/// <summary>
/// Downloads a specific file from the Steam servers to the specified Stream.
/// </summary>
/// <param name="file">The file to download, given from the manifest.</param>
/// <param name="downloadStream">The stream to which file data should be written.</param>
/// <param name="priority">The download priority.</param>
/// <param name="cryptKey">The AES encryption key used for any encrypted files.</param>
/// <returns>A byte array representing the file.</returns>
public void DownloadFileToStream(Steam2Manifest.Node file, Stream downloadStream, DownloadPriority priority = DownloadPriority.Low, byte[] cryptKey = null)
{
if ((file.Attributes & Steam2Manifest.Node.Attribs.EncryptedFile) != 0 && cryptKey == null)
{
throw new Steam2Exception(string.Format("AES encryption key required for file: {0}", file.FullName));
}
const uint MaxParts = 16;
uint numFileparts = (uint)Math.Ceiling((float)file.SizeOrCount / (float)file.Parent.BlockSize);
uint numChunks = (uint)Math.Ceiling((float)numFileparts / (float)MaxParts);
for (uint x = 0; x < numChunks; ++x)
{
byte[] filePart = DownloadFileParts(file, x * MaxParts, MaxParts, priority, cryptKey);
downloadStream.Write(filePart, 0, filePart.Length);
}
}
byte[] DownloadFileParts(Steam2Manifest.Node file, uint filePart, uint numParts, DownloadPriority priority = DownloadPriority.Low, byte[] cryptKey = null)
{
this.SendCommand(
7, // download file
this.StorageID,
this.MessageID,
file.FileID,
filePart,
numParts,
( byte )priority
);
uint storId = NetHelpers.EndianSwap(this.Socket.Reader.ReadUInt32());
uint msgId = NetHelpers.EndianSwap(this.Socket.Reader.ReadUInt32());
byte hasFile = this.Socket.Reader.ReadByte();
uint numChunks = NetHelpers.EndianSwap(this.Socket.Reader.ReadUInt32());
uint fileModeValue = NetHelpers.EndianSwap(this.Socket.Reader.ReadUInt32());
FileMode fileMode = ( FileMode )fileModeValue;
MemoryStream ms = new MemoryStream();
for (int x = 0; x < numChunks; ++x)
{
uint storId2 = NetHelpers.EndianSwap(this.Socket.Reader.ReadUInt32());
uint msgId2 = NetHelpers.EndianSwap(this.Socket.Reader.ReadUInt32());
uint chunkLen = NetHelpers.EndianSwap(this.Socket.Reader.ReadUInt32());
uint storId3 = NetHelpers.EndianSwap(this.Socket.Reader.ReadUInt32());
uint msgId3 = NetHelpers.EndianSwap(this.Socket.Reader.ReadUInt32());
uint chunkLen2 = NetHelpers.EndianSwap(this.Socket.Reader.ReadUInt32());
if (chunkLen == 0)
{
continue;
}
byte[] chunk = null;
int len = 0;
if (fileMode == FileMode.Compressed)
{
chunk = this.Socket.Reader.ReadBytes(( int )chunkLen);
len = DecompressFileChunk(ref chunk, ( int )file.Parent.BlockSize);
}
else if (fileMode == FileMode.Encrypted)
{
len = DecryptFileChunk(out chunk, ( int )chunkLen, cryptKey);
}
else if (fileMode == FileMode.EncryptedAndCompressed)
{
// Account for 2 integers before the encrypted data
chunkLen -= 8;
// Skip first integer (length of the encrypted data)
this.Socket.Reader.ReadInt32();
// Length of decrypted and decompressed data
int plainLen = this.Socket.Reader.ReadInt32();
DecryptFileChunk(out chunk, ( int )chunkLen, cryptKey);
len = DecompressFileChunk(ref chunk, plainLen);
}
else if (fileMode == FileMode.None)
{
chunk = this.Socket.Reader.ReadBytes(( int )chunkLen);
len = chunk.Length;
}
ms.Write(chunk, 0, len);
}
byte[] data = ms.ToArray();
this.MessageID++;
return(data);
}
