XN_C_API XnStatus xnUSBGetDeviceSpeed(XN_USB_DEV_HANDLE pDevHandle, XnUSBDeviceSpeed* pDevSpeed)
{
// validate parameters
XN_VALIDATE_USB_INIT();
XN_VALIDATE_DEVICE_HANDLE(pDevHandle);
XN_VALIDATE_OUTPUT_PTR(pDevSpeed);
*pDevSpeed = pDevHandle->nDevSpeed;
return (XN_STATUS_OK);
}
XN_C_API XnStatus xnUSBSetInterface(XN_USB_DEV_HANDLE pDevHandle, XnUInt8 nInterface, XnUInt8 nAltInterface)
{
// validate parameters
XN_VALIDATE_USB_INIT();
XN_VALIDATE_DEVICE_HANDLE(pDevHandle);
int rc = libusb_set_interface_alt_setting(pDevHandle->hDevice, nInterface, nAltInterface);
if (rc != 0)
{
return (XN_STATUS_USB_SET_INTERFACE_FAILED);
}
pDevHandle->nInterface = nInterface;
pDevHandle->nAltSetting = nAltInterface;
return (XN_STATUS_OK);
}
XN_C_API XnStatus xnUSBCloseDevice(XN_USB_DEV_HANDLE pDevHandle)
{
// validate parameters
XN_VALIDATE_USB_INIT();
XN_VALIDATE_DEVICE_HANDLE(pDevHandle);
int rc = libusb_release_interface(pDevHandle->hDevice, pDevHandle->nInterface);
if (0 != rc)
{
return (XN_STATUS_USB_DEVICE_CLOSE_FAILED);
}
libusb_close(pDevHandle->hDevice);
XN_FREE_AND_NULL(pDevHandle);
return (XN_STATUS_OK);
}
XN_C_API XnStatus xnUSBOpenEndPoint(XN_USB_DEV_HANDLE pDevHandle, XnUInt16 nEndPointID, XnUSBEndPointType nEPType, XnUSBDirectionType nDirType, XN_USB_EP_HANDLE* pEPHandlePtr)
{
// validate parameters
XN_VALIDATE_USB_INIT();
XN_VALIDATE_DEVICE_HANDLE(pDevHandle);
XN_VALIDATE_OUTPUT_PTR(pEPHandlePtr);
// get the device from the handle
libusb_device* pDevice = libusb_get_device(pDevHandle->hDevice);
// get the configuration descriptor
libusb_config_descriptor* pConfig;
int rc = libusb_get_active_config_descriptor(pDevice, &pConfig);
if (rc != 0)
{
return (XN_STATUS_USB_CONFIG_QUERY_FAILED);
}
// make sure configuration contains the interface we need
if (pConfig->bNumInterfaces <= pDevHandle->nInterface)
{
libusb_free_config_descriptor(pConfig);
return (XN_STATUS_USB_INTERFACE_QUERY_FAILED);
}
// take that interface
const libusb_interface* pInterface = &pConfig->interface[pDevHandle->nInterface];
// make sure interface contains the alternate setting we work with
if (pInterface->num_altsetting <= pDevHandle->nAltSetting)
{
libusb_free_config_descriptor(pConfig);
return (XN_STATUS_USB_INTERFACE_QUERY_FAILED);
}
// take that setting
const libusb_interface_descriptor* pInterfaceDesc = &pInterface->altsetting[pDevHandle->nAltSetting];
// search for the requested endpoint
const libusb_endpoint_descriptor* pEndpointDesc = NULL;
for (uint8_t i = 0; i < pInterfaceDesc->bNumEndpoints; ++i)
{
if (pInterfaceDesc->endpoint[i].bEndpointAddress == nEndPointID)
{
pEndpointDesc = &pInterfaceDesc->endpoint[i];
break;
}
}
if (pEndpointDesc == NULL)
{
libusb_free_config_descriptor(pConfig);
return (XN_STATUS_USB_ENDPOINT_NOT_FOUND);
}
libusb_transfer_type transfer_type = (libusb_transfer_type)(pEndpointDesc->bmAttributes & 0x3); // lower 2-bits
// calculate max packet size
// NOTE: we do not use libusb functions (libusb_get_max_packet_size/libusb_get_max_iso_packet_size) because
// they hace a bug and does not consider alternative interface
XnUInt32 nMaxPacketSize = 0;
if (transfer_type == LIBUSB_TRANSFER_TYPE_ISOCHRONOUS)
{
XnUInt32 wMaxPacketSize = pEndpointDesc->wMaxPacketSize;
// bits 11 and 12 mark the number of additional transactions, bits 0-10 mark the size
XnUInt32 nAdditionalTransactions = wMaxPacketSize >> 11;
XnUInt32 nPacketSize = wMaxPacketSize & 0x7FF;
nMaxPacketSize = (nAdditionalTransactions + 1) * (nPacketSize);
}
