initial commit

crychat/client/Main.java

@@ -0,0 +1,26 @@
+package client;
+
+import client.log.EventLogger;
+import client.net.Client;
+
+import java.io.BufferedReader;
+import java.io.InputStreamReader;
+
+public class Main {
+
+    public static EventLogger console;
+
+    public static void main(String[] args) {
+        System.out.println("Client!");
+        console = new EventLogger(System.out);
+        Client c = new Client("localhost", 5001);
+        BufferedReader r = new BufferedReader(new InputStreamReader(System.in));
+        while (true) {
+            try {
+                c.write(r.readLine().getBytes());
+            } catch (Throwable e) {
+                e.printStackTrace();
+            }
+        }
+    }
+}

crychat/client/log/EventLogger.java

@@ -0,0 +1,37 @@
+package client.log;
+
+import java.io.PrintStream;
+
+public class EventLogger {
+
+    private static final String ANSI_RESET = "\u001B[0m";
+    private static final String ANSI_RED = "\u001B[31m";
+    private static final String ANSI_GREEN = "\u001B[32m";
+    private static final String ANSI_BLUE = "\u001B[34m";
+    private static final String ANSI_WHITE = "\u001B[37m";
+    private final PrintStream stream;
+
+    public EventLogger(PrintStream stream) {
+        this.stream = stream;
+    }
+
+    public void println(String msg) {
+        stream.println(msg);
+    }
+
+    public void error(String msg) {
+        stream.println(ANSI_WHITE + "[" + ANSI_RED + "-" + ANSI_WHITE + "] " + msg + ANSI_RESET);
+    }
+
+    public void info(String msg) {
+        stream.println(ANSI_WHITE + "[" + ANSI_BLUE + "*" + ANSI_WHITE + "] " + msg + ANSI_RESET);
+    }
+
+    public void success(String msg) {
+        stream.println(ANSI_WHITE + "[" + ANSI_GREEN + "+" + ANSI_WHITE + "] " + msg + ANSI_RESET);
+    }
+
+    public void close() {
+        stream.close();
+    }
+}

crychat/client/net/Client.java

@@ -0,0 +1,54 @@
+package client.net;
+
+import client.Main;
+import client.util.CeasarChipher;
+
+import java.io.DataInputStream;
+import java.io.DataOutputStream;
+import java.io.IOException;
+import java.net.Socket;
+
+public class Client {
+
+    private Socket s;
+    private DataInputStream inputStream;
+    private DataOutputStream outputStream;
+    private Thread t;
+
+    public Client(String host, int port) {
+        try {
+            s = new Socket(host, port);
+            inputStream = new DataInputStream(s.getInputStream());
+            outputStream = new DataOutputStream(s.getOutputStream());
+            t = new Thread(() -> {
+                try {
+                    while (true) {
+                        int len = inputStream.readInt();
+                        byte[] buf = new byte[len];
+                        inputStream.readFully(buf, 0, len);
+
+                        //TEST
+                        System.out.println(new String(CeasarChipher.decrypt(buf)));
+                    }
+                } catch (IOException e) {
+                    Main.console.error("An error occurred while reading");
+                    e.printStackTrace();
+                }
+            });
+            t.start();
+        } catch (Throwable e) {
+            Main.console.error("An error occurred while creating client!");
+            e.printStackTrace();
+        }
+    }
+
+    public void write(byte[] buf) {
+        try {
+            outputStream.writeInt(buf.length);
+            outputStream.write(CeasarChipher.encrypt(buf));
+        } catch (Throwable e) {
+            server.Main.console.error("An error occurred while writing data!");
+            e.printStackTrace();
+        }
+    }
+}

crychat/client/util/CeasarChipher.java

@@ -0,0 +1,18 @@
+package client.util;
+
+public class CeasarChipher {
+
+    public static byte[] encrypt(byte[] x) {
+        for (int i = 0; i < x.length; ++i) {
+            x[i] = (byte) ((x[i] + 3) % 256);
+        }
+        return x;
+    }
+
+    public static byte[] decrypt(byte[] x) {
+        for (int i = 0; i < x.length; ++i) {
+            x[i] = (byte) ((x[i] + 253) % 256);
+        }
+        return x;
+    }
+}

crychat/server/Main.java

@@ -0,0 +1,26 @@
+package server;
+
+import server.log.EventLogger;
+import server.net.ChatServer;
+import server.util.ServerBuilder;
+
+public class Main {
+
+    public static EventLogger console;
+
+    public static void main(String[] args) {
+        console = new EventLogger(System.out);
+        ChatServer server = ServerBuilder.buildServerFromConsoleArgs(args);
+
+        if (server == null) {
+            console.info("Didn't initialize ChatServer!");
+            console.close();
+            return;
+        }
+
+        //Start the Server
+        server.start();
+
+        //console.close();
+    }
+}

crychat/server/log/EventLogger.java

@@ -0,0 +1,37 @@
+package server.log;
+
+import java.io.PrintStream;
+
+public class EventLogger {
+
+    private static final String ANSI_RESET = "\u001B[0m";
+    private static final String ANSI_RED = "\u001B[31m";
+    private static final String ANSI_GREEN = "\u001B[32m";
+    private static final String ANSI_BLUE = "\u001B[34m";
+    private static final String ANSI_WHITE = "\u001B[37m";
+    private final PrintStream stream;
+
+    public EventLogger(PrintStream stream) {
+        this.stream = stream;
+    }
+
+    public void println(String msg) {
+        stream.println(msg);
+    }
+
+    public void error(String msg) {
+        stream.println(ANSI_WHITE + "[" + ANSI_RED + "-" + ANSI_WHITE + "] " + msg + ANSI_RESET);
+    }
+
+    public void info(String msg) {
+        stream.println(ANSI_WHITE + "[" + ANSI_BLUE + "*" + ANSI_WHITE + "] " + msg + ANSI_RESET);
+    }
+
+    public void success(String msg) {
+        stream.println(ANSI_WHITE + "[" + ANSI_GREEN + "+" + ANSI_WHITE + "] " + msg + ANSI_RESET);
+    }
+
+    public void close() {
+        stream.close();
+    }
+}

crychat/server/net/ChatClient.java

@@ -0,0 +1,68 @@
+package server.net;
+
+import server.Main;
+import server.util.CeasarChipher;
+
+import java.io.DataInputStream;
+import java.io.DataOutputStream;
+import java.io.IOException;
+import java.net.Socket;
+
+public class ChatClient {
+
+    private final int id;
+    private final Socket s;
+    private final DataInputStream inputStream;
+    private final DataOutputStream outputStream;
+    private final Thread t;
+
+    public ChatClient(int id, Socket s, DataInputStream inputStream, DataOutputStream outputStream) {
+        this.id = id;
+        this.s = s;
+        this.inputStream = inputStream;
+        this.outputStream = outputStream;
+        t = new Thread(() -> {
+            try {
+                while (true) {
+                    int len = inputStream.readInt();
+                    byte[] buf = new byte[len];
+                    inputStream.readFully(buf, 0, len);
+
+                    //TEST
+                    System.out.println(new String(CeasarChipher.decrypt(buf)));
+                }
+            } catch (IOException e) {
+                Main.console.error("An error occurred while reading from client (" + s.getRemoteSocketAddress().toString() + ") [id: " + id + "]");
+                e.printStackTrace();
+            }
+        });
+        try {
+            t.start();
+        } catch (Throwable e) {
+            Main.console.error("An error occurred while starting client (" + s.getRemoteSocketAddress().toString() + ") [id: " + id + "]");
+            e.printStackTrace();
+        }
+    }
+
+    public void write(byte[] buf) {
+        try {
+            outputStream.writeInt(buf.length);
+            outputStream.write(CeasarChipher.encrypt(buf));
+        } catch (Throwable e) {
+            Main.console.error("An error occurred while writing data to client (" + s.getRemoteSocketAddress().toString() + ") [id: " + id + "]");
+            e.printStackTrace();
+        }
+    }
+
+    public void disconnect() {
+        try {
+            t.stop();
+            s.close();
+            inputStream.close();
+            outputStream.close();
+        } catch (Throwable e) {
+            Main.console.error("An error occurred while disconnecting client (" + s.getRemoteSocketAddress().toString() + ") [id: " + id + "]");
+            e.printStackTrace();
+        }
+    }
+}

crychat/server/net/ChatServer.java

@@ -0,0 +1,61 @@
+package server.net;
+
+import server.Main;
+import server.util.Queue;
+
+import java.io.DataInputStream;
+import java.io.DataOutputStream;
+import java.io.IOException;
+import java.net.ServerSocket;
+import java.net.Socket;
+
+public class ChatServer {
+
+    private final int port;
+    private volatile int n_users;
+    private final Thread t;
+    private ServerSocket server;
+    private Queue<Integer> id_q;
+
+    public ChatServer(int port, int max_users) {
+        Main.console.info("Initializing server on port: " + port + " with max_users: " + max_users);
+        this.port = port;
+        n_users = 0;
+        t = new Thread(() -> {
+            try {
+                while (true) {
+                    if (n_users == max_users) continue;
+                    Socket s = server.accept();
+                    DataInputStream inputStream = new DataInputStream(s.getInputStream());
+                    DataOutputStream outputStream = new DataOutputStream(s.getOutputStream());
+                    ChatClient client = new ChatClient(id_q.deq(), s, inputStream, outputStream);
+                    n_users++;
+                }
+            } catch (IOException e) {
+                Main.console.error("An error occurred while listening for connections!");
+                e.printStackTrace();
+            }
+        });
+        id_q = new Queue<>(max_users);
+        for (int i = 0; i < max_users; ++i) id_q.enq(i);
+    }
+
+    public void start() {
+        try {
+            server = new ServerSocket(port);
+            t.start();
+        } catch (Throwable e) {
+            Main.console.error("An error occurred while starting the ChatServer!");
+            e.printStackTrace();
+        }
+    }
+
+    public void stop() {
+        try {
+            t.stop();
+        } catch (Throwable e) {
+            Main.console.error("An error occurred while stopping the ChatServer!");
+            e.printStackTrace();
+        }
+    }
+}

crychat/server/util/CeasarChipher.java

@@ -0,0 +1,18 @@
+package server.util;
+
+public class CeasarChipher {
+
+    public static byte[] encrypt(byte[] x) {
+        for (int i = 0; i < x.length; ++i) {
+            x[i] = (byte) ((x[i] + 3) % 256);
+        }
+        return x;
+    }
+
+    public static byte[] decrypt(byte[] x) {
+        for (int i = 0; i < x.length; ++i) {
+            x[i] = (byte) ((x[i] + 253) % 256);
+        }
+        return x;
+    }
+}

crychat/server/util/Queue.java

@@ -0,0 +1,35 @@
+package server.util;
+
+/*
+    !!! WORK IN PROGRESS !!!
+
+    trying to implement a wait-free queue
+ */
+
+import java.util.concurrent.atomic.AtomicReferenceArray;
+
+public class Queue<T> {
+
+    private volatile int head = 0, tail = 0;
+    private final int capacity;
+    private AtomicReferenceArray<T> items;
+
+    public Queue(int capacity) {
+        this.capacity = capacity;
+        items = new AtomicReferenceArray<>(capacity);
+    }
+
+    public boolean enq(T x) {
+        if (tail - head == capacity) return false;
+        items.set((tail + 1) % capacity, x);
+        tail++;
+        return true;
+    }
+
+    public T deq() {
+        if (tail - head == 0) return null;
+        T x = items.get((head + 1) % capacity);
+        head++;
+        return x;
+    }
+}

crychat/server/util/ServerBuilder.java

@@ -0,0 +1,67 @@
+package server.util;
+
+import server.Main;
+import server.net.ChatServer;
+
+public class ServerBuilder {
+
+    private static final int DEFAULT_PORT = 5000;
+    private static final int MAX_USERS = 5;
+    private static final String HELP_MSG = """
+            -h, -help:              prints this help message.
+            -p, -port:              sets the port for the ChatServer
+            """;
+
+    public static ChatServer buildServerFromConsoleArgs(String[] args) {
+        int port = DEFAULT_PORT;
+        int max_users = MAX_USERS;
+        int ptr = 0;
+        while (ptr < args.length) {
+            switch (args[ptr]) {
+                case "-h":
+                case "-help":
+                    if (ptr != 0 || args.length > 1) {
+                        Main.console.error("You cannot use -h or -help in combination with other commands!");
+                        return null;
+                    }
+                    Main.console.println(HELP_MSG);
+                    return null;
+                case "-p":
+                case "-port":
+                    try {
+                        if (++ptr == args.length) {
+                            Main.console.error("Please enter a port-number (0 to 65536)!");
+                            return null;
+                        }
+                        port = Integer.parseInt(args[ptr], 10);
+                        if (port < 0 || port >= 65536) {
+                            Main.console.error("Please enter a valid port-number (0 to 65536)!");
+                            return null;
+                        }
+                    } catch (NumberFormatException e) {
+                        Main.console.error("Please enter a valid port-number (0 to 65536)!");
+                        return null;
+                    }
+                    break;
+                case "-m":
+                case "-max_users":
+                    try {
+                        if (++ptr == args.length) {
+                            Main.console.error("Please enter a user count!");
+                            return null;
+                        }
+                        max_users = Integer.parseInt(args[ptr], 10);
+                    } catch (NumberFormatException e) {
+                        Main.console.error("Please enter a valid user count!");
+                        return null;
+                    }
+                    break;
+                default:
+                    Main.console.error("Couldn't parse argument: '" + args[ptr] + "', please try '-h' or '-help' for help.");
+                    return null;
+            }
+            ++ptr;
+        }
+        return new ChatServer(port, max_users);
+    }
+}