From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Wed, 4 Jul 2018 02:13:59 -0400
Subject: [PATCH] Store counts for each Entity/Block Entity Type

Opens door for future patches to optimize performance

diff --git a/src/main/java/net/minecraft/world/level/chunk/LevelChunk.java b/src/main/java/net/minecraft/world/level/chunk/LevelChunk.java
index ae08fcce66d50d7f61bc3bd4a0e2547d56f53e82..00ce55c17980da87a3834f952475a766543506b0 100644
--- a/src/main/java/net/minecraft/world/level/chunk/LevelChunk.java
+++ b/src/main/java/net/minecraft/world/level/chunk/LevelChunk.java
@@ -90,15 +90,19 @@ public class LevelChunk implements ChunkAccess {
     }
 
     // Paper start
+    public final co.aikar.util.Counter<String> entityCounts = new co.aikar.util.Counter<>();
+    public final co.aikar.util.Counter<String> tileEntityCounts = new co.aikar.util.Counter<>();
     private class TileEntityHashMap extends java.util.HashMap<BlockPos, BlockEntity> {
         @Override
         public BlockEntity put(BlockPos key, BlockEntity value) {
             BlockEntity replaced = super.put(key, value);
             if (replaced != null) {
                 replaced.setCurrentChunk(null);
+                tileEntityCounts.decrement(replaced.getMinecraftKeyString());
             }
             if (value != null) {
                 value.setCurrentChunk(LevelChunk.this);
+                tileEntityCounts.increment(value.getMinecraftKeyString());
             }
             return replaced;
         }
@@ -108,6 +112,7 @@ public class LevelChunk implements ChunkAccess {
             BlockEntity removed = super.remove(key);
             if (removed != null) {
                 removed.setCurrentChunk(null);
+                tileEntityCounts.decrement(removed.getMinecraftKeyString());
             }
             return removed;
         }
@@ -528,6 +533,7 @@ public class LevelChunk implements ChunkAccess {
             k = this.entitySlices.length - 1;
         }
 
+        if (!entity.inChunk || entity.getCurrentChunk() != this) entityCounts.increment(entity.getMinecraftKeyString()); // Paper
         entity.inChunk = true;
         entity.setCurrentChunk(this); // Paper
         entity.xChunk = this.chunkPos.x;
@@ -562,6 +568,7 @@ public class LevelChunk implements ChunkAccess {
         if (!this.entitySlices[section].remove(entity)) {
             return;
         }
+        entityCounts.decrement(entity.getMinecraftKeyString());
         // Paper end
         this.entities.remove(entity); // Paper
     }