// For use with System.IO.Pipelines
// Decrypt packets directly from underlying data stream without needing to buffer
public int TryDecrypt(ReadOnlySequence <byte> buffer, out PoolPacketReader packet)
{
if (buffer.Length < HEADER_SIZE)
{
packet = null;
return(0);
}
SequenceReader <byte> reader = new(buffer);
reader.TryReadLittleEndian(out short encSeq);
reader.TryReadLittleEndian(out int packetSize);
int rawPacketSize = HEADER_SIZE + packetSize;
if (buffer.Length < rawPacketSize)
{
packet = null;
return(0);
}
// Only decode sequence once we know there is sufficient data because it mutates IV
short decSeq = DecodeSeqBase(encSeq);
if (decSeq != Cipher.Version)
{
throw new ArgumentException($"Packet has invalid sequence header: {decSeq}");
}
byte[] data = ArrayProvider.Rent(packetSize);
buffer.Slice(HEADER_SIZE, packetSize).CopyTo(data);
foreach (ICrypter crypter in DecryptSeq)
{
crypter.Decrypt(data, 0, packetSize);
}
packet = new(ArrayProvider, data, packetSize);
return(rawPacketSize);
}