// Protected implementation of Dispose pattern.
protected virtual void Dispose(bool disposing)
{
if (disposed)
{
return;
}
if (disposing)
{
// Free any other managed objects here.
if (asyncReadOn)
{
asyncReadOn = false;
readThread.Join(readTimeoutInMillisecs);
if (readThread.IsAlive)
{
readThread.Abort();
}
}
}
// Free any UN-managed objects here.
// so we are not reading or writing as the device gets closed
lock (syncLock)
{
if (isOpen)
{
HidApi.hid_close(DeviceHandle);
DeviceHandle = IntPtr.Zero;
}
}
HidApi.hid_exit();
// mark object as having been disposed
disposed = true;
}
public string GetErrorString()
{
AssertValidDev();
IntPtr ret = HidApi.hid_error(DeviceHandle);
// I can not find the info in the docs, but guess this frees
// the ret pointer after we created a managed string object
// else this would be a memory leak
return(Marshal.PtrToStringAuto(ret));
}
// HIDAPI does not provide any way to get or parse the HID Report Descriptor,
// This means you must know in advance what it the report size for your device.
// For this reason, reportLen is a necessary parameter to the constructor.
//
// Serial Number is optional, pass null (do NOT pass an empty string) if it is unknown.
//
public USBDevice(ushort VendorID
, ushort ProductID
, string serial_number
, bool HasReportIDs = true
, int defaultInputReportLen = -1)
{
DeviceHandle = HidApi.hid_open(VendorID, ProductID, serial_number);
AssertValidDev();
DefaultInputReportLength = defaultInputReportLen;
hasReportIds = HasReportIDs;
}
public void GetFeatureReport(byte[] buffer, int length = -1)
{
AssertValidDev();
if (length < 0)
{
length = buffer.Length;
}
if (HidApi.hid_get_feature_report(DeviceHandle, buffer, (uint)length) < 0)
{
throw new Exception("failed to get feature report");
}
}
// All the string functions are in a little bit of trouble becasue
// wchar_t is 2 bytes on windows and 4 bytes on linux.
// So we should just alloc a hell load of space for the return buffer.
//
// We must divide Capacity / 4 because this takes the buffer length in multiples of
// wchar_t whoose length is 4 on Linux and 2 on Windows. So we allocate a big
// buffer beforehand and just divide the capacity by 4.
public string GetIndexedString(int index)
{
lock (syncLock)
{
AssertValidDev();
if (HidApi.hid_get_indexed_string(DeviceHandle, index, pOutBuf, (uint)pOutBuf.Capacity / 4) < 0)
{
throw new Exception("failed to get indexed string");
}
return(pOutBuf.ToString());
}
}
// Meaning OutputReport
private void WriteRaw(byte[] buffer, int length = -1)
{
AssertValidDev();
if (length < 0)
{
length = buffer.Length;
}
if (HidApi.hid_write(DeviceHandle, buffer, (uint)length) < 0)
{
throw new Exception("Failed to write.");
}
}
public string GetSerialNumberString()
{
lock (syncLock)
{
AssertValidDev();
pOutBuf.Clear();
if (HidApi.hid_get_serial_number_string(DeviceHandle, pOutBuf, (uint)pOutBuf.Capacity / 4) < 0)
{
throw new Exception("failed to get serial number string");
}
return(pOutBuf.ToString());
}
}
public string GetProductString()
{
lock (syncLock)
{
AssertValidDev();
pOutBuf.Clear();
if (HidApi.hid_get_product_string(DeviceHandle, pOutBuf, (uint)pOutBuf.Capacity / 4) < 0)
{
throw new Exception("failed to get product string");
}
return(pOutBuf.ToString());
}
}
// either everything is good, or throw exception
// Meaning InputReport
// This function is slightly different, as we must return the number of bytes read.
private int ReadRaw(byte[] buffer, int length = -1)
{
AssertValidDev();
if (length < 0)
{
length = buffer.Length;
}
int bytes_read = HidApi.hid_read_timeout(DeviceHandle, buffer, (uint)length, readTimeoutInMillisecs);
if (bytes_read < 0)
{
throw new Exception("Failed to Read.");
}
return(bytes_read);
}
// Meaning OutputReport
private int WriteRaw(byte[] buffer, int length = -1)
{
int byte_written = 0;
AssertValidDev();
if (length < 0)
{
length = buffer.Length;
}
byte_written = HidApi.hid_write(DeviceHandle, buffer, (uint)length);
if (byte_written < 0)
{
throw new Exception("Failed to write.");
}
return(byte_written);
}
private void ScanLoop()
{
var culture = CultureInfo.InvariantCulture;
Thread.CurrentThread.CurrentCulture = culture;
Thread.CurrentThread.CurrentUICulture = culture;
// The read has a timeout parameter, so every X milliseconds
// we check if the user wants us to continue scanning.
while (asyncScanOn)
{
try
{
IntPtr device_info = HidApi.hid_enumerate(vendorId, productId);
bool device_on_bus = device_info != IntPtr.Zero;
// freeing the enumeration releases the device,
// do it as soon as you can, so we dont block device from others
HidApi.hid_free_enumeration(device_info);
if (device_on_bus && !deviceConnected)
{
// just found new device
deviceConnected = true;
if (DeviceArrived != null)
{
DeviceArrived(this, EventArgs.Empty);
}
}
if (!device_on_bus && deviceConnected)
{
// just lost device connection
deviceConnected = false;
if (DeviceRemoved != null)
{
DeviceRemoved(this, EventArgs.Empty);
}
}
}
catch (Exception e)
{
// stop scan, user can manually restart again with StartAsyncScan()
asyncScanOn = false;
}
// when read 0 bytes, sleep and read again
Thread.Sleep(ScanIntervalInMillisecs);
}
}
// scanning for device when it is open by another process will return false
public static bool ScanOnce(ushort vid, ushort pid)
{
return(HidApi.hid_enumerate(vid, pid) != IntPtr.Zero);
}