public override int Read(byte[] buffer, int offset, int count)
{
CheckDisposed();
EnsureReadable();
if (_inputBuffer.Length < count)
{
var readBuffer = new byte[PreferredBufferSize];
var read = default(int);
try
{
read = _innerStream.Read(readBuffer, 0, readBuffer.Length);
}
catch (IOException)
{
_ioFailed = true;
throw;
}
if (read != 0)
{
if (_compression)
{
_inflate.OutputBuffer = _compressionBuffer;
_inflate.AvailableBytesOut = _compressionBuffer.Length;
_inflate.NextOut = 0;
_inflate.InputBuffer = readBuffer;
_inflate.AvailableBytesIn = read;
_inflate.NextIn = 0;
var rc = _inflate.Inflate(Ionic.Zlib.FlushType.None);
if (rc != Ionic.Zlib.ZlibConstants.Z_OK)
{
throw new IOException($"Error '{rc}' while decompressing the data.");
}
if (_inflate.AvailableBytesIn != 0)
{
throw new IOException("Decompression buffer too small.");
}
readBuffer = _compressionBuffer;
read = _inflate.NextOut;
}
_inputBuffer.AddRange(readBuffer, read);
}
}
var dataLength = _inputBuffer.ReadInto(ref buffer, offset, count);
_position += dataLength;
return(dataLength);
}
/// <summary>
/// OnEmulation event handler
/// </summary>
protected override void OnEmulation()
{
// Are we at the end of the file?
if (_reader == null || _reader.EndOfStream)
{
// Yes. Re-open it from the beginning
FileStream stream = new FileStream(_filePath, FileMode.Open, FileAccess.Read, FileShare.Read);
_reader = new StreamReader(stream);
}
// Read a line from the file
string line = _reader.ReadLine();
// Don't write to the buffer if it's full
if (line != null)
{
if (ReadBuffer.Count + line.Length > ReadBuffer.Capacity)
{
return;
}
// Write the string
ReadBuffer.AddRange(Encoding.ASCII.GetBytes(line));
}
// Sleep
#if PocketPC
Thread.Sleep((int)_ReadInterval.TotalMilliseconds);
#else
Thread.Sleep(_readInterval);
#endif
}
/// <summary>
/// Writes the sentence to client.
/// </summary>
/// <param name="sentence">The sentence.</param>
protected void WriteSentenceToClient(NmeaSentence sentence)
{
// Get a byte array of the sentence
byte[] sentenceBytes = sentence.ToByteArray();
/* Some customers were found to make an emulator, but then not actually read from it.
* To prevent huge buffers, we will only write a sentence if the buffer can handle it.
* Otherwise, we'll ignore it completely.
*/
if (ReadBuffer.Count + sentenceBytes.Length + 2 > ReadBuffer.Capacity)
{
return;
}
// Add the bytes
ReadBuffer.AddRange(sentenceBytes);
// Add a CrLf
ReadBuffer.Add(13);
ReadBuffer.Add(10);
}
