public bool WriteUSB(byte[] buf)
{
for (int tries = 0; tries < 3; ++tries)
{
unsafe
{
// write the data - the file handle is in overlapped mode, so we have to do
// this as an overlapped write with an OVERLAPPED structure and an event to
// monitor for completion
Overlapped o = new Overlapped(0, 0, evov.SafeWaitHandle.DangerousGetHandle(), null);
NativeOverlapped *no = o.Pack(null, null);
IntPtr hbuf = Marshal.AllocHGlobal(buf.Length);
try
{
Marshal.Copy(buf, 0, hbuf, buf.Length);
HIDImports.WriteFile(fp, hbuf, buf.Length, IntPtr.Zero, no);
// wait briefly for the write to complete
if (evov.WaitOne(250))
{
// successful completion - get the result
UInt32 actual;
int result = HIDImports.GetOverlappedResult(fp, no, out actual, 0);
Overlapped.Unpack(no);
Overlapped.Free(no);
if (result == 0)
{
// the write failed - try re-opening the handle and go back
// for another try
TryReopenHandle();
continue;
}
else if (actual != buf.Length)
{
// length is wrong - the write failed
return(false);
}
else
{
// success
return(true);
}
}
else
{
// The write timed out. Cancel the write and try reopening the handle.
HIDImports.CancelIo(fp);
Overlapped.Unpack(no);
Overlapped.Free(no);
if (TryReopenHandle())
{
continue;
}
return(false);
}
}
finally
{
Marshal.FreeHGlobal(hbuf);
}
}
}
// maximum retries exceeded - return failure
return(false);
}
