|
private ReadFile ( |
||
| handle | ||
| buffer | byte | |
| bytesToRead | int | |
| bytesRead | ||
| overlapped | ||
| return | bool | |
public unsafe override int Read(byte[] buffer, int offset, int count)
{
Throw.If.OutOfRange(buffer, offset, count); uint bytesTransferred;
IntPtr @event = NativeMethods.CreateManualResetEventOrThrow();
HandleAcquireIfOpenOrFail(); UpdateSettings();
try
{
fixed(byte *ptr = buffer)
{
var overlapped = stackalloc NativeOverlapped[1];
overlapped[0].EventHandle = @event;
NativeMethods.OverlappedOperation(_handle, @event, ReadTimeout, _closeEventHandle,
NativeMethods.ReadFile(_handle, ptr + offset, count, IntPtr.Zero, overlapped),
overlapped, out bytesTransferred);
return((int)bytesTransferred);
}
}
finally
{
HandleRelease();
NativeMethods.CloseHandle(@event);
}
}
// Buffer needs to be big enough for the largest report, plus a byte
// for the Report ID.
public unsafe override int Read(byte[] buffer, int offset, int count)
{
Throw.If.OutOfRange(buffer, offset, count); uint bytesTransferred;
IntPtr @event = NativeMethods.CreateManualResetEventOrThrow();
HandleAcquireIfOpenOrFail();
try
{
lock (_readSync)
{
int minIn = Device.GetMaxInputReportLength();
if (minIn <= 0)
{
throw new IOException("Can't read from this device.");
}
if (_readBuffer == null || _readBuffer.Length < Math.Max(count, minIn))
{
Array.Resize(ref _readBuffer, Math.Max(count, minIn));
}
fixed(byte *ptr = _readBuffer)
{
var overlapped = stackalloc NativeOverlapped[1];
overlapped[0].EventHandle = @event;
NativeMethods.OverlappedOperation(_handle, @event, ReadTimeout, _closeEventHandle,
NativeMethods.ReadFile(_handle, ptr, Math.Max(count, minIn), IntPtr.Zero, overlapped),
overlapped, out bytesTransferred);
if (count > (int)bytesTransferred)
{
count = (int)bytesTransferred;
}
Array.Copy(_readBuffer, 0, buffer, offset, count);
return(count);
}
}
}
finally
{
HandleRelease();
NativeMethods.CloseHandle(@event);
}
}
// Buffer needs to be big enough for the largest report, plus a byte
// for the Report ID.
public unsafe override int Read(byte[] buffer, int offset, int count)
{
Throw.If.OutOfRange(buffer, offset, count); uint bytesTransferred;
IntPtr @event = NativeMethods.CreateManualResetEventOrThrow();
HandleAcquireIfOpenOrFail();
try
{
lock (_readSync)
{
int maxIn = _device.MaxInputReportLength;
Array.Resize(ref _readBuffer, maxIn); if (count > maxIn)
{
count = maxIn;
}
fixed(byte *ptr = _readBuffer)
{
var overlapped = stackalloc NativeOverlapped[1];
overlapped[0].EventHandle = @event;
NativeMethods.OverlappedOperation(_handle, @event, ReadTimeout, _closeEventHandle,
NativeMethods.ReadFile(_handle, ptr, maxIn, IntPtr.Zero, overlapped),
overlapped, out bytesTransferred);
if (count > (int)bytesTransferred)
{
count = (int)bytesTransferred;
}
Array.Copy(_readBuffer, 0, buffer, offset, count);
return(count);
}
}
}
finally
{
HandleRelease();
NativeMethods.CloseHandle(@event);
}
}