/// <summary> Saves this NBT file to a stream. Nothing is written to stream if RootTag is <c>null</c>. </summary>
/// <param name="stream"> Stream to write data to. May not be <c>null</c>. </param>
/// <param name="compression"> Compression mode to use for saving. May not be AutoDetect. </param>
/// <returns> Number of bytes written to the stream. </returns>
/// <exception cref="ArgumentNullException"> <paramref name="stream"/> is <c>null</c>. </exception>
/// <exception cref="ArgumentException"> If AutoDetect was given as the <paramref name="compression"/> mode. </exception>
/// <exception cref="ArgumentOutOfRangeException"> If an unrecognized/unsupported value was given for <paramref name="compression"/>. </exception>
/// <exception cref="InvalidDataException"> If given stream does not support writing. </exception>
/// <exception cref="NbtFormatException"> If RootTag is null;
/// or if RootTag is unnamed;
/// or if one of the NbtCompound tags contained unnamed tags;
/// or if an NbtList tag had Unknown list type and no elements. </exception>
public long SaveToStream([NotNull] Stream stream, NbtCompression compression)
{
if (stream == null)
{
throw new ArgumentNullException("stream");
}
switch (compression)
{
case NbtCompression.AutoDetect:
throw new ArgumentException("AutoDetect is not a valid NbtCompression value for saving.");
case NbtCompression.ZLib:
case NbtCompression.GZip:
case NbtCompression.None:
break;
default:
throw new ArgumentOutOfRangeException("compression");
}
if (rootTag.Name == null)
{
// This may trigger if root tag has been renamed
throw new NbtFormatException(
"Cannot save NbtFile: Root tag is not named. Its name may be an empty string, but not null.");
}
long startOffset = 0;
if (stream.CanSeek)
{
startOffset = stream.Position;
}
else
{
stream = new ByteCountingStream(stream);
}
switch (compression)
{
case NbtCompression.ZLib:
stream.WriteByte(0x78);
stream.WriteByte(0x01);
int checksum;
using (var compressStream = new ZLibStream(stream, CompressionMode.Compress, true))
{
var bufferedStream = new BufferedStream(compressStream, WriteBufferSize);
RootTag.WriteTag(new NbtBinaryWriter(bufferedStream, BigEndian));
bufferedStream.Flush();
checksum = compressStream.Checksum;
}
byte[] checksumBytes = BitConverter.GetBytes(checksum);
if (BitConverter.IsLittleEndian)
{
// Adler32 checksum is big-endian
Array.Reverse(checksumBytes);
}
stream.Write(checksumBytes, 0, checksumBytes.Length);
break;
case NbtCompression.GZip:
using (var compressStream = new GZipStream(stream, CompressionMode.Compress, true))
{
// use a buffered stream to avoid GZipping in small increments (which has a lot of overhead)
var bufferedStream = new BufferedStream(compressStream, WriteBufferSize);
RootTag.WriteTag(new NbtBinaryWriter(bufferedStream, BigEndian));
bufferedStream.Flush();
}
break;
case NbtCompression.None:
var writer = new NbtBinaryWriter(stream, BigEndian);
RootTag.WriteTag(writer);
break;
default:
throw new ArgumentOutOfRangeException("compression");
}
if (stream.CanSeek)
{
return(stream.Position - startOffset);
}
else
{
return(((ByteCountingStream)stream).BytesWritten);
}
}
/// <summary> Loads NBT data from a stream. Existing <c>RootTag</c> will be replaced </summary>
/// <param name="stream"> Stream from which data will be loaded. If compression is set to AutoDetect, this stream must support seeking. </param>
/// <param name="compression"> Compression method to use for loading/saving this file. </param>
/// <param name="selector"> Optional callback to select which tags to load into memory. Root may not be skipped.
/// No reference is stored to this callback after loading (don't worry about implicitly captured closures). May be <c>null</c>. </param>
/// <returns> Number of bytes read from the stream. </returns>
/// <exception cref="ArgumentNullException"> <paramref name="stream"/> is <c>null</c>. </exception>
/// <exception cref="ArgumentOutOfRangeException"> If an unrecognized/unsupported value was given for <paramref name="compression"/>. </exception>
/// <exception cref="NotSupportedException"> If <paramref name="compression"/> is set to AutoDetect, but the stream is not seekable. </exception>
/// <exception cref="EndOfStreamException"> If file ended earlier than expected. </exception>
/// <exception cref="InvalidDataException"> If file compression could not be detected, decompressing failed, or given stream does not support reading. </exception>
/// <exception cref="NbtFormatException"> If an error occurred while parsing data in NBT format. </exception>
public long LoadFromStream([NotNull] Stream stream, NbtCompression compression, [CanBeNull] TagSelector selector)
{
if (stream == null)
{
throw new ArgumentNullException("stream");
}
FileName = null;
// detect compression, based on the first byte
if (compression == NbtCompression.AutoDetect)
{
FileCompression = DetectCompression(stream);
}
else
{
FileCompression = compression;
}
// prepare to count bytes read
long startOffset = 0;
if (stream.CanSeek)
{
startOffset = stream.Position;
}
else
{
stream = new ByteCountingStream(stream);
}
switch (FileCompression)
{
case NbtCompression.GZip:
using (var decStream = new GZipStream(stream, CompressionMode.Decompress, true))
{
if (bufferSize > 0)
{
LoadFromStreamInternal(new BufferedStream(decStream, bufferSize), selector);
}
else
{
LoadFromStreamInternal(decStream, selector);
}
}
break;
case NbtCompression.None:
LoadFromStreamInternal(stream, selector);
break;
case NbtCompression.ZLib:
if (stream.ReadByte() != 0x78)
{
throw new InvalidDataException(WrongZLibHeaderMessage);
}
stream.ReadByte();
using (var decStream = new DeflateStream(stream, CompressionMode.Decompress, true))
{
if (bufferSize > 0)
{
LoadFromStreamInternal(new BufferedStream(decStream, bufferSize), selector);
}
else
{
LoadFromStreamInternal(decStream, selector);
}
}
break;
default:
throw new ArgumentOutOfRangeException("compression");
}
// report bytes read
if (stream.CanSeek)
{
return(stream.Position - startOffset);
}
else
{
return(((ByteCountingStream)stream).BytesRead);
}
}
