/// <summary>
/// Build or continue building the message. Returns true if the resulted message is valid and ready to be parsed
/// </summary>
public bool Build(BigEndianReader reader)
{
if (IsValid)
return true;
if (reader.BytesAvailable >= 2 && !Header.HasValue)
{
Header = reader.ReadShort();
}
if (LengthBytesCount.HasValue &&
reader.BytesAvailable >= LengthBytesCount && !Length.HasValue)
{
if (LengthBytesCount < 0 || LengthBytesCount > 3)
throw new Exception("Malformated Message Header, invalid bytes number to read message length (inferior to 0 or superior to 3)");
Length = 0;
// 3..0 or 2..0 or 1..0
for (int i = LengthBytesCount.Value - 1; i >= 0; i--)
{
Length |= reader.ReadByte() << (i * 8);
}
}
// first case : no data read
if (Data == null && Length.HasValue)
{
if (Length == 0)
Data = new byte[0];
// enough bytes in the buffer to build a complete message
if (reader.BytesAvailable >= Length)
{
Data = reader.ReadBytes(Length.Value);
}
// not enough bytes, so we read what we can
else if (Length > reader.BytesAvailable)
{
Data = reader.ReadBytes((int) reader.BytesAvailable);
}
}
//second case : the message was split and it missed some bytes
if (Data != null && Length.HasValue && Data.Length < Length)
{
int bytesToRead = 0;
// still miss some bytes ...
if (Data.Length + reader.BytesAvailable < Length)
bytesToRead = (int)reader.BytesAvailable;
// there is enough bytes in the buffer to complete the message :)
else if(Data.Length + reader.BytesAvailable >= Length)
bytesToRead = Length.Value - Data.Length;
if(bytesToRead != 0)
{
int oldLength = Data.Length;
Array.Resize(ref m_data, (int)( Data.Length + bytesToRead ));
Array.Copy(reader.ReadBytes(bytesToRead), 0, Data, oldLength, bytesToRead);
}
}
return IsValid;
}
