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source/decompiled/de/maxhenkel/voicechat/net/PacketRateLimiter.java

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+/*
+ * Decompiled with CFR 0.152.
+ * 
+ * Could not load the following classes:
+ *  org.bukkit.entity.Player
+ */
+package de.maxhenkel.voicechat.net;
+
+import java.util.UUID;
+import java.util.concurrent.ConcurrentHashMap;
+import org.bukkit.entity.Player;
+
+public class PacketRateLimiter {
+    private final ConcurrentHashMap<UUID, RateLimiter> rateLimiters = new ConcurrentHashMap();
+    private final int maxPacketsPerSecond;
+    private final int timeWindowSeconds = 5;
+
+    public PacketRateLimiter(int maxPacketsPerSecond) {
+        this.maxPacketsPerSecond = maxPacketsPerSecond;
+    }
+
+    public boolean allow(UUID player) {
+        if (this.maxPacketsPerSecond <= 0) {
+            return true;
+        }
+        RateLimiter limiter = this.rateLimiters.computeIfAbsent(player, id -> new RateLimiter(this.maxPacketsPerSecond * 5, 5000L));
+        return limiter.tryAcquire();
+    }
+
+    public void onPlayerLoggedOut(Player player) {
+        this.rateLimiters.remove(player.getUniqueId());
+    }
+
+    private static class RateLimiter {
+        private final int threshold;
+        private final long timePerTokenNanos;
+        private long lastLeakNanos;
+        private long amount;
+
+        public RateLimiter(int threshold, long windowMillis) {
+            this.threshold = threshold;
+            this.timePerTokenNanos = windowMillis * 1000000L / (long)threshold;
+            this.lastLeakNanos = System.nanoTime();
+            this.amount = 0L;
+        }
+
+        public boolean tryAcquire() {
+            long currentTime = System.nanoTime();
+            long elapsed = currentTime - this.lastLeakNanos;
+            long leakedTokens = elapsed / this.timePerTokenNanos;
+            if (leakedTokens > 0L) {
+                this.amount -= leakedTokens;
+                if (this.amount < 0L) {
+                    this.amount = 0L;
+                }
+                this.lastLeakNanos += leakedTokens * this.timePerTokenNanos;
+            }
+            if (this.amount >= (long)this.threshold) {
+                return false;
+            }
+            ++this.amount;
+            return true;
+        }
+    }
+}
+