From 71d7004d0cb6022fd46813e5571bfee6aac4b732 Mon Sep 17 00:00:00 2001
From: embeddedt <42941056+embeddedt@users.noreply.github.com>
Date: Tue, 2 May 2023 19:19:57 -0400
Subject: [PATCH] Shrink oversized PalettedContainers

---
 .../PalettedContainerMixin.java               | 39 +++++++++++++++++++
 .../main/resources/modernfix.accesswidener    |  1 +
 2 files changed, 40 insertions(+)
 create mode 100644 common/src/main/java/org/embeddedt/modernfix/common/mixin/perf/compact_bit_storage/PalettedContainerMixin.java

diff --git a/common/src/main/java/org/embeddedt/modernfix/common/mixin/perf/compact_bit_storage/PalettedContainerMixin.java b/common/src/main/java/org/embeddedt/modernfix/common/mixin/perf/compact_bit_storage/PalettedContainerMixin.java
new file mode 100644
index 00000000..0a74c573
--- /dev/null
+++ b/common/src/main/java/org/embeddedt/modernfix/common/mixin/perf/compact_bit_storage/PalettedContainerMixin.java
@@ -0,0 +1,39 @@
+package org.embeddedt.modernfix.common.mixin.perf.compact_bit_storage;
+
+import net.minecraft.network.FriendlyByteBuf;
+import net.minecraft.world.level.chunk.PalettedContainer;
+import org.jetbrains.annotations.Nullable;
+import org.objectweb.asm.Opcodes;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+import org.spongepowered.asm.mixin.injection.callback.LocalCapture;
+
+@Mixin(PalettedContainer.class)
+public abstract class PalettedContainerMixin<T> {
+    @Shadow private volatile PalettedContainer.Data<T> data;
+
+    @Shadow protected abstract PalettedContainer.Data<T> createOrReuseData(@Nullable PalettedContainer.Data<T> data, int id);
+
+    @Inject(method = "read(Lnet/minecraft/network/FriendlyByteBuf;)V", at = @At(value = "FIELD", target = "Lnet/minecraft/world/level/chunk/PalettedContainer;data:Lnet/minecraft/world/level/chunk/PalettedContainer$Data;", opcode = Opcodes.PUTFIELD, shift = At.Shift.AFTER), locals = LocalCapture.CAPTURE_FAILHARD)
+    private void validateData(FriendlyByteBuf buffer, CallbackInfo ci, int i) {
+        if(i <= 1)
+            return;
+        long[] storArray = this.data.storage().getRaw();
+        boolean empty = true;
+        for (long l : storArray) {
+            if (l != 0) {
+                empty = false;
+                break;
+            }
+        }
+        if(empty && storArray.length > 0) {
+            /* it means the chunk is oversized and wasting memory, take the ID out of the palette and recreate a smaller chunk */
+            T value = this.data.palette().valueFor(0);
+            this.data = this.createOrReuseData(null, 0);
+            this.data.palette().idFor(value);
+        }
+    }
+}
diff --git a/common/src/main/resources/modernfix.accesswidener b/common/src/main/resources/modernfix.accesswidener
index 2949c629..3178cc0e 100644
--- a/common/src/main/resources/modernfix.accesswidener
+++ b/common/src/main/resources/modernfix.accesswidener
@@ -35,3 +35,4 @@ accessible method net/minecraft/resources/ResourceKey <init> (Lnet/minecraft/res
 accessible method net/minecraft/client/renderer/texture/TextureAtlasSprite <init> (Lnet/minecraft/client/renderer/texture/TextureAtlas;Lnet/minecraft/client/renderer/texture/TextureAtlasSprite$Info;IIIIILcom/mojang/blaze3d/platform/NativeImage;)V
 accessible field net/minecraft/client/renderer/block/model/BlockModel GSON Lcom/google/gson/Gson;
 accessible class net/minecraft/server/level/ChunkMap$DistanceManager
+accessible class net/minecraft/world/level/chunk/PalettedContainer$Data
\ No newline at end of file