/////////////////////////////////////////////////////////////////////////////
// Check is received packet's checksum corrent.
/////////////////////////////////////////////////////////////////////////////
bool IsReplyChecksumOK(byte[] data, int index, int crcSize)
{
object crc = null;
if (this.m_ChecksumSettings.Type == ChecksumType.Own)
{
this.Checksum = null;
GXChecksumEventArgs e = new GXChecksumEventArgs(this);
NotifyCountChecksum(e);
crc = e.Checksum;
}
else
{
crc = CountChecksum(this.m_ChecksumSettings.Start, this.m_ChecksumSettings.Count);
}
byte[] chksumCount = GXConverter.GetBytes(crc, ShouldSwap());
byte[] chksumRead = new byte[crcSize];
Array.Copy(data, index, chksumRead, 0, crcSize);
if (Gurux.Common.GXCommon.IndexOf(chksumCount, chksumRead, 0, crcSize) != 0)
{
if (this.Sender != null && this.Sender.Trace >= System.Diagnostics.TraceLevel.Error)
{
Gurux.Common.GXCommon.TraceWriteLine("GXPacket -- Checksum count failed. CRCs are not same + " + BitConverter.ToString(chksumCount).Replace('-', ' ') + " / " + BitConverter.ToString(chksumRead).Replace('-', ' '));
}
this.Checksum = null;
m_DataAdded = true;
return false;
}
this.Checksum = crc;
return true;
}
/// <summary>
/// Computes the checksum for the contents of the packet.
/// </summary>
/// <remarks>
/// The checksum is computed from the data of the GXPacket object. This method should not be called directly.
/// GXClient calls this method automatically, when checksum is computed.
/// </remarks>
/// <param name="start">Position where to start counting CRC.</param>
/// <param name="count">How many bytes are counted. If all, set to -1.</param>
/// <returns>Counted checksum.</returns>
public object CountChecksum(int start, int count)
{
this.m_Checksum = null;
if (this.ChecksumSettings.Type == ChecksumType.Own)
{
GXChecksumEventArgs e = new GXChecksumEventArgs(this);
NotifyCountChecksum(e);
return e.Checksum;
}
byte[] data = ExtractPacket(true);
if (count < 0)
{
count = data.Length + count + 1 - start;
}
object crc = null;
if (this.ChecksumSettings.Type == ChecksumType.Adler32)
{
crc = CRCCTemplate.CountAdler32Checksum(data, start, count);
}
else if (this.ChecksumSettings.Type == ChecksumType.Sum8Bit)
{
int val = 0;
for (int pos = 0; pos != count; ++pos)
{
val = (val + data[start + pos]) & 0xFF;
}
crc = (byte)val;
}
else if (this.ChecksumSettings.Type == ChecksumType.Sum16Bit)
{
int val = 0;
for (int pos = 0; pos != count; ++pos)
{
val = (val + data[start + pos]) & 0xFF;
}
crc = (UInt16)val;
}
else if (this.ChecksumSettings.Type == ChecksumType.Sum32Bit)
{
UInt32 val = 0;
for (int pos = 0; pos != count; ++pos)
{
val = (val + data[start + pos]) & 0xFF;
}
crc = (UInt32)val;
}
else
{
if (m_crc == null || this.ChecksumSettings.Dirty)
{
if (this.ChecksumSettings.Size != 8 && this.ChecksumSettings.Size != 16 && this.ChecksumSettings.Size != 24 && this.ChecksumSettings.Size != 32)
{
throw new Exception(Resources.ChecksumSizeIsInvalid);
}
m_crc = new CRCCTemplate(this.ChecksumSettings.Size, this.ChecksumSettings.Polynomial, this.ChecksumSettings.InitialValue, this.ChecksumSettings.FinalXOR, this.ChecksumSettings.ReverseData, this.ChecksumSettings.Reflection);
this.ChecksumSettings.Dirty = false;
}
crc = m_crc.CountCRC(data, start, count);
if (this.ShouldSwap() || this.ChecksumSettings.ReversedChecksum)
{
if (crc is UInt16)
{
crc = CRCCTemplate.Swap((UInt16)crc);
}
else if (crc is UInt32)
{
crc = CRCCTemplate.Swap((UInt32)crc);
}
}
}
return crc;
}
internal void NotifyCountChecksum(GXChecksumEventArgs e)
{
if (OnCountChecksum != null)
{
OnCountChecksum(this, e);
}
//GXCom server is asking packet to count checksum. Packet asks client to count it.
else if (Sender != null)
{
Sender.NotifyCountChecksum(e);
}
}
internal void NotifyCountChecksum(GXChecksumEventArgs e)
{
if (PacketParser != null)
{
PacketParser.CountChecksum(this, e);
}
else if (OnCountChecksum != null)
{
OnCountChecksum(this, e);
}
}
public void CountChecksum(object sender, GXChecksumEventArgs e)
{
}
void IGXPacketParser.CountChecksum(object sender, GXChecksumEventArgs e)
{
throw new NotImplementedException();
}