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

/*
 * 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;
        }
    }
}