public void Init()
{
FileInfo fi = new FileInfo(_filename);
if (!fi.Directory.Exists)
{
fi.Directory.Create();
}
_fs = fi.Open(FileMode.OpenOrCreate, FileAccess.ReadWrite);
if (_fs.Length < SectorToByte(2))
{
byte[] headByte = Enumerable.Repeat((byte)0x00, (int)SectorToByte(2)).ToArray();
_fs.Position = 0;
_fs.Write(headByte, 0, headByte.Length);
}
_headData = new ChunkHeadData[REGION_WIDTH, REGION_DEPTH];
_useSector = new ArrayList(new bool[ByteToSector(_fs.Length)]);
_useSector[0] = true;
_useSector[1] = true;
for (int x = 0; x < REGION_WIDTH; x++)
{
for (int z = 0; z < REGION_DEPTH; z++)
{
_headData[x, z] = new ChunkHeadData(x, z);
ReadHeadData(x, z);
}
}
_cs = new ChunkStream();
}
//获取到的块数据
public bool GetChunkData(int x, int z, Chunk chunk)
{
if (_headData[x, z].status == ChunkDataStatus.Not_Create)
{
return(false);
}
_fs.Position = SectorToByte(_headData[x, z].BlockOffset) + 5;
_cs.SetLength(0);
_cs.Write(_fs, _headData[x, z].Length);
_cs.Position = 0;
IMTBCompress compress = MTBCompressFactory.GetCompress(_headData[x, z].CompressionType);
_cs = (ChunkStream)compress.Decompress(_cs);
_cs.Position = 0;
chunk.Deserialize(_cs);
return(true);
}
//保存块的字节数据
public void SaveChunkData(int x, int z, Chunk chunk)
{
_cs.SetLength(0);
chunk.Serialize(_cs);
_cs.Position = 0;
IMTBCompress compress = MTBCompressFactory.GetCompress(_compressType);
_cs = (ChunkStream)compress.Encompress(_cs);
byte[] chunkSize = new byte[4];
Serialization.WriteIntToByteArr(chunkSize, (int)_cs.Length);
int singleChunkLength = (int)_cs.Length + 5;
int blockLength = ByteToSector(singleChunkLength);
ClearChunkData(x, z);
int blockOffset = GetChunkCanSavedSector(blockLength);
long blockOffsetStartByteIndex = SectorToByte(blockOffset);
_fs.Position = blockOffsetStartByteIndex;
//写入区块长度
_fs.Write(chunkSize, 0, chunkSize.Length);
//写入压缩格式
_fs.WriteByte((byte)compress.CompressType);
//写入区块压缩数据
_cs.Position = 0;
_cs.Read(_fs, (int)_cs.Length);
int startPosition = (x * REGION_DEPTH + z) * 4;
_fs.Position = startPosition;
byte[] blockOffsetByte = new byte[4];
Serialization.WriteIntToByteArr(blockOffsetByte, blockOffset);
_fs.Write(blockOffsetByte, 0, 3);
_fs.WriteByte((byte)blockLength);
//更新可存储标志，并将块后面不足一个扇区的部分写0x00
for (int i = blockOffset; i < blockOffset + blockLength; i++)
{
_useSector[i] = true;
}
long chunkEnd = blockOffsetStartByteIndex + singleChunkLength;
long sectorEnd = blockOffsetStartByteIndex + SectorToByte(blockLength);
if (chunkEnd < sectorEnd)
{
_fs.Position = chunkEnd;
byte[] extendByte = Enumerable.Repeat((byte)0x00, (int)(sectorEnd - chunkEnd)).ToArray();
_fs.Write(extendByte, 0, extendByte.Length);
}
//截取文件最后没有使用的扇区
int lastUseSectorIndex = GetLastUseSectorIndex();
if (lastUseSectorIndex != -1 && lastUseSectorIndex != _useSector.Count - 1)
{
int truncatedIndex = lastUseSectorIndex + 1;
_useSector.RemoveRange(truncatedIndex, _useSector.Count - truncatedIndex);
_fs.SetLength(SectorToByte(truncatedIndex));
}
//更新headData数据
_headData[x, z].BlockOffset = blockOffset;
_headData[x, z].BlockLength = (byte)blockLength;
_headData[x, z].Length = (int)_cs.Length;
_headData[x, z].status = ChunkDataStatus.OK;
_headData[x, z].CompressionType = compress.CompressType;
}