From fb905a15144dbef4e38af33a0ef128f8e5d13afd Mon Sep 17 00:00:00 2001
From: RaphiMC <50594595+RaphiMC@users.noreply.github.com>
Date: Mon, 2 Sep 2024 23:08:39 +0200
Subject: [PATCH] Ensure input buffer isn't modified by VV

---
 .../java/net/raphimc/vialegacy/api/util/PacketUtil.java    | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/main/java/net/raphimc/vialegacy/api/util/PacketUtil.java b/src/main/java/net/raphimc/vialegacy/api/util/PacketUtil.java
index 90923a9..c856b3e 100644
--- a/src/main/java/net/raphimc/vialegacy/api/util/PacketUtil.java
+++ b/src/main/java/net/raphimc/vialegacy/api/util/PacketUtil.java
@@ -19,6 +19,7 @@
 
 import com.viaversion.viaversion.api.protocol.packet.PacketType;
 import com.viaversion.viaversion.api.protocol.packet.PacketWrapper;
+import com.viaversion.viaversion.protocol.packet.PacketWrapperImpl;
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.Unpooled;
 
@@ -29,7 +30,13 @@ public static int calculateLength(final PacketWrapper wrapper) {
         wrapper.setPacketType(null);
 
         final ByteBuf lengthBuffer = Unpooled.buffer();
+        if (wrapper instanceof PacketWrapperImpl impl && impl.getInputBuffer() != null) {
+            impl.getInputBuffer().markReaderIndex();
+        }
         wrapper.writeToBuffer(lengthBuffer);
+        if (wrapper instanceof PacketWrapperImpl impl && impl.getInputBuffer() != null) {
+            impl.getInputBuffer().resetReaderIndex();
+        }
         final int length = lengthBuffer.readableBytes();
         lengthBuffer.release();