/// <summary>
/// Creates "request" or "cancel" messages
/// </summary>
/// <param name="index">Zero-based piece index</param>
/// <param name="begin">Zero-based offset within the piece</param>
/// <param name="length">Specifies the requested (cancelled) block's length</param>
public PeerMessage(PeerMessageType type, int index, int begin, int length)
{
if (!(type == PeerMessageType.request || type == PeerMessageType.cancel))
{
throw new ArgumentException("Type of the message must be \"request\" or \"cancel\"");
}
messageType = type;
msgContents = new byte[msgLenSpace + msgTypeSpace + msgIntSpace * 3];
Array.Copy(PeerConnection.HTONNTOH(BitConverter.GetBytes(13)), msgContents, msgLenSpace);
msgContents[msgLenSpace] = (byte)messageType;
Array.Copy(PeerConnection.HTONNTOH(BitConverter.GetBytes(index)), 0, msgContents, msgLenSpace + msgTypeSpace, msgIntSpace);
Array.Copy(PeerConnection.HTONNTOH(BitConverter.GetBytes(begin)), 0, msgContents, msgLenSpace + msgTypeSpace + msgIntSpace, msgIntSpace);
Array.Copy(PeerConnection.HTONNTOH(BitConverter.GetBytes(length)), 0, msgContents, msgLenSpace + msgTypeSpace + msgIntSpace * 2, msgIntSpace);
this.pieceIndex = index;
this.pieceOffset = begin;
this.length = length;
}
/// <summary>
/// Creates a message with no payload (keep-alive, choke, unchoke, interested or not interested)
/// </summary>
/// <param name="type">Type of the message</param>
/// <exception cref="ArgumentException">Thrown if passed message type must have a payload</exception>
public PeerMessage(PeerMessageType type)
{
if (type == PeerMessageType.keepAlive)
{
msgContents = new byte[msgLenSpace];
}
else if (type == PeerMessageType.choke || type == PeerMessageType.unchoke || type == PeerMessageType.interested ||
type == PeerMessageType.notInterested)
{
msgContents = new byte[msgLenSpace + msgTypeSpace];
Array.Copy(PeerConnection.HTONNTOH(BitConverter.GetBytes(1)), msgContents, msgLenSpace);
msgContents[msgLenSpace] = (byte)type;
}
else
{
throw new ArgumentException($"This message type: {type.ToString()} must have non-empty payload");
}
}