Leaf/leaf-server/minecraft-patches/features/0133-Replace-IdMapper-id-map-with-optimized-collection.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Taiyou06 <kaandindar21@gmail.com>
Date: Mon, 24 Feb 2025 16:33:46 +0100
Subject: [PATCH] Replace IdMapper id map with optimized collection


diff --git a/net/minecraft/core/IdMapper.java b/net/minecraft/core/IdMapper.java
index 439dc29b8ee8a1dc2ec63c00a9727a37bb697bad..be80e0bd9b44f7a04075827f0a8f22a126031c07 100644
--- a/net/minecraft/core/IdMapper.java
+++ b/net/minecraft/core/IdMapper.java
@@ -11,7 +11,7 @@ import javax.annotation.Nullable;
 
 public class IdMapper<T> implements IdMap<T> {
     private int nextId;
-    private final Reference2IntMap<T> tToId;
+    private final it.unimi.dsi.fastutil.objects.Object2IntOpenCustomHashMap<T> tToId; // Leaf - Optimize IdMapper
     private final List<T> idToT;
 
     public IdMapper() {
@@ -20,7 +20,22 @@ public class IdMapper<T> implements IdMap<T> {
 
     public IdMapper(int expectedSize) {
         this.idToT = Lists.newArrayListWithExpectedSize(expectedSize);
-        this.tToId = new Reference2IntOpenHashMap<>(expectedSize);
+        // Leaf start - Replace IdMapper id map with optimized collection
+        this.tToId = new it.unimi.dsi.fastutil.objects.Object2IntOpenCustomHashMap<>(
+            expectedSize,
+            new it.unimi.dsi.fastutil.Hash.Strategy<>() {
+                @Override
+                public int hashCode(T o) {
+                    return System.identityHashCode(o);
+                }
+
+                @Override
+                public boolean equals(T a, T b) {
+                    return a == b;
+                }
+            }
+        );
+        // Leaf end - Replace IdMapper id map with optimized collection
         this.tToId.defaultReturnValue(-1);
     }