From a16143b109a5099f59c969c98ed7299fbf4cf84c Mon Sep 17 00:00:00 2001
From: Joseph Hirschfeld <joe@ibj.io>
Date: Thu, 3 Mar 2016 02:39:54 -0600
Subject: [PATCH] Change implementation of (tile)entity removal list

use sets for faster removal

diff --git a/src/main/java/net/minecraft/server/World.java b/src/main/java/net/minecraft/server/World.java
index a80acbb6a5..09cf98ccdd 100644
--- a/src/main/java/net/minecraft/server/World.java
+++ b/src/main/java/net/minecraft/server/World.java
@@ -68,11 +68,11 @@ public abstract class World implements IEntityAccess, GeneratorAccess, IIBlockAc
         }
     };
     // Spigot end
-    protected final List<Entity> g = Lists.newArrayList();
+    protected final Set<Entity> g = com.google.common.collect.Sets.newHashSet(); // Paper
     public final List<TileEntity> tileEntityList = Lists.newArrayList();
     public final List<TileEntity> tileEntityListTick = Lists.newArrayList();
     private final List<TileEntity> c = Lists.newArrayList();
-    private final List<TileEntity> tileEntityListUnload = Lists.newArrayList();
+    private final Set<TileEntity> tileEntityListUnload = com.google.common.collect.Sets.newHashSet(); // Paper
     public final List<EntityHuman> players = Lists.newArrayList();
     public final List<Entity> k = Lists.newArrayList();
     protected final IntHashMap<Entity> entitiesById = new IntHashMap<>();
@@ -1095,20 +1095,21 @@ public abstract class World implements IEntityAccess, GeneratorAccess, IIBlockAc
         this.entityList.removeAll(this.g);
 
         int j;
-
-        for (i = 0; i < this.g.size(); ++i) {
-            entity = (Entity) this.g.get(i);
+        // Paper start - Set based removal lists
+        for (Iterator<Entity> it = this.g.iterator(); it.hasNext() ; ) {
+            entity = it.next(); // Paper
             int k = entity.chunkX;
 
             j = entity.chunkZ;
             if (entity.inChunk && this.isChunkLoaded(k, j, true)) {
                 this.getChunkAt(k, j).b(entity);
             }
-        }
+        //} // Paper - merge
 
-        for (i = 0; i < this.g.size(); ++i) {
-            this.c((Entity) this.g.get(i));
+        //for (Entity e : this.g) { // Paper - merge
+            this.c(entity); // Paper use entity
         }
+        // Paper end
 
         this.g.clear();
         this.p_();
-- 
2.21.0