/// <summary>
/// Parses the bytes from the given <paramref name="inputStream"/> depending on the provided
/// <paramref name="mode"/> and returns the API packet.
/// </summary>
/// <remarks>The operating mode must be <see cref="OperatingMode.API"/> or
/// <see cref="OperatingMode.API_ESCAPE"/>.</remarks>
/// <param name="inputStream">Input stream to read bytes from.</param>
/// <param name="mode">XBee device operating mode.</param>
/// <returns>Parsed packet from the input stream.</returns>
/// <exception cref="ArgumentException">If <paramref name="mode"/> is invalid
/// or if the <paramref name="inputStream"/> cannot be read.</exception>
/// <exception cref="ArgumentNullException">If <paramref name="inputStream"/> is <c>null</c>.</exception>
/// <exception cref="InvalidPacketException">If there is not enough data in the stream or if there
/// is an error verifying the checksum or if the payload is invalid for the specified frame type.</exception>
public XBeePacket ParsePacket(Stream inputStream, OperatingMode mode)
{
if (inputStream == null)
{
throw new ArgumentNullException("Input stream cannot be null.");
}
if (!inputStream.CanRead)
{
throw new ArgumentException("Could not read from the input stream.");
}
if (mode != OperatingMode.API && mode != OperatingMode.API_ESCAPE)
{
throw new ArgumentException("Operating mode must be API or API Escaped.");
}
try
{
// Read packet size.
int hSize = ReadByte(inputStream, mode);
int lSize = ReadByte(inputStream, mode);
int Length = hSize << 8 | lSize;
// Read the payload.
byte[] payload = ReadBytes(inputStream, mode, Length);
// Calculate the expected checksum.
XBeeChecksum checksum = new XBeeChecksum();
checksum.Add(payload);
byte expectedChecksum = (byte)(checksum.Generate() & 0xFF);
// Read checksum from the input stream.
byte readChecksum = (byte)(ReadByte(inputStream, mode) & 0xFF);
// Verify the checksum of the read bytes.
if (readChecksum != expectedChecksum)
{
throw new InvalidPacketException("Invalid checksum (expected 0x"
+ HexUtils.ByteToHexString(expectedChecksum) + ").");
}
return(ParsePayload(payload));
}
catch (IOException e)
{
throw new InvalidPacketException("Error parsing packet: " + e.Message, e);
}
}
/// <summary>
/// Class constructor. Instantiates a new <see cref="XBeePacket"/> object.
/// </summary>
protected XBeePacket()
{
checksum = new XBeeChecksum();
}