/* define our own since we want to use private bool[] for c[] bits */
internal new eCorrectionResult Deconvolution()
{
int failures = ConvolutionalCoder.Decode(SCHData, ref SCHDataDecoded);
if (failures == 0)
{
return(eCorrectionResult.Correct);
}
else if (failures < 10)
{
return(eCorrectionResult.Fixed);
}
else
{
return(eCorrectionResult.Failed);
}
}
/* define our own since we want to use private bool[] for c[] bits */
internal new eCorrectionResult Deconvolution(bool[] burstBufferC)
{
int failures = ConvolutionalCoder.Decode(burstBufferC, ref BurstBufferU);
if (failures == 0)
{
return(eCorrectionResult.Correct);
}
else if (failures < 10)
{
return(eCorrectionResult.Fixed);
}
else
{
return(eCorrectionResult.Failed);
}
}
public override eSuccessState ParseData(GSMParameters param, bool[] decodedBurst, int sequence)
{
eSuccessState success = eSuccessState.Unknown;
if (IsDummy(decodedBurst))
{
State = eBurstState.Idle;
DummyBursts++;
//CloseFiles();
/* don't treat TCHs as a reliable source for end-of-connection detection */
//DummyBurstReceived(param);
if (DumpRawData)
{
StatusMessage = "Dummy Burst";
}
return(eSuccessState.Succeeded);
}
EncryptionType = AssociatedSACCH.EncryptionType;
ChannelEncrypted = AssociatedSACCH.ChannelEncrypted;
StoreBurstContext(param, decodedBurst, TCHSeq);
/* GSM 05.03 Ch 2.1 */
/* when we got 8 TCH bursts */
if (++TCHSeq == 8)
{
TCHSeq = 0;
/* try to decrypt buffer if this is enabled, but do not try to crack the key */
if (!HandleEncryption(param, false))
{
State = eBurstState.CryptedTraffic;
/* encrypted but no decryptor available, silently return */
return(eSuccessState.Unknown);
}
/* deinterleave the 8 TCH bursts. the result is a 456 bit block. i[] to c[] */
Deinterleave();
/*
* GSM-05.03 4.2.5
* was this burst stolen for a FACCH? hl(B) (in e[]) is set for the last 4 bursts */
if (IsHL(decodedBurst))
{
/* pass encryption information to FACCH */
FACCH.A5Algorithm = A5Algorithm;
FACCH.A5CipherKey = A5CipherKey;
FACCH.ChannelEncrypted = ChannelEncrypted;
/* pass c[] to FACCH handler */
success = FACCH.ParseFACCHData(param, BurstBufferC);
StatusMessage = FACCH.StatusMessage;
ErrorMessage = FACCH.ErrorMessage;
FACCH.StatusMessage = null;
FACCH.ErrorMessage = null;
}
else
{
/* TCH speech/data (data not supported yet) */
/* split up the class 1... */
Array.Copy(BurstBufferC, Class1DataConv, Class1DataConv.Length);
/* ... and class 2 bits */
Array.Copy(BurstBufferC, 378, GSMFrameBufferD, 182, 78);
/* use an own convolutional coder buffer for these 188 bits */
if (ConvolutionalCoder.Decode(Class1DataConv, ref Class1Data) == 0)
{
bool[] parityBits = new bool[53];
for (int pos = 0; pos < 91; pos++)
{
GSMFrameBufferD[2 * pos] = Class1Data[pos];
GSMFrameBufferD[2 * pos + 1] = Class1Data[184 - pos];
}
/* calculate parity */
Array.Copy(GSMFrameBufferD, 0, parityBits, 0, 50);
Array.Copy(Class1Data, 91, parityBits, 50, 3);
bool[] crc = CRC.Calc(parityBits, 0, 53, CRC.PolynomialTCHFR);
if (CRC.Matches(crc))
{
DataBursts++;
success = eSuccessState.Succeeded;
if (ChannelEncrypted)
{
State = eBurstState.DecryptedTraffic;
}
else
{
State = eBurstState.PlainTraffic;
}
#if false
#region Microsoft WAV49 GSM Format
if (WAV49First)
{
BitMapping.Unmap(GSMFrameBufferD, 0, WAV49FrameBool, 0, BitMapping.g610BitOrder);
}
else
{
/* directly unmap into boolean WAV49 frame buffer */
BitMapping.Unmap(GSMFrameBufferD, 0, WAV49FrameBool, 260, BitMapping.g610BitOrder);
/* convert that WAV49 frame to byte[] */
ByteUtil.BitsToBytes(WAV49FrameBool, WAV49FrameByte);
try
{
if (OutFile == null)
{
string name = ("GSM_" + Name + "_" + param.FN + ".wav").Replace("/", "_");
OutFile = new FileStream(name, FileMode.Create, FileAccess.ReadWrite, FileShare.ReadWrite);
WriteHeader(OutFile);
}
/* and write it */
WriteBuffer(OutFile, WAV49FrameByte);
WriteHeader(OutFile);
StatusMessage = "GSM 06.10 Voice data (" + OutFile.Name + ")";
}
catch (Exception e)
{
StatusMessage = "GSM 06.10 Voice data (Writing file failed, " + e.GetType() + ")";
}
}
WAV49First = !WAV49First;
#endregion
#endif
if (ChannelMode != 33)
{
#region write audio dump in RTP A/V Format
/* GSM frame magic */
RTPFrameBool[0] = true;
RTPFrameBool[1] = true;
RTPFrameBool[2] = false;
RTPFrameBool[3] = true;
/* directly unmap into boolean RTP frame buffer */
BitMapping.Unmap(GSMFrameBufferD, 0, RTPFrameBool, 4, BitMapping.g610BitOrder);
/* convert that RTP frame to byte[] */
ByteUtil.BitsToBytes(RTPFrameBool, RTPFrameByte);
StatusMessage = "";
if (ChannelEncrypted)
{
StatusMessage += "======= encrypted =======" + Environment.NewLine;
}
try
{
if (OutFile == null)
{
string name = ("GSM_" + Name + "_" + param.FN).Replace("/", "_");
OutFile = new FileStream(name + ".gsm", FileMode.Create, FileAccess.ReadWrite, FileShare.ReadWrite);
//OutFileRaw = new FileStream(name + ".raw", FileMode.Create, FileAccess.ReadWrite, FileShare.ReadWrite);
StatusMessage += "Created file: '" + name + "'" + Environment.NewLine;
}
/* and write it */
OutFile.Write(RTPFrameByte, 0, RTPFrameByte.Length);
OutFile.Flush();
/*
* Array.Copy(GSMFrameBufferD, 0, RTPFrameBool, 4, GSMFrameBufferD.Length);
* RTPFrameBool[0] = false;
* RTPFrameBool[1] = false;
* RTPFrameBool[2] = false;
* RTPFrameBool[3] = false;
* ByteUtil.BitsToBytes(RTPFrameBool, RTPFrameByte);
* OutFileRaw.Write(RTPFrameByte, 0, RTPFrameByte.Length);
*/
StatusMessage += "GSM 06.10 Voice data (" + OutFile.Name + ")";
}
catch (Exception e)
{
StatusMessage += "GSM 06.10 Voice data (Writing file failed, " + e.GetType() + ")";
}
#endregion
}
else
{
#region write audio dump in AMR Format (assume 12.2kbit/s)
UnmapDToW();
UnmapWToS();
/* convert that AMR frame to byte[] */
ByteUtil.BitsToBytes(BurstBufferSpeechBits, RTPFrameByte);
StatusMessage = "";
if (ChannelEncrypted)
{
StatusMessage += "======= encrypted =======" + Environment.NewLine;
}
try
{
if (OutFile == null)
{
byte[] fileHeader = new byte[] { 0x23, 0x21, 0x41, 0x4D, 0x52, 0x0A };
string name = ("GSM_" + Name + "_" + param.FN).Replace("/", "_");
OutFile = new FileStream(name + ".amr", FileMode.Create, FileAccess.ReadWrite, FileShare.ReadWrite);
OutFile.Write(fileHeader, 0, fileHeader.Length);
}
/* and write it */
OutFile.WriteByte(0x3C);
OutFile.Write(RTPFrameByte, 0, 31);
OutFile.Flush();
StatusMessage += "GSM 06.90 Voice data (" + OutFile.Name + ")";
}
catch (Exception e)
{
StatusMessage += "GSM 06.90 Voice data (Writing file failed, " + e.GetType() + ")";
}
#endregion
}
}
else
{
State = eBurstState.Failed;
CryptedFrames++;
ErrorMessage = "(TCH/F Class Ia: CRC Error)";
}
}
else
{
State = eBurstState.Failed;
CryptedFrames++;
ErrorMessage = "(TCH/F Class I: Error in ConvolutionalCoder)";
}
}
/* trick:
* first use the last 8 bursts until one block was successfully decoded.
* then use the last 4 bursts as we normally would do.
* this will help in finding the correct alignment within the 4 frames.
*/
if (success == eSuccessState.Succeeded)
{
BurstShiftCount = 4;
}
else
{
BurstShiftCount = 7;
}
/* save the last n bursts for the next block */
for (int pos = 0; pos < BurstShiftCount; pos++)
{
BurstData src = BurstBlock[(8 - BurstShiftCount) + pos];
BurstData dst = BurstBlock[pos];
dst.FN = src.FN;
dst.Count = src.Count;
Array.Copy(src.BurstBufferI, 0, dst.BurstBufferI, 0, dst.BurstBufferI.Length);
Array.Copy(src.BurstBufferE, 0, dst.BurstBufferE, 0, dst.BurstBufferE.Length);
}
/* and continue at position n (so we will read another 8-n bursts) */
TCHSeq = BurstShiftCount;
/* only when in sync, return error flag */
if (BurstShiftCount == 4)
{
return(success);
}
}
return(eSuccessState.Unknown);
}
