From 96c3ef3e341be50cc9bf4fba2b6aac02cd22566b Mon Sep 17 00:00:00 2001
From: deathcap <deathcap@gmx.co.uk>
Date: Tue, 16 Feb 2016 00:51:18 -0800
Subject: [PATCH] compressedNbt: clear OS field in gzip header to match MC

http://tools.ietf.org/html/rfc1952 defines the gzip header, which has an
"OS (Operating System)" byte; node.js zlib https://nodejs.org/api/zlib.html
sets OS to 0x03 (Unix) but Minecraft leaves it cleared to 0x00. To match
Minecraft behavior byte-for-byte (important for examples/proxy/proxy.js),
make sure this byte is cleared when writing compressedNbt.
---
 src/datatypes/minecraft.js | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/datatypes/minecraft.js b/src/datatypes/minecraft.js
index 569e5d2..ed1439a 100644
--- a/src/datatypes/minecraft.js
+++ b/src/datatypes/minecraft.js
@@ -77,6 +77,7 @@ function writeCompressedNbt(value, buffer, offset) {
   nbt.proto.write(value,nbtBuffer,0,"nbt");
 
   const compressedNbt = zlib.gzipSync(nbtBuffer); // TODO: async
+  compressedNbt.writeUInt8(0, 9); // clear the OS field to match MC
 
   buffer.writeInt16BE(compressedNbt.length,offset);
   compressedNbt.copy(buffer,offset+2);