From b691c43c44ff180d10e7d4a9afc83b98551ff586 Mon Sep 17 00:00:00 2001
From: daoge_cmd <3523206925@qq.com>
Date: Sun, 1 Mar 2026 12:16:08 +0800
Subject: Initial commit

---
 Minecraft.World/BlockRegionUpdatePacket.cpp | 157 ++++++++++++++++++++++++++++
 1 file changed, 157 insertions(+)
 create mode 100644 Minecraft.World/BlockRegionUpdatePacket.cpp

(limited to 'Minecraft.World/BlockRegionUpdatePacket.cpp')

diff --git a/Minecraft.World/BlockRegionUpdatePacket.cpp b/Minecraft.World/BlockRegionUpdatePacket.cpp
new file mode 100644
index 00000000..d85321a5
--- /dev/null
+++ b/Minecraft.World/BlockRegionUpdatePacket.cpp
@@ -0,0 +1,157 @@
+#include "stdafx.h"
+#include <iostream>
+#include <exception>
+#include "InputOutputStream.h"
+#include "net.minecraft.world.level.h"
+#include "compression.h"
+#include "PacketListener.h"
+#include "BlockRegionUpdatePacket.h"
+#include "LevelChunk.h"
+#include "DataLayer.h"
+#include "Dimension.h"
+
+
+
+BlockRegionUpdatePacket::~BlockRegionUpdatePacket()
+{
+	delete [] buffer.data;
+}
+
+BlockRegionUpdatePacket::BlockRegionUpdatePacket()
+{
+	shouldDelay = true;
+	x = 0;
+	y = 0;
+	z = 0;
+	xs = 0;
+	ys = 0;
+	zs = 0;
+	bIsFullChunk = false;
+}
+
+BlockRegionUpdatePacket::BlockRegionUpdatePacket(int x, int y, int z, int xs, int ys, int zs, Level *level)
+{
+	
+	shouldDelay = true;
+	this->x = x;
+	this->y = y;
+	this->z = z;
+	this->xs = xs;
+	this->ys = ys;
+	this->zs = zs;
+	bIsFullChunk = false;
+	levelIdx = ( ( level->dimension->id == 0 ) ? 0 : ( (level->dimension->id == -1) ? 1 : 2 ) );
+
+	// 4J - if we are compressing a full chunk, re-order the blocks so that they compress better
+	// TODO - we should be using compressed data directly here rather than decompressing first and then recompressing...
+	byteArray rawBuffer;
+
+	if( xs == 16 && ys == Level::maxBuildHeight && zs == 16 && ( ( x & 15 ) == 0 ) && ( y == 0 ) && ( ( z & 15 ) == 0 ) ) 
+	{
+		bIsFullChunk = true;
+
+		LevelChunk *lc = level->getChunkAt(x,z);
+		rawBuffer = lc->getReorderedBlocksAndData(x&0xF, y, z&0xF, xs, this->ys, zs);
+	}
+	else
+	{
+		MemSect(50);
+		rawBuffer = level->getBlocksAndData(x, y, z, xs, ys, zs, false);
+		MemSect(0);
+	}
+
+	if(rawBuffer.length == 0)
+	{
+		size = 0;
+		buffer = byteArray();
+	}
+	else
+	{
+		// We don't know how this will compress - just make a fixed length buffer to initially decompress into
+		// Some small sets of blocks can end up compressing into something bigger than their source
+		unsigned char *ucTemp = new unsigned char[(256 * 16 * 16 * 5)/2];
+		unsigned int inputSize = (256 * 16 * 16 * 5)/2;
+	
+		Compression::getCompression()->CompressLZXRLE(ucTemp, &inputSize, rawBuffer.data, (unsigned int) rawBuffer.length);
+		//app.DebugPrintf("Chunk (%d,%d) compressed from %d to size %d\n", x>>4, z>>4, rawBuffer.length, inputSize);
+		unsigned char *ucTemp2 = new unsigned char[inputSize];
+		memcpy(ucTemp2,ucTemp,inputSize);
+		delete [] ucTemp;
+		buffer = byteArray(ucTemp2,inputSize);
+		delete [] rawBuffer.data;
+		size = inputSize;
+	}
+}
+
+void BlockRegionUpdatePacket::read(DataInputStream *dis) //throws IOException
+{
+	bIsFullChunk = dis->readBoolean();
+	x = dis->readInt();
+	y = dis->readShort();
+	z = dis->readInt();
+	xs = dis->read() + 1;
+	ys = dis->read() + 1;
+	zs = dis->read() + 1;
+
+	size = dis->readInt();
+	levelIdx = ( size >> 30 ) & 3;
+	size &= 0x3fffffff;
+
+	if(size == 0)
+	{
+		buffer = byteArray();
+	}
+	else
+	{
+		byteArray compressedBuffer(size);
+		bool success = dis->readFully(compressedBuffer);
+
+		int bufferSize = xs * ys * zs * 5/2;
+		// Add the size of the biome data if it's a full chunk
+		if(bIsFullChunk) bufferSize += (16*16);
+		buffer = byteArray(bufferSize);
+		unsigned int outputSize = buffer.length;
+
+		if( success )
+		{
+			Compression::getCompression()->DecompressLZXRLE( buffer.data, &outputSize, compressedBuffer.data, size);
+		}
+		else
+		{
+			app.DebugPrintf("Not decompressing packet that wasn't fully read\n");
+		}
+
+	//	printf("Block (%d %d %d), (%d %d %d) coming in decomp from %d to %d\n",x,y,z,xs,ys,zs,size,outputSize);
+	
+
+		delete [] compressedBuffer.data;
+		assert(buffer.length == outputSize);
+	}
+}
+
+void BlockRegionUpdatePacket::write(DataOutputStream *dos) // throws IOException
+{
+	dos->writeBoolean(bIsFullChunk);
+	dos->writeInt(x);
+	dos->writeShort(y);
+	dos->writeInt(z);
+	dos->write(xs - 1);
+	dos->write(ys - 1);
+	dos->write(zs - 1);
+
+	int sizeAndLevel = size;
+	sizeAndLevel |= ( levelIdx << 30 );
+	dos->writeInt(sizeAndLevel);
+	dos->write(buffer, 0, size);
+}
+
+void BlockRegionUpdatePacket::handle(PacketListener *listener)
+{
+	listener->handleBlockRegionUpdate(shared_from_this());
+}
+
+int BlockRegionUpdatePacket::getEstimatedSize() 
+{
+	return 17 + size;
+}
+
-- 
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