public static void ChangeDemoDir(SourceDemo demo, Stream s, string newDir)
{
void Write(byte[] buf) => s.Write(buf, 0, buf.Length);
string old = demo.Header.GameDirectory;
if (old == newDir)
{
// no difference
Write(demo.Reader.Data);
return;
}
int lenDiff = newDir.Length - old.Length;
BitStreamReader bsr = demo.Reader;
byte[] dirBytes = Encoding.ASCII.GetBytes(newDir);
Write(bsr.ReadBytes(796));
Write(dirBytes); // header doesn't matter but I change it anyway
Write(new byte[260 - newDir.Length]);
bsr.SkipBytes(260);
Write(bsr.ReadBytes(12));
byte[] tmp = BitConverter.GetBytes((uint)(bsr.ReadUInt() + lenDiff));
if (!BitConverter.IsLittleEndian)
{
tmp = tmp.Reverse().ToArray();
}
Write(tmp);
foreach (SignOn signOn in demo.FilterForPacket <SignOn>().Where(signOn => signOn.FilterForMessage <SvcServerInfo>().Any()))
{
// catch up to signOn packet
int byteCount = (signOn.Reader.AbsoluteBitIndex - bsr.AbsoluteBitIndex) / 8;
Write(bsr.ReadBytes(byteCount));
bsr.SkipBits(signOn.Reader.BitLength);
BitStreamWriter bsw = new BitStreamWriter();
BitStreamReader signOnReader = signOn.Reader;
bsw.WriteBits(signOnReader.ReadRemainingBits());
signOnReader = signOnReader.FromBeginning();
int bytesToMessageStreamSize = demo.DemoInfo.MaxSplitscreenPlayers * 76 + 8;
signOnReader.SkipBytes(bytesToMessageStreamSize);
// edit the message stream length - read uint, and edit at index before the reading of said uint
bsw.EditIntAtIndex((int)(signOnReader.ReadUInt() + lenDiff), signOnReader.CurrentBitIndex - 32, 32);
// actually change the game dir
SvcServerInfo serverInfo = signOn.FilterForMessage <SvcServerInfo>().Single();
int editIndex = serverInfo.GameDirBitIndex - signOn.Reader.AbsoluteBitIndex;
bsw.RemoveBitsAtIndex(editIndex, old.Length * 8);
bsw.InsertBitsAtIndex(dirBytes, editIndex, newDir.Length * 8);
Write(bsw.AsArray);
}
Write(bsr.ReadRemainingBits().bytes);
}