// todo: this needs reimplemented. There is no such thing as a binary chunk index, and the chunk may not be in 0, 1, 2 order
// Moves stream position to binary chunk location
public static ChunkInfo SeekToBinaryChunk(Stream stream, int binaryChunkIndex, long startPosition = 0)
{
stream.Position = startPosition + 4; // start after magic number chunk
GLBHeader header = ParseGLBHeader(stream);
uint chunkOffset = 12; // sizeof(GLBHeader) + magic number
uint chunkLength = 0;
for (int i = 0; i < binaryChunkIndex + 2; ++i)
{
chunkOffset += chunkLength;
stream.Position = chunkOffset;
chunkLength = GetUInt32(stream);
chunkOffset += 8; // to account for chunk length (4 bytes) and type (4 bytes)
}
// Load Binary Chunk
if (chunkOffset + chunkLength <= header.FileLength)
{
ChunkFormat chunkType = (ChunkFormat)GetUInt32(stream);
if (chunkType != ChunkFormat.BIN)
{
throw new GLTFHeaderInvalidException("Second chunk must be of type BIN if present");
}
return(new ChunkInfo
{
StartPosition = stream.Position - CHUNK_HEADER_SIZE,
Length = chunkLength,
Type = chunkType
});
}
throw new GLTFHeaderInvalidException("File length does not match chunk header.");
}
public Column(ChunkFormat format, MemoryStream chunkDataStream, DateTime timestamp)
{
Modified = timestamp;
var stream = GetDecompressedStream(format, chunkDataStream); //TODO: Need to dispose of this manually?
_nbtDoc = NbtDocument.LoadDocument(stream);
var level = _nbtDoc.Query <TagCompound>("Level");
XWorld = level.GetIntValue("xPos") * 16;
ZWorld = level.GetIntValue("zPos") * 16;
var terrainPopulated = level.GetByte("TerrainPopulated");
if (terrainPopulated != null)
{
TerrainPopulated = terrainPopulated.Value == 1;
}
else
{
TerrainPopulated = level.GetLongValue("LastUpdate") > 0;
}
}
private Stream GetDecompressedStream(ChunkFormat format, MemoryStream chunkDataStream)
{
var outputStream = new MemoryStream();
switch (format)
{
case ChunkFormat.ZLIB_DEFLATE:
if (chunkDataStream.ReadByte() != 0x78 || chunkDataStream.ReadByte() != 0x9C) //zlib header
{
throw new Exception("Incorrect zlib header");
}
using (var deflateStream = new DeflateStream(chunkDataStream, CompressionMode.Decompress, false))
{
deflateStream.CopyTo(outputStream);
}
break;
case ChunkFormat.GZIP:
using (var gzipStream = new GZipStream(chunkDataStream, CompressionMode.Decompress, false))
{
gzipStream.CopyTo(outputStream);
}
break;
default:
chunkDataStream.CopyTo(outputStream);
break;
}
outputStream.Seek(0, SeekOrigin.Begin);
return(outputStream);
}
private IEnumerable <Column> GetColumns()
{
using (var stream = File.OpenRead(_reqionFilePath))
{
var offsets = new List <int>();
var timestamps = new List <int>();
using (var reader = new BinaryReader(stream))
{
for (int i = 0; i < SECTOR_INTS; i++)
{
int offset = reader.ReadInt32BE();
offsets.Add(offset);
}
for (int i = 0; i < SECTOR_INTS; i++)
{
int timestamp = reader.ReadInt32BE();
timestamps.Add(timestamp);
}
for (int i = 0; i < offsets.Count; i++)
{
if (offsets[i] == 0)
{
continue;
}
int sectorNumber = offsets[i] >> 8;
int numSectors = offsets[i] & 0xFF;
if (numSectors == 0)
{
continue;
}
stream.Seek(sectorNumber * SECTOR_BYTES, SeekOrigin.Begin);
int length = reader.ReadInt32BE();
ChunkFormat format = (ChunkFormat)reader.ReadByte();
var data = reader.ReadBytes(length - 1);
Column column = null;
try
{
column = new Column(format,
new MemoryStream(data),
UnixDateTimeHelpers.ToDateTime(timestamps[i]));
}
catch (InvalidDataException)
{
//Ignore
}
if (column != null)
{
yield return(column);
}
}
}
}
}
