Added basic TCP networking for the server.

The client's networking is still very experimental and
the actual protocol is not yet specified for either side.

1 files changed, 80 insertions, 0 deletions

diff --git a/src/main/scala/Server/Client.scala b/src/main/scala/Server/Client.scala
new file mode 100644
index 0000000..c7ff075
--- /dev/null
+++ b/src/main/scala/Server/Client.scala
@@ -0,0 +1,80 @@
+package o1game.Server
+
+import java.net.Socket
+import scala.math.min
+import o1game.constants.*
+
+object Client:
+	def parseClient(data: String, socket: Socket): Client =
+		Client(socket, Some(GameCharacter(data, Vector())))
+
+class Client(val socket: Socket, val character: Option[GameCharacter]):
+	private var incompleteMessage: Array[Byte] =
+		Array.fill(MAX_MSG_SIZE)(0.toByte)
+	private var incompleteMessageIndex = 0
+
+	/** Calculates the amount of bytes available for future incoming messages
+	 */
+	def spaceAvailable: Int = MAX_MSG_SIZE - incompleteMessageIndex
+
+	/** Sets `data` as received for the client.
+	 *
+	 *  @return false means there was not enough space to receive the message
+	 */
+	def receiveData(data: Vector[Byte]): Boolean =
+		for i <- 0 until min(data.length, spaceAvailable) do
+			this.incompleteMessage(this.incompleteMessageIndex + i) = data(i)
+		this.incompleteMessageIndex += data.length
+		this.incompleteMessageIndex =
+			min(this.incompleteMessageIndex, MAX_MSG_SIZE)
+		data.length < spaceAvailable
+
+	/** Returns one line of data if there are any line breaks.
+	 *  Removes the parsed data from the message buffering area.
+	 */
+	private def nextLine(): Option[String] =
+		val nextLF = this.incompleteMessage.indexOf(LF)
+		if nextLF != -1 then
+			val message = this.incompleteMessage.take(nextLF)
+			val rest = this.incompleteMessage.drop(nextLF + 1)
+			this.incompleteMessage = rest ++ Array.fill(nextLF + 1)(0.toByte)
+			// TODO: the conversion may probably be exploited to crash the server
+			Some(String(message))
+		else
+			None
+
+	/** Causes the client to take the actions it has received
+	 */
+	def executeActions(): Unit =
+		LazyList.continually(this.nextLine())
+			.takeWhile(_.isDefined)
+			.flatten
+			.foreach(s => println(s"`$this` executing `$s`"))
+
+
+class Clients(maxClients: Int):
+	private val clients: Array[Option[Client]] = Array.fill(maxClients)(None)
+
+	/** Adds `client` to this collection of clients.
+	 *
+	 * @param client the Client to add
+	 * @return true if there was room for the client
+	 *         i.e. fewer clients than `maxClients`, false otherwise
+	 */
+	def addClient(client: Client): Boolean =
+		val i = this.clients.indexOf(None)
+		if i == -1 then
+			false
+		else
+			this.clients(i) = Some(client)
+			true
+
+	def allClients: Iterable[Client] = clients.toVector.flatten
+	def foreach(f: Client => Any): Unit = this.clients.flatten.foreach(f)
+	def removeNonSatisfying(f: Client => Boolean): Unit =
+		for i <- this.clients.indices do
+			this.clients(i) match
+				case Some(c) =>
+					if !f(c) then
+						this.clients(i) = None
+				case None =>
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