Use FastUtil collections where possible

src/main/java/ac/grim/grimac/checks/impl/combat/Reach.java

@@ -34,6 +34,8 @@
 import com.github.retrooper.packetevents.util.Vector3d;
 import com.github.retrooper.packetevents.wrapper.play.client.WrapperPlayClientInteractEntity;
 import com.github.retrooper.packetevents.wrapper.play.client.WrapperPlayClientPlayerFlying;
+import it.unimi.dsi.fastutil.ints.Int2ObjectMap;
+import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
 import org.bukkit.util.Vector;
 
 import java.util.*;
@@ -43,7 +45,7 @@
 public class Reach extends Check implements PacketCheck {
     // Only one flag per reach attack, per entity, per tick.
     // We store position because lastX isn't reliable on teleports.
-    private final Map<Integer, Vector3d> playerAttackQueue = new HashMap<>();
+    private final Int2ObjectMap<Vector3d> playerAttackQueue = new Int2ObjectOpenHashMap<>();
     private static final List<EntityType> blacklisted = Arrays.asList(
             EntityTypes.BOAT,
             EntityTypes.CHEST_BOAT,
@@ -142,8 +144,8 @@ private boolean isKnownInvalid(PacketEntity reachEntity) {
     }
 
     private void tickBetterReachCheckWithAngle() {
-        for (Map.Entry<Integer, Vector3d> attack : playerAttackQueue.entrySet()) {
-            PacketEntity reachEntity = player.compensatedEntities.entityMap.get(attack.getKey().intValue());
+        for (Int2ObjectMap.Entry<Vector3d> attack : playerAttackQueue.int2ObjectEntrySet()) {
+            PacketEntity reachEntity = player.compensatedEntities.entityMap.get(attack.getIntKey());
             if (reachEntity != null) {
                 String result = checkReach(reachEntity, attack.getValue(), false);
                 if (result != null) {

src/main/java/ac/grim/grimac/manager/PunishmentManager.java

@@ -11,6 +11,7 @@
 import ac.grim.grimac.utils.anticheat.LogUtil;
 import ac.grim.grimac.utils.anticheat.MessageUtil;
 import io.github.retrooper.packetevents.util.folia.FoliaScheduler;
+import it.unimi.dsi.fastutil.longs.Long2ObjectOpenHashMap;
 import lombok.Getter;
 import lombok.Setter;
 import org.bukkit.Bukkit;
@@ -183,7 +184,7 @@ public void handleViolation(Check check) {
 
                 group.violations.put(currentTime, check);
                 // Remove violations older than the defined time in the config
-                group.violations.entrySet().removeIf(time -> currentTime - time.getKey() > group.removeViolationsAfter);
+                group.violations.long2ObjectEntrySet().removeIf(time -> currentTime - time.getLongKey() > group.removeViolationsAfter);
             }
         }
     }
@@ -195,7 +196,7 @@ class PunishGroup {
     @Getter
     List<ParsedCommand> commands;
     @Getter
-    HashMap<Long, Check> violations = new HashMap<>();
+    Long2ObjectOpenHashMap<Check> violations = new Long2ObjectOpenHashMap<>();
     @Getter
     int removeViolationsAfter;
 

src/main/java/ac/grim/grimac/manager/init/start/SuperDebug.java

@@ -12,6 +12,8 @@
 import ac.grim.grimac.utils.math.GrimMath;
 import com.github.retrooper.packetevents.PacketEvents;
 import com.github.retrooper.packetevents.protocol.world.states.WrappedBlockState;
+import it.unimi.dsi.fastutil.objects.Object2IntMap;
+import it.unimi.dsi.fastutil.objects.Object2IntOpenHashMap;
 import lombok.AllArgsConstructor;
 import org.bukkit.util.Vector;
 
@@ -20,7 +22,7 @@
 public final class SuperDebug extends Check implements PostPredictionCheck {
     private static final StringBuilder[] flags = new StringBuilder[256]; //  17 MB of logs in memory
 
-    Map<StringBuilder, Integer> continuedDebug = new HashMap<>();
+    Object2IntMap<StringBuilder> continuedDebug = new Object2IntOpenHashMap<>();
 
     List<VectorData> predicted = new EvictingQueue<>(60);
     List<Vector> actually = new EvictingQueue<>(60);
@@ -45,7 +47,7 @@ public void onPredictionComplete(final PredictionComplete predictionComplete) {
 
         Location location = new Location(player.x, player.y, player.z, player.xRot, player.yRot, player.bukkitPlayer == null ? "null" : player.bukkitPlayer.getWorld().getName());
 
-        for (Iterator<Map.Entry<StringBuilder, Integer>> it = continuedDebug.entrySet().iterator(); it.hasNext(); ) {
+        for (Iterator<Object2IntMap.Entry<StringBuilder>> it = continuedDebug.object2IntEntrySet().iterator(); it.hasNext(); ) {
             Map.Entry<StringBuilder, Integer> debug = it.next();
             appendDebug(debug.getKey(), player.predictedVelocity, player.actualMovement, location, player.startTickClientVel, player.baseTickAddition, player.baseTickWaterPushing);
             debug.setValue(debug.getValue() - 1);

src/main/java/ac/grim/grimac/predictionengine/UncertaintyHandler.java

@@ -13,6 +13,7 @@
 import com.github.retrooper.packetevents.protocol.attribute.Attributes;
 import com.github.retrooper.packetevents.protocol.entity.type.EntityTypes;
 import com.github.retrooper.packetevents.protocol.world.BlockFace;
+import it.unimi.dsi.fastutil.ints.Int2ObjectMap;
 import org.bukkit.util.Vector;
 
 import java.util.*;
@@ -338,10 +339,9 @@ private boolean regularHardCollision(SimpleCollisionBox expandedBB) {
     private boolean striderCollision(SimpleCollisionBox expandedBB) {
         // Stiders can walk on top of other striders
         if (player.compensatedEntities.getSelf().getRiding() instanceof PacketEntityStrider) {
-            for (Map.Entry<Integer, PacketEntity> entityPair : player.compensatedEntities.entityMap.int2ObjectEntrySet()) {
-                PacketEntity entity = entityPair.getValue();
-                if (entity.getType() == EntityTypes.STRIDER && entity != player.compensatedEntities.getSelf().getRiding() && !entity.hasPassenger(entityPair.getValue())
-                        && entity.getPossibleCollisionBoxes().isIntersected(expandedBB)) {
+            for (PacketEntity entity : player.compensatedEntities.entityMap.values()) {
+                if (entity.getType() == EntityTypes.STRIDER && entity != player.compensatedEntities.getSelf().getRiding()
+                        && !entity.hasPassenger(entity) && entity.getPossibleCollisionBoxes().isIntersected(expandedBB)) {
                     return true;
                 }
             }
@@ -355,9 +355,9 @@ private boolean boatCollision(SimpleCollisionBox expandedBB) {
         final PacketEntity riding = player.compensatedEntities.getSelf().getRiding();
         if (riding == null || !riding.isBoat()) return false;
 
-        for (Map.Entry<Integer, PacketEntity> entityPair : player.compensatedEntities.entityMap.int2ObjectEntrySet()) {
-            PacketEntity entity = entityPair.getValue();
-            if (entity != riding && entity.isPushable() && !riding.hasPassenger(entityPair.getValue()) && entity.getPossibleCollisionBoxes().isIntersected(expandedBB)) {
+        for (PacketEntity entity : player.compensatedEntities.entityMap.values()) {
+            if (entity != riding && entity.isPushable() && !riding.hasPassenger(entity)
+                    && entity.getPossibleCollisionBoxes().isIntersected(expandedBB)) {
                 return true;
             }
         }

src/main/java/ac/grim/grimac/utils/data/packetentity/PacketEntity.java

@@ -27,6 +27,8 @@
 import com.github.retrooper.packetevents.protocol.player.ClientVersion;
 import com.github.retrooper.packetevents.protocol.potion.PotionType;
 import com.github.retrooper.packetevents.util.Vector3d;
+import it.unimi.dsi.fastutil.objects.Object2IntMap;
+import it.unimi.dsi.fastutil.objects.Object2IntOpenHashMap;
 import lombok.Getter;
 
 import java.util.ArrayList;
@@ -54,7 +56,7 @@ public class PacketEntity extends TypedPacketEntity {
     private ReachInterpolationData oldPacketLocation;
     private ReachInterpolationData newPacketLocation;
 
-    private Map<PotionType, Integer> potionsMap = null;
+    private Object2IntMap<PotionType> potionsMap = null;
     protected final Map<Attribute, ValuedAttribute> attributeMap = new IdentityHashMap<>();
 
     public PacketEntity(GrimPlayer player, EntityType type) {
@@ -202,8 +204,8 @@ public PacketEntity getRiding() {
     }
 
     public OptionalInt getPotionEffectLevel(PotionType effect) {
-        final Integer amplifier = potionsMap == null ? null : potionsMap.get(effect);
-        return amplifier == null ? OptionalInt.empty() : OptionalInt.of(amplifier);
+        final int amplifier = potionsMap == null ? -1 : potionsMap.getInt(effect);
+        return amplifier == -1 ? OptionalInt.empty() : OptionalInt.of(amplifier);
     }
 
     public boolean hasPotionEffect(PotionType effect) {
@@ -212,13 +214,14 @@ public boolean hasPotionEffect(PotionType effect) {
 
     public void addPotionEffect(PotionType effect, int amplifier) {
         if (potionsMap == null) {
-            potionsMap = new HashMap<>();
+            potionsMap = new Object2IntOpenHashMap<>();
+            potionsMap.defaultReturnValue(-1);
         }
         potionsMap.put(effect, amplifier);
     }
 
     public void removePotionEffect(PotionType effect) {
         if (potionsMap == null) return;
-        potionsMap.remove(effect);
+        potionsMap.removeInt(effect);
     }
 }

src/main/java/ac/grim/grimac/utils/latency/CompensatedWorld.java

@@ -43,6 +43,9 @@
 import com.github.retrooper.packetevents.wrapper.play.client.WrapperPlayClientPlayerBlockPlacement;
 import com.github.retrooper.packetevents.wrapper.play.client.WrapperPlayClientPlayerDigging;
 import com.github.retrooper.packetevents.wrapper.play.client.WrapperPlayClientUseItem;
+import it.unimi.dsi.fastutil.ints.Int2ObjectMap;
+import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
+import it.unimi.dsi.fastutil.longs.Long2ObjectMap;
 import it.unimi.dsi.fastutil.longs.Long2ObjectOpenHashMap;
 import it.unimi.dsi.fastutil.objects.Object2ObjectLinkedOpenHashMap;
 import org.bukkit.Bukkit;
@@ -55,7 +58,7 @@ public class CompensatedWorld {
     public static final ClientVersion blockVersion = PacketEvents.getAPI().getServerManager().getVersion().toClientVersion();
     private static final WrappedBlockState airData = WrappedBlockState.getByGlobalId(blockVersion, 0);
     public final GrimPlayer player;
-    public final Map<Long, Column> chunks;
+    public final Long2ObjectMap<Column> chunks;
     // Packet locations for blocks
     public Set<PistonData> activePistons = new HashSet<>();
     public Set<ShulkerData> openShulkerBoxes = new HashSet<>();
@@ -70,7 +73,7 @@ public class CompensatedWorld {
     private final Long2ObjectOpenHashMap<BlockPrediction> originalServerBlocks = new Long2ObjectOpenHashMap<>();
     // Blocks the client changed while placing or breaking blocks
     private List<Vector3i> currentlyChangedBlocks = new LinkedList<>();
-    private final Map<Integer, List<Vector3i>> serverIsCurrentlyProcessingThesePredictions = new HashMap<>();
+    private final Int2ObjectMap<List<Vector3i>> serverIsCurrentlyProcessingThesePredictions = new Int2ObjectOpenHashMap<>();
     private final Object2ObjectLinkedOpenHashMap<Pair<Vector3i, DiggingAction>, Vector3d> unackedActions = new Object2ObjectLinkedOpenHashMap<>();
     private boolean isCurrentlyPredicting = false;
     public boolean isRaining = false;
@@ -89,7 +92,7 @@ public void startPredicting() {
     }
 
     public void handlePredictionConfirmation(int prediction) {
-        for (Iterator<Map.Entry<Integer, List<Vector3i>>> it = serverIsCurrentlyProcessingThesePredictions.entrySet().iterator(); it.hasNext(); ) {
+        for (Iterator<Int2ObjectMap.Entry<List<Vector3i>>> it = serverIsCurrentlyProcessingThesePredictions.int2ObjectEntrySet().iterator(); it.hasNext(); ) {
             Map.Entry<Integer, List<Vector3i>> iter = it.next();
             if (iter.getKey() <= prediction) {
                 applyBlockChanges(iter.getValue());

src/main/java/ac/grim/grimac/utils/lists/CorrectingPlayerInventoryStorage.java

@@ -7,6 +7,7 @@
 import com.github.retrooper.packetevents.protocol.item.ItemStack;
 import io.github.retrooper.packetevents.util.SpigotConversionUtil;
 import io.github.retrooper.packetevents.util.folia.FoliaScheduler;
+import it.unimi.dsi.fastutil.ints.Int2IntOpenHashMap;
 import org.bukkit.inventory.InventoryView;
 
 import java.util.*;
@@ -42,7 +43,8 @@ public class CorrectingPlayerInventoryStorage extends InventoryStorage {
     GrimPlayer player;
     // The key for this map is the inventory slot ID
     // The value for this map is the transaction that we care about
-    Map<Integer, Integer> serverIsCurrentlyProcessingThesePredictions = new HashMap<>();
+    // Returns -1 if the entry is null
+    Int2IntOpenHashMap serverIsCurrentlyProcessingThesePredictions = new Int2IntOpenHashMap();
     // A list of predictions the client has made for inventory changes
     // Remove if the server rejects these changes
     Map<Integer, Integer> pendingFinalizedSlot = new ConcurrentHashMap<>();
@@ -54,6 +56,7 @@ public class CorrectingPlayerInventoryStorage extends InventoryStorage {
     public CorrectingPlayerInventoryStorage(GrimPlayer player, int size) {
         super(size);
         this.player = player;
+        this.serverIsCurrentlyProcessingThesePredictions.defaultReturnValue(-1);
     }
 
     // 1.17+ clients send what slots they have changed.  This makes our jobs much easier.
@@ -75,11 +78,11 @@ public void handleServerCorrectSlot(int slotID) {
     @Override
     public void setItem(int item, ItemStack stack) {
         // If there is a more recent change to this one, don't override it
-        Integer finalTransaction = serverIsCurrentlyProcessingThesePredictions.get(item);
+        int finalTransaction = serverIsCurrentlyProcessingThesePredictions.get(item);
 
         // If the server is currently sending a packet to the player AND it is the final change to the slot
         // OR, the client was in control of setting this slot
-        if (finalTransaction == null || player.lastTransactionReceived.get() >= finalTransaction) {
+        if (finalTransaction == -1 || player.lastTransactionReceived.get() >= finalTransaction) {
             // This is the last change for this slot, try to resync this slot if possible
             pendingFinalizedSlot.put(item, GrimAPI.INSTANCE.getTickManager().currentTick + 5);
             serverIsCurrentlyProcessingThesePredictions.remove(item);

src/main/java/ac/grim/grimac/utils/lists/RunningMode.java

@@ -1,6 +1,8 @@
 package ac.grim.grimac.utils.lists;
 
 import ac.grim.grimac.utils.data.Pair;
+import it.unimi.dsi.fastutil.doubles.Double2IntMap;
+import it.unimi.dsi.fastutil.doubles.Double2IntOpenHashMap;
 
 import java.util.HashMap;
 import java.util.Map;
@@ -12,7 +14,7 @@
 // This class calculates the running mode of a list in best case o(1) worst case o(n) time.
 public class RunningMode {
     Queue<Double> addList;
-    Map<Double, Integer> popularityMap = new HashMap<>();
+    Double2IntMap popularityMap = new Double2IntOpenHashMap();
     int maxSize;
 
     private static final double threshold = 1e-3;
@@ -34,10 +36,10 @@ public int getMaxSize() {
     public void add(double value) {
         pop();
 
-        for (Map.Entry<Double, Integer> entry : popularityMap.entrySet()) {
-            if (Math.abs(entry.getKey() - value) < threshold) {
-                entry.setValue(entry.getValue() + 1);
-                addList.add(entry.getKey());
+        for (Double2IntMap.Entry entry : popularityMap.double2IntEntrySet()) {
+            if (Math.abs(entry.getDoubleKey() - value) < threshold) {
+                entry.setValue(entry.getIntValue() + 1);
+                addList.add(entry.getDoubleKey());
                 return;
             }
         }
@@ -49,7 +51,7 @@ public void add(double value) {
 
     private void pop() {
         if (addList.size() >= maxSize) {
-            Double type = addList.poll();
+            double type = addList.poll();
             int popularity = popularityMap.get(type);  // Being null isn't possible
             if (popularity == 1) {
                 popularityMap.remove(type); // Make sure not to leak memory
@@ -63,10 +65,10 @@ public Pair<Double, Integer> getMode() {
         int max = 0;
         Double mostPopular = null;
 
-        for (Map.Entry<Double, Integer> entry : popularityMap.entrySet()) {
-            if (entry.getValue() > max) {
-                max = entry.getValue();
-                mostPopular = entry.getKey();
+        for (Double2IntMap.Entry entry : popularityMap.double2IntEntrySet()) {
+            if (entry.getIntValue() > max) {
+                max = entry.getIntValue();
+                mostPopular = entry.getDoubleKey();
             }
         }