DWORD
GetDeviceCapabilities(
DeviceType device_type,
UINT device_id,
DWORD_PTR capabilities,
DWORD capabilities_size)
{
MMRESULT result;
DWORD ioctl;
HANDLE handle;
DWORD bytes_returned;
BOOL device_io_result;
ASSERT(capabilities);
/* Choose the right IOCTL for the job */
if ( IsWaveDevice(device_type) )
ioctl = IOCTL_WAVE_GET_CAPABILITIES;
else if ( IsMidiDevice(device_type) )
ioctl = IOCTL_MIDI_GET_CAPABILITIES;
else if ( IsAuxDevice(device_type) )
return MMSYSERR_NOTSUPPORTED; /* TODO */
else
return MMSYSERR_NOTSUPPORTED;
result = OpenKernelDevice(device_type,
device_id,
GENERIC_READ,
&handle);
if ( result != MMSYSERR_NOERROR )
{
DPRINT("Failed to open kernel device\n");
return result;
}
device_io_result = DeviceIoControl(handle,
ioctl,
NULL,
0,
(LPVOID) capabilities,
capabilities_size,
&bytes_returned,
NULL);
/* Translate result */
if ( device_io_result )
result = MMSYSERR_NOERROR;
else
result = ErrorToMmResult(GetLastError());
/* Clean up and return */
CloseKernelDevice(handle);
return result;
}
MMRESULT
OpenKernelDevice(
DeviceType device_type,
UINT device_id,
DWORD access,
HANDLE* handle)
{
MMRESULT result;
WCHAR device_name[MAX_DEVICE_NAME_LENGTH];
DWORD open_flags = 0;
ASSERT(handle);
/* Glue the base device name and the ID together */
result = CobbleDeviceName(device_type, device_id, device_name);
DPRINT("Opening kernel device %ls\n", device_name);
if ( result != MMSYSERR_NOERROR )
return result;
/* We want overlapped I/O when writing */
if ( access != GENERIC_READ )
open_flags = FILE_FLAG_OVERLAPPED;
/* Now try opening... */
*handle = CreateFile(device_name,
access,
FILE_SHARE_WRITE,
NULL,
OPEN_EXISTING,
open_flags,
NULL);
if ( *handle == INVALID_HANDLE_VALUE )
return ErrorToMmResult(GetLastError());
return MMSYSERR_NOERROR;
}
MMRESULT
GetDeviceData(
HANDLE device_handle,
DWORD ioctl,
PBYTE output_buffer,
DWORD buffer_size)
{
OVERLAPPED overlap;
DWORD bytes_returned;
BOOL success;
DWORD transfer;
DPRINT("GetDeviceData\n");
memset(&overlap, 0, sizeof(overlap));
overlap.hEvent = CreateEvent(NULL, FALSE, FALSE, NULL);
if ( ! overlap.hEvent )
return MMSYSERR_NOMEM;
success = DeviceIoControl(device_handle,
ioctl,
NULL,
0,
output_buffer,
buffer_size,
&bytes_returned,
&overlap);
if ( ! success )
{
if ( GetLastError() == ERROR_IO_PENDING )
{
if ( ! GetOverlappedResult(device_handle, &overlap, &transfer, TRUE) )
{
CloseHandle(overlap.hEvent);
return ErrorToMmResult(GetLastError());
}
}
else
{
CloseHandle(overlap.hEvent);
return ErrorToMmResult(GetLastError());
}
}
while ( TRUE )
{
SetEvent(overlap.hEvent);
if ( WaitForSingleObjectEx(overlap.hEvent, 0, TRUE) != WAIT_IO_COMPLETION )
{
break;
}
}
CloseHandle(overlap.hEvent);
return MMSYSERR_NOERROR;
}
