Prevent int overflows when adding/removing items

src/main/java/emu/lunarcore/game/inventory/Inventory.java

@@ -24,6 +24,7 @@ import emu.lunarcore.game.player.BasePlayerManager;
 import emu.lunarcore.game.player.Player;
 import emu.lunarcore.server.packet.send.PacketPlayerSyncScNotify;
 import emu.lunarcore.server.packet.send.PacketScenePlaneEventScNotify;
+import emu.lunarcore.util.Utils;
 import it.unimi.dsi.fastutil.ints.Int2ObjectMap;
 import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
 
@@ -233,8 +234,9 @@ public class Inventory extends BasePlayerManager {
                 item.save();
                 return item;
             } else {
-                // Add count
+                // Add count to item
-                existingItem.setCount(Math.min(existingItem.getCount() + item.getCount(), item.getExcel().getPileLimit()));
+                int amount = Utils.safeAdd(existingItem.getCount(), item.getCount(), item.getExcel().getPileLimit(), 0);
+                existingItem.setCount(amount);
                 existingItem.save();
                 return existingItem;
             }
@@ -381,7 +383,7 @@ public class Inventory extends BasePlayerManager {
         if (item.getExcel() == null || item.getExcel().isEquippable()) {
             item.setCount(0);
         } else {
-            item.setCount(item.getCount() - count);
+            item.setCount(Utils.safeSubtract(item.getCount(), count));
         }
 
         if (item.getCount() <= 0) {

src/main/java/emu/lunarcore/game/player/Player.java

@@ -63,6 +63,7 @@ import emu.lunarcore.server.packet.BasePacket;
 import emu.lunarcore.server.packet.CmdId;
 import emu.lunarcore.server.packet.send.*;
 import emu.lunarcore.util.Position;
+import emu.lunarcore.util.Utils;
 import it.unimi.dsi.fastutil.ints.Int2IntMap;
 import it.unimi.dsi.fastutil.ints.Int2IntOpenHashMap;
 import it.unimi.dsi.fastutil.ints.IntOpenHashSet;
@@ -362,22 +363,22 @@ public class Player {
     }
 
     public void addSCoin(int amount) {
-        this.scoin += amount;
+        this.scoin = Utils.safeAdd(this.scoin, amount);
         this.sendPacket(new PacketPlayerSyncScNotify(this));
     }
 
     public void addHCoin(int amount) {
-        this.hcoin += amount;
+        this.hcoin = Utils.safeAdd(this.hcoin, amount);
         this.sendPacket(new PacketPlayerSyncScNotify(this));
     }
 
     public void addMCoin(int amount) {
-        this.mcoin += amount;
+        this.mcoin = Utils.safeAdd(this.mcoin, amount);
         this.sendPacket(new PacketPlayerSyncScNotify(this));
     }
     
     public void addTalentPoints(int amount) {
-        this.talentPoints += amount;
+        this.talentPoints = Utils.safeAdd(this.talentPoints, amount);
         this.sendPacket(new PacketSyncRogueVirtualItemInfoScNotify(this));
     }
 
@@ -440,7 +441,7 @@ public class Player {
     }
     
     public void addStamina(int amount) {
-        this.stamina += amount;
+        this.stamina = Utils.safeAdd(this.stamina, amount);
         this.sendPacket(new PacketStaminaInfoScNotify(this));
     }
     

src/main/java/emu/lunarcore/util/Utils.java

@@ -121,6 +121,44 @@ public class Utils {
 
         return i;
     }
+    
+    /**
+     * Add 2 integers without overflowing
+     */
+    public static int safeAdd(int a, int b) {
+        return safeAdd(a, b, Integer.MAX_VALUE, Integer.MIN_VALUE);
+    }
+    
+    public static int safeAdd(int a, int b, long max, long min) {
+        long sum = (long) a + (long) b;
+        
+        if (sum > max) {
+            return (int) max;
+        } else if (sum < min) {
+            return (int) min;
+        }
+        
+        return (int) sum;
+    }
+    
+    /**
+     * Subtract 2 integers without overflowing
+     */
+    public static int safeSubtract(int a, int b) {
+        return safeSubtract(a, b, Integer.MAX_VALUE, Integer.MIN_VALUE);
+    }
+    
+    public static int safeSubtract(int a, int b, long max, long min) {
+        long sum = (long) a - (long) b;
+        
+        if (sum > max) {
+            return (int) max;
+        } else if (sum < min) {
+            return (int) min;
+        }
+        
+        return (int) sum;
+    }
 
     public static double generateRandomDouble() {
         return ThreadLocalRandom.current().nextDouble();