cuberite-2a/src/Protocol/ChunkDataSerializer.cpp

// ChunkDataSerializer.cpp

// Implements the cChunkDataSerializer class representing the object that can:
//  - serialize chunk data to different protocol versions
//  - cache such serialized data for multiple clients

#include "Globals.h"
#include "ChunkDataSerializer.h"
#include "zlib/zlib.h"




cChunkDataSerializer::cChunkDataSerializer(
	const cChunkDef::BlockTypes   & a_BlockTypes,
	const cChunkDef::BlockNibbles & a_BlockMetas,
	const cChunkDef::BlockNibbles & a_BlockLight,
	const cChunkDef::BlockNibbles & a_BlockSkyLight,
	const unsigned char *           a_BiomeData
) :
	m_BlockTypes(a_BlockTypes),
	m_BlockMetas(a_BlockMetas),
	m_BlockLight(a_BlockLight),
	m_BlockSkyLight(a_BlockSkyLight),
	m_BiomeData(a_BiomeData)
{
}




const AString & cChunkDataSerializer::Serialize(int a_Version)
{
	Serializations::const_iterator itr = m_Serializations.find(a_Version);
	if (itr != m_Serializations.end())
	{
		return itr->second;
	}
	
	AString data;
	switch (a_Version)
	{
		case RELEASE_1_2_5: Serialize29(data); break;
		case RELEASE_1_3_2: Serialize39(data); break;
		// TODO: Other protocol versions may serialize the data differently; implement here
		
		default:
		{
			LOGERROR("cChunkDataSerializer::Serialize(): Unknown version: %d", a_Version);
			ASSERT(!"Unknown chunk data serialization version");
			break;
		}
	}
	m_Serializations[a_Version] = data;
	return m_Serializations[a_Version];
}





void cChunkDataSerializer::Serialize29(AString & a_Data)
{
	// TODO: Do not copy data and then compress it; rather, compress partial blocks of data (zlib *can* stream)

	const int BiomeDataSize    = cChunkDef::Width * cChunkDef::Width;
	const int MetadataOffset   = sizeof(m_BlockTypes);
	const int BlockLightOffset = MetadataOffset   + sizeof(m_BlockMetas);
	const int SkyLightOffset   = BlockLightOffset + sizeof(m_BlockLight);
	const int BiomeOffset      = SkyLightOffset   + sizeof(m_BlockSkyLight);
	const int DataSize         = BiomeOffset      + BiomeDataSize;
	
	// Temporary buffer for the composed data:
	char AllData [DataSize];

	memcpy(AllData, m_BlockTypes, sizeof(m_BlockTypes));
	memcpy(AllData + MetadataOffset,   m_BlockMetas,    sizeof(m_BlockMetas));
	memcpy(AllData + BlockLightOffset, m_BlockLight,    sizeof(m_BlockLight));
	memcpy(AllData + SkyLightOffset,   m_BlockSkyLight, sizeof(m_BlockSkyLight));
	memcpy(AllData + BiomeOffset,      m_BiomeData,     BiomeDataSize);

	// Compress the data:
	// In order not to use allocation, use a fixed-size buffer, with the size
	// that uses the same calculation as compressBound():
	const uLongf CompressedMaxSize = DataSize + (DataSize >> 12) + (DataSize >> 14) + (DataSize >> 25) + 16;
	char CompressedBlockData[CompressedMaxSize];

	uLongf CompressedSize = compressBound(DataSize);
	
	// Run-time check that our compile-time guess about CompressedMaxSize was enough:
	ASSERT(CompressedSize <= CompressedMaxSize);
	
	compress2((Bytef*)CompressedBlockData, &CompressedSize, (const Bytef*)AllData, sizeof(AllData), Z_DEFAULT_COMPRESSION);

	// Now put all those data into a_Data:
	
	// "Ground-up continuous", or rather, "biome data present" flag:
	a_Data.push_back('\x01');
	
	// Two bitmaps; we're aways sending the full chunk with no additional data, so the bitmaps are 0xffff and 0, respectively
	// Also, no endian flipping is needed because of the const values
	unsigned short BitMap1 = 0xffff;
	unsigned short BitMap2 = 0;
	a_Data.append((const char *)&BitMap1, sizeof(short));
	a_Data.append((const char *)&BitMap2, sizeof(short));
	
	UInt32 CompressedSizeBE = htonl((UInt32)CompressedSize);
	a_Data.append((const char *)&CompressedSizeBE, sizeof(CompressedSizeBE));
	
	Int32 UnusedInt32 = 0;
	a_Data.append((const char *)&UnusedInt32,      sizeof(UnusedInt32));
	
	a_Data.append(CompressedBlockData, CompressedSize);
}





void cChunkDataSerializer::Serialize39(AString & a_Data)
{
	// TODO: Do not copy data and then compress it; rather, compress partial blocks of data (zlib *can* stream)

	const int BiomeDataSize    = cChunkDef::Width * cChunkDef::Width;
	const int MetadataOffset   = sizeof(m_BlockTypes);
	const int BlockLightOffset = MetadataOffset   + sizeof(m_BlockMetas);
	const int SkyLightOffset   = BlockLightOffset + sizeof(m_BlockLight);
	const int BiomeOffset      = SkyLightOffset   + sizeof(m_BlockSkyLight);
	const int DataSize         = BiomeOffset      + BiomeDataSize;
	
	// Temporary buffer for the composed data:
	char AllData [DataSize];

	memcpy(AllData, m_BlockTypes, sizeof(m_BlockTypes));
	memcpy(AllData + MetadataOffset,   m_BlockMetas,    sizeof(m_BlockMetas));
	memcpy(AllData + BlockLightOffset, m_BlockLight,    sizeof(m_BlockLight));
	memcpy(AllData + SkyLightOffset,   m_BlockSkyLight, sizeof(m_BlockSkyLight));
	memcpy(AllData + BiomeOffset,      m_BiomeData,     BiomeDataSize);

	// Compress the data:
	// In order not to use allocation, use a fixed-size buffer, with the size
	// that uses the same calculation as compressBound():
	const uLongf CompressedMaxSize = DataSize + (DataSize >> 12) + (DataSize >> 14) + (DataSize >> 25) + 16;
	char CompressedBlockData[CompressedMaxSize];

	uLongf CompressedSize = compressBound(DataSize);
	
	// Run-time check that our compile-time guess about CompressedMaxSize was enough:
	ASSERT(CompressedSize <= CompressedMaxSize);
	
	compress2((Bytef*)CompressedBlockData, &CompressedSize, (const Bytef*)AllData, sizeof(AllData), Z_DEFAULT_COMPRESSION);

	// Now put all those data into a_Data:
	
	// "Ground-up continuous", or rather, "biome data present" flag:
	a_Data.push_back('\x01');
	
	// Two bitmaps; we're aways sending the full chunk with no additional data, so the bitmaps are 0xffff and 0, respectively
	// Also, no endian flipping is needed because of the const values
	unsigned short BitMap1 = 0xffff;
	unsigned short BitMap2 = 0;
	a_Data.append((const char *)&BitMap1, sizeof(short));
	a_Data.append((const char *)&BitMap2, sizeof(short));
	
	UInt32 CompressedSizeBE = htonl((UInt32)CompressedSize);
	a_Data.append((const char *)&CompressedSizeBE, sizeof(CompressedSizeBE));
	
	// Unlike 29, 39 doesn't have the "unused" int
	
	a_Data.append(CompressedBlockData, CompressedSize);
}