public static Result libusb_get_string_descriptor(this ILibUsb lib, IntPtr deviceHandle,
byte index, ushort langId, IntPtr data, int length)
{
return(lib.libusb_control_transfer(deviceHandle,
(byte)EndpointDirection.In,
(byte)StandardRequest.LIBUSB_REQUEST_GET_DESCRIPTOR,
(ushort)(((byte)DescriptorType.LIBUSB_DT_STRING << 8) | index),
langId,
data,
(ushort)length,
1000));
}
static LibUsb()
{
switch (Environment.OSVersion.Platform)
{
case PlatformID.MacOSX:
case PlatformID.Unix:
_libUsb = new LibUsbMac();
break;
case PlatformID.Win32NT:
case PlatformID.Win32S:
case PlatformID.Win32Windows:
case PlatformID.WinCE:
_libUsb = new LibUsbWindows();
break;
}
}
private static unsafe string GetStringDescriptor(ILibUsb impl, IntPtr deviceHandle, byte index,
string fallback)
{
const int Buffer = 255;
byte[] str = new byte[Buffer];
if (index > 0)
{
fixed(byte *ptr = str)
{
var res = impl.libusb_get_string_descriptor(deviceHandle, 0, 0, new IntPtr(ptr), Buffer);
if ((int)res < 4)
{
return(fallback);
}
var langId = (ushort)(str[2] | (str[3] << 8));
res = impl.libusb_get_string_descriptor(deviceHandle, index, langId, new IntPtr(ptr), Buffer);
if (res < 0)
{
return(fallback);
}
if (str[1] != (int)DescriptorType.LIBUSB_DT_STRING)
{
return(fallback);
}
if (str[0] > (int)res)
{
return(fallback);
}
return(Encoding.Unicode.GetString(str, 2, (int)res));
}
}
return(fallback);
}
