ttetwasd

crychat/client/Main.java

@@ -13,7 +13,7 @@ public class Main {
     public static void main(String[] args) {
         System.out.println("Client!");
         console = new EventLogger(System.out);
-        Client c = new Client("localhost", 5001);
+        Client c = new Client("localhost", 5000);
         BufferedReader r = new BufferedReader(new InputStreamReader(System.in));
         while (true) {
             try {

crychat/server/net/ChatServer.java

@@ -21,6 +21,8 @@ public class ChatServer {
         Main.console.info("Initializing server on port: " + port + " with max_users: " + max_users);
         this.port = port;
         n_users = 0;
+        id_q = new Queue<>(max_users);
+        for (int i = 0; i < max_users; ++i) id_q.enq(i);
         t = new Thread(() -> {
             try {
                 while (true) {
@@ -37,8 +39,6 @@ public class ChatServer {
                 e.printStackTrace();
             }
         });
-        id_q = new Queue<>(max_users);
-        for (int i = 0; i < max_users; ++i) id_q.enq(i);
     }
 
     public void start() {

crychat/server/util/Queue.java

@@ -6,30 +6,53 @@ package server.util;
     trying to implement a wait-free queue
  */
 
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.atomic.AtomicMarkableReference;
 import java.util.concurrent.atomic.AtomicReferenceArray;
 
 public class Queue<T> {
 
-    private volatile int head = 0, tail = 0;
+    private AtomicMarkableReference<Integer> head, tail;
     private final int capacity;
     private AtomicReferenceArray<T> items;
 
     public Queue(int capacity) {
         this.capacity = capacity;
-        items = new AtomicReferenceArray<>(capacity);
+        this.head = new AtomicMarkableReference(0, false);
+        this.tail = new AtomicMarkableReference(0, false);
+        items = new AtomicReferenceArray<T>(capacity);
     }
 
     public boolean enq(T x) {
-        if (tail - head == capacity) return false;
-        items.set((tail + 1) % capacity, x);
-        tail++;
+        boolean[] mark = new boolean[1];
+        if (tail.get(mark) - head.get(mark) == capacity) return false;
+        int tmp;
+        do {
+            tmp = tail.get(mark);
+            System.out.println("enq: " + x);
+            System.out.println("val tmp: " + tmp);
+            System.out.println("val tmp: " + next(tmp));
+            items.compareAndSet(tmp, null, x);
+        } while (tail.compareAndSet(tmp, next(tmp), true, false));
+        System.out.println("head: " + head.getReference() + "\ntail: " + tail.getReference() + "\ndiff: " + (tail.getReference() - head.getReference()));
         return true;
     }
 
     public T deq() {
-        if (tail - head == 0) return null;
-        T x = items.get((head + 1) % capacity);
-        head++;
+        boolean[] mark = new boolean[1];
+        System.out.println("test: " + (tail.get(mark) - head.get(mark)) + "\ncap: " + capacity);
+        if (tail.get(mark) - head.get(mark) == 0) return null;
+        int tmp;
+        T x;
+        do {
+            tmp = head.get(mark);
+            System.out.println("head: " + next(tmp));
+            x = items.getAndSet(tmp, null);
+        } while (head.compareAndSet(tmp, next(tmp), false, true));
         return x;
     }
+
+    private int next(int x) {
+        return (x + 1) % capacity;
+    }
 }