From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: tr7zw <tr7zw@live.de>
Date: Thu, 25 Jun 2020 23:40:12 +0200
Subject: [PATCH] Heavily optimize furnance fuel and recipe lookups

Co-authored-by: Mykyta Komarn <nkomarn@hotmail.com>

diff --git a/src/main/java/net/minecraft/server/TileEntityFurnace.java b/src/main/java/net/minecraft/server/TileEntityFurnace.java
index 1d3c2dd93657fb5dc71ee6b444c585b54619d1e8..77ea56c5a25fe09a1721429d42965ad34d905870 100644
--- a/src/main/java/net/minecraft/server/TileEntityFurnace.java
+++ b/src/main/java/net/minecraft/server/TileEntityFurnace.java
@@ -83,7 +83,14 @@ public abstract class TileEntityFurnace extends TileEntityContainer implements I
         this.c = recipes;
     }
 
+    private static Object2IntOpenHashMap<Item> cachedFuelMap = null; // Yatopia
+
     public static Map<Item, Integer> f() {
+        // Yatopia start
+	    if(cachedFuelMap != null) {
+		    return cachedFuelMap;
+	    }
+	    // Yatopia end
         Map<Item, Integer> map = Maps.newLinkedHashMap();
 
         a(map, (IMaterial) Items.LAVA_BUCKET, 20000);
@@ -146,6 +153,7 @@ public abstract class TileEntityFurnace extends TileEntityContainer implements I
         a(map, (IMaterial) Blocks.FLETCHING_TABLE, 300);
         a(map, (IMaterial) Blocks.SMITHING_TABLE, 300);
         a(map, (IMaterial) Blocks.COMPOSTER, 300);
+        cachedFuelMap = new Object2IntOpenHashMap<>(map); // Yatopia
         return map;
     }
 
@@ -271,7 +279,10 @@ public abstract class TileEntityFurnace extends TileEntityContainer implements I
                     this.cookTime = MathHelper.clamp(this.cookTime - 2, 0, this.cookTimeTotal);
                 }
             } else {
-                IRecipe irecipe = this.world.getCraftingManager().craft((Recipes<RecipeCooking>) this.c, this, this.world).orElse(null); // Eclipse fail
+                // Yatopia start - used cached recipe if possible, otherwise look up
+                IRecipe irecipe = getCurrentRecipe();
+                if (irecipe == null) irecipe = this.world.getCraftingManager().craft((Recipes<RecipeCooking>) this.c, this, this.world).orElse(null); // Eclipse fail
+                // Yatopia end
 
                 if (!this.isBurning() && this.canBurn(irecipe)) {
                     // CraftBukkit start
@@ -597,4 +608,18 @@ public abstract class TileEntityFurnace extends TileEntityContainer implements I
         }
 
     }
+
+    // Yatopia start - cache recipe
+    private IRecipe cachedRecipe = null;
+
+    @Override
+    public IRecipe getCurrentRecipe() {
+        return cachedRecipe;
+    }
+
+    @Override
+    public void setCurrentRecipe(IRecipe recipe) {
+        cachedRecipe = recipe;
+    }
+    // Yatopia end
 }