public OTRMessage ExtractMessage(byte[] in_message_byte_array)
{
int _next_index = 0;
_otr_message = null;
_temp_buffer = null;
_message_type = OTR_MESSAGE_TYPE.INVALID;
//get protocol version
_next_index = Utility.DecodeShortFromBytes(in_message_byte_array, _next_index, ref _temp_buffer_2);
OTR_VERSION _otr_version = Utility.GetOTRVersion(_temp_buffer_2);
if (_otr_version == OTR_VERSION.INVALID)
throw new ArgumentException("ExtractMessage:OTR version is invalid");
_otr_message = new OTRMessage();
_otr_message.SetProtocolVersion(_otr_version);
// get message type
_temp_buffer_2 = _temp_buffer = null;
_next_index = Utility.DecodeByteFromBytes(in_message_byte_array, _next_index, ref _temp_buffer_2);
_message_type = GetMessageType(_temp_buffer_2[0]);
if (_message_type == OTR_MESSAGE_TYPE.INVALID)
throw new ArgumentException("ExtractMessage:OTR message type is invalid");
_otr_message.SetMessageType(_message_type);
//get instance tags
if (_otr_version != OTR_VERSION.VERSION_2)
{
_temp_buffer_2 = _temp_buffer = null;
_next_index = Utility.DecodeIntFromBytes(in_message_byte_array, _next_index, ref _temp_buffer_2);
_otr_message.SetSenderInstanceTag(_temp_buffer_2);
if (_otr_message.GetSenderInstanceTag() < 4)
throw new ArgumentException("ExtractMessage:The Sender's instance tag cannot be less than 4");
if (_buddy_instance_tag == 0)
_buddy_instance_tag = _otr_message.GetSenderInstanceTag();
if (_buddy_instance_tag != 0 && _otr_message.GetSenderInstanceTag() != _buddy_instance_tag)
throw new ArgumentException("ExtractMessage:The Sender's instance tag is invalid");
_temp_buffer_2 = _temp_buffer = null;
_next_index = Utility.DecodeIntFromBytes(in_message_byte_array, _next_index, ref _temp_buffer_2);
_otr_message.SetReceiverInstanceTag(_temp_buffer_2);
}
if (_message_type == OTR_MESSAGE_TYPE.DATA)
return ExtractData(in_message_byte_array, _next_index);
else if (_message_type == OTR_MESSAGE_TYPE.DH_COMMIT)
return ExtractDHCommit(in_message_byte_array, _next_index);
else if (_message_type == OTR_MESSAGE_TYPE.DH_KEY)
return ExtractDHKey(in_message_byte_array, _next_index);
else if (_message_type == OTR_MESSAGE_TYPE.REVEAL_SIGNATURE)
return ExtractRevealSig(in_message_byte_array, _next_index);
else if (_message_type == OTR_MESSAGE_TYPE.SIGNATURE)
return ExtractSignature(in_message_byte_array, _next_index);
return null;
}
