream(packet.getLength());
+				DataOutputStream dataStream = new DataOutputStream(arrayStream)) {
+			packet.writeTo(dataStream);
+			assertArrayEquals(new byte[] { 0, 0, 0, 10, 0, 0, 0, 1, 0, 0, 0, 3, 0, 0 },
+					arrayStream.toByteArray());
+		}
+	}
+
 	@Test
 	public void testAsciiEncoding() {
 		Packet packet = new Packet(0, "üa");
 		assertNotEquals('ü', packet.getPayloadAsString().charAt(0));
 		assertEquals('a', packet.getPayloadAsString().charAt(1));
 	}
 
+	@Test
+	public void testReadFrom() throws IOException {
+		byte[] packetData = new byte[] { 0, 0, 0, 14, 0, 0, 0, 1, 0, 0, 0, 3, 84, 101, 115, 116, 0, 0 };
+		try (ByteArrayInputStream inputStream = new ByteArrayInputStream(packetData);
+				DataInputStream dataStream = new DataInputStream(inputStream)) {
+			Packet packet = Packet.readFrom(dataStream);
+			assertEquals(14, packet.getLength());
+			assertEquals(1, packet.getRequestID());
+			assertEquals(3, packet.getType());
+			assertEquals("Test", packet.getPayloadAsString());
+		}
+	}
+
+	@Test(expected = MalformedPacketException.class)
+	public void testReadFromThrowsExceptionOnWrongType() throws IOException {
+		byte[] packetData = new byte[] { 0, 0, 0, 14, 0, 0, 0, 1, 0, 0, 0, 4, 84, 101, 115, 116, 0, 0 };
+		try (ByteArrayInputStream inputStream = new ByteArrayInputStream(packetData);
+				DataInputStream dataStream = new DataInputStream(inputStream)) {
+			Packet.readFrom(dataStream);
+		}
+	}
+
+	@Test(expected = MalformedPacketException.class)
+	public void testReadFromThrowsExceptionIfLengthTooShort() throws IOException {
+		byte[] packetData = new byte[] { 0, 0, 0, 13, 0, 0, 0, 1, 0, 0, 0, 3, 84, 101, 115, 116, 0, 0 };
+		try (ByteArrayInputStream inputStream = new ByteArrayInputStream(packetData);
+				DataInputStream dataStream = new DataInputStream(inputStream)) {
+			Packet.readFrom(dataStream);
+		}
+	}
+
+	@Test(expected = MalformedPacketException.class)
+	public void testReadFromThrowsExceptionIfLengthTooShort2() throws IOException {
+		byte[] packetData = new byte[] { 0, 0, 0, 9, 0, 0, 0, 1, 0, 0, 0, 3, 84, 101, 115, 116, 0, 0 };
+		try (ByteArrayInputStream inputStream = new ByteArrayInputStream(packetData);
+				DataInputStream dataStream = new DataInputStream(inputStream)) {
+			Packet.readFrom(dataStream);
+		}
+	}
+
+	@Test(expected = IOException.class)
+	public void testReadFromThrowsExceptionIfLengthTooLong() throws IOException {
+		byte[] packetData = new byte[] { 0, 0, 0, 15, 0, 0, 0, 1, 0, 0, 0, 3, 84, 101, 115, 116, 0, 0 };
+		try (ByteArrayInputStream inputStream = new ByteArrayInputStream(packetData);
+				DataInputStream dataStream = new DataInputStream(inputStream)) {
+			Packet.readFrom(dataStream);
+		}
+	}
+
 }