/// <summary>
/// Reads the FIT binary file header and crc to check compatibility and integrity.
/// Also checks data reords size.
/// Returns true if file is ok (not corrupt).
///</summary>
/// <param name="fitStream">Seekable (file)stream to parse.</param>
public bool CheckIntegrity(Stream fitStream)
{
bool isValid;
try
{
// Is there a valid header?
Header header = new Header(fitStream);
isValid = header.IsValid();
// Are there as many data bytes as the header claims?
isValid &= ((header.Size + header.DataSize + 2) == fitStream.Length);
// Is the file CRC ok?
byte[] data = new byte[fitStream.Length];
fitStream.Position = 0;
fitStream.Read(data, 0, data.Length);
isValid &= (CRC.Calc16(data, data.Length) == 0x0000);
return(isValid);
}
catch (FitException)
{
return(false);
}
}
/// <summary>
/// Recompute the header CRC based on the current contents of the header object
/// </summary>
public void UpdateCRC()
{
using (MemoryStream ms = new MemoryStream())
{
Write(ms);
byte[] headerBuffer = ms.ToArray();
Crc = CRC.Calc16(headerBuffer, headerBuffer.Length - 2);
}
}
/// <summary>
/// Updates the data size and CRC in the file header
/// Updates file CRC
/// </summary>
public void Close()
{
if (open == false)
{
throw new FitException("Encode:Close - Encode not opened yet, must call Encode:Open()");
}
// Rewrites the header now that the datasize is known
header.DataSize = (uint)(fitDest.Length - header.Size);
header.UpdateCRC();
header.Write(fitDest);
// Compute and write the file CRC to the end of the file
byte[] data = new byte[fitDest.Length];
fitDest.Position = 0;
fitDest.Read(data, 0, data.Length);
ushort fileCrc = CRC.Calc16(data, data.Length);
byte[] buffer = BitConverter.GetBytes(fileCrc);
fitDest.Write(buffer, 0, 2);
}
/// <summary>
/// Reads a FIT binary file.
/// </summary>
/// <param name="fitStream">Seekable (file)stream to parse.</param>
/// <returns>
/// Returns true if reading finishes successfully.
/// </returns>
public bool Read(Stream fitStream)
{
bool readOK = true;
try
{
// Attempt to read header
fileHeader = new Header(fitStream);
readOK &= fileHeader.IsValid();
if (!readOK)
{
throw new FitException("FIT decode error: File is not FIT format. Check file header data type.");
}
if ((fileHeader.ProtocolVersion & Fit.ProtocolVersionMajorMask) > (Fit.ProtocolMajorVersion << Fit.ProtocolVersionMajorShift))
{
// The decoder does not support decode accross protocol major revisions
throw new FitException(String.Format("FIT decode error: Protocol Version {0}.X not supported by SDK Protocol Ver{1}.{2} ", (fileHeader.ProtocolVersion & Fit.ProtocolVersionMajorMask) >> Fit.ProtocolVersionMajorShift, Fit.ProtocolMajorVersion, Fit.ProtocolMinorVersion));
}
// Read data messages and definitions
while (fitStream.Position < fitStream.Length - 2)
{
DecodeNextMessage(fitStream);
}
// Is the file CRC ok?
byte[] data = new byte[fitStream.Length];
fitStream.Position = 0;
fitStream.Read(data, 0, data.Length);
readOK &= (CRC.Calc16(data, data.Length) == 0x0000);
}
catch (EndOfStreamException e)
{
readOK = false;
Debug.WriteLine("{0} caught and ignored. ", e.GetType().Name);
throw new FitException("Decode:Read - Unexpected End of File", e);
}
return(readOK);
}
