def ctrl_transfer(self,
                      dev_handle,
                      bmRequestType,
                      bRequest,
                      wValue,
                      wIndex,
                      data_or_wLength,
                      timeout):
        request = _openusb_ctrl_request()
        request.setup.bmRequestType = bmRequestType
        request.setup.bRequest = bRequest
        request.setup.wValue
        request.setup.wIndex
        request.timeout = timeout

        direction = usb.util.ctrl_direction(bmRequestType)

        if direction == usb.util.CTRL_OUT:
            buffer = data_or_wLength
        else:
            buffer = _interop.as_array('\x00' * data_or_wLength)

        payload, request.length = buffer.buffer_info()
        request.payload = cast(payload, POINTER(c_uint8))

        _check(_lib.openusb_ctrl_xfer(dev_handle, 0, 0, byref(request)))

        if direction == usb.util.CTRL_OUT:
            return request.result.transferred_bytes
        else:
            return buffer[:request.result.transferred_bytes]

    def ctrl_transfer(self, bmRequestType, bRequest, wValue=0, wIndex=0, data_or_wLength=None, timeout=None):
        r"""Do a control transfer on the endpoint 0.

        This method is used to issue a control transfer over the
        endpoint 0(endpoint 0 is required to always be a control endpoint).

        The parameters bmRequestType, bRequest, wValue and wIndex are the
        same of the USB Standard Control Request format.

        Control requests may or may not have a data payload to write/read.
        In cases which it has, the direction bit of the bmRequestType
        field is used to infere the desired request direction. For
        host to device requests (OUT), data_or_wLength parameter is
        the data payload to send, and it must be a sequence type convertible
        to an array object. In this case, the return value is the number of data
        payload written. For device to host requests (IN), data_or_wLength
        is the wLength parameter of the control request specifying the
        number of bytes to read in data payload. In this case, the return
        value is the data payload read, as an array object.
        """
        if util.ctrl_direction(bmRequestType) == util.CTRL_OUT:
            a = _interop.as_array(data_or_wLength)
        elif data_or_wLength is None:
            a = 0
        else:
            a = data_or_wLength

        self._ctx.managed_open()

        return self._ctx.backend.ctrl_transfer(
            self._ctx.handle, bmRequestType, bRequest, wValue, wIndex, a, self.__get_timeout(timeout)
        )

    def ctrl_transfer(self,
                      dev_handle,
                      bmRequestType,
                      bRequest,
                      wValue,
                      wIndex,
                      data_or_wLength,
                      timeout):
        if usb.util.ctrl_direction(bmRequestType) == usb.util.CTRL_OUT:
            buff = data_or_wLength
        else:
            buff = _interop.as_array((0,) * data_or_wLength)

        addr, length = buff.buffer_info()
        length *= buff.itemsize

        ret = _check(_lib.libusb_control_transfer(dev_handle,
                                                  bmRequestType,
                                                  bRequest,
                                                  wValue,
                                                  wIndex,
                                                  cast(addr,
                                                       POINTER(c_ubyte)),
                                                  length,
                                                  timeout))

        if usb.util.ctrl_direction(bmRequestType) == usb.util.CTRL_OUT:
            return ret.value
        else:
            return buff[:ret.value]

    def write(self, endpoint, data, timeout = None):
        r"""Write data to the endpoint.

        This method is used to send data to the device. The endpoint parameter
        corresponds to the bEndpointAddress member whose endpoint you want to
        communicate with.

        The data parameter should be a sequence like type convertible to
        the array type (see array module).

        The timeout is specified in miliseconds.

        The method returns the number of bytes written.
        """
        backend = self._ctx.backend

        fn_map = {
                    util.ENDPOINT_TYPE_BULK:backend.bulk_write,
                    util.ENDPOINT_TYPE_INTR:backend.intr_write,
                    util.ENDPOINT_TYPE_ISO:backend.iso_write
                }

        intf, ep = self._ctx.setup_request(self, endpoint)
        fn = fn_map[util.endpoint_type(ep.bmAttributes)]

        return fn(
                self._ctx.handle,
                ep.bEndpointAddress,
                intf.bInterfaceNumber,
                _interop.as_array(data),
                self.__get_timeout(timeout)
            )

 def ctrl_transfer(self,
                   dev_handle,
                   bmRequestType,
                   bRequest,
                   wValue,
                   wIndex,
                   data_or_wLength,
                   timeout):
     if usb.util.ctrl_direction(bmRequestType) == usb.util.CTRL_OUT:
         address, length = data_or_wLength.buffer_info()
         length *= data_or_wLength.itemsize
         return _check(_lib.usb_control_msg(
             dev_handle,
             bmRequestType,
             bRequest,
             wValue,
             wIndex,
             cast(address, c_char_p),
             length,
             timeout
         ))
     else:
         data = _interop.as_array((0,) * data_or_wLength)
         read = int(_check(_lib.usb_control_msg(
             dev_handle,
             bmRequestType,
             bRequest,
             wValue,
             wIndex,
             cast(data.buffer_info()[0],
                  c_char_p),
             data_or_wLength,
             timeout
         )))
         return data[:read]

    def write(self, endpoint, data, interface=None, timeout=None):
        r"""Write data to the endpoint.

        This method is used to send data to the device. The endpoint parameter
        corresponds to the bEndpointAddress member whose endpoint you want to
        communicate with. The interface parameter is the bInterfaceNumber field
        of the interface descriptor which contains the endpoint. If you do not
        provide one, the first one found will be used, as explained in the
        set_interface_altsetting() method.

        The data parameter should be a sequence like type convertible to
        array type (see array module).

        The timeout is specified in miliseconds.

        The method returns the number of bytes written.
        """
        backend = self._ctx.backend

        fn_map = {
            util.ENDPOINT_TYPE_BULK: backend.bulk_write,
            util.ENDPOINT_TYPE_INTR: backend.intr_write,
            util.ENDPOINT_TYPE_ISO: backend.iso_write,
        }

        intf = self._ctx.get_interface(self, interface)
        fn = fn_map[self._ctx.get_endpoint_type(self, endpoint, intf)]
        self._ctx.managed_claim_interface(self, intf)

        return fn(
            self._ctx.handle, endpoint, intf.bInterfaceNumber, _interop.as_array(data), self.__get_timeout(timeout)
        )

 def intr_read(self, dev_handle, ep, intf, size, timeout):
     request = _openusb_intr_request()
     buffer = _interop.as_array('B', '\x00' * size)
     memset(byref(request), 0, sizeof(request))
     payload, request.length = buffer.buffer_info()
     request.payload = cast(payload, POINTER(c_uint8))
     request.timeout = timeout
     _check(_lib.openusb_intr_xfer(dev_handle, intf, ep, byref(request)))
     return buffer[:request.result.transferred_bytes]

    def ctrl_transfer(self, bmRequestType, bRequest, wValue=0, wIndex=0,
            data_or_wLength = None, timeout = None):
        r"""Do a control transfer on the endpoint 0.

        This method is used to issue a control transfer over the endpoint 0
        (endpoint 0 is required to always be a control endpoint).

        The parameters bmRequestType, bRequest, wValue and wIndex are the same
        of the USB Standard Control Request format.

        Control requests may or may not have a data payload to write/read.
        In cases which it has, the direction bit of the bmRequestType
        field is used to infer the desired request direction. For
        host to device requests (OUT), data_or_wLength parameter is
        the data payload to send, and it must be a sequence type convertible
        to an array object. In this case, the return value is the number
        of bytes written in the data payload. For device to host requests
        (IN), data_or_wLength is either the wLength parameter of the control
        request specifying the number of bytes to read in data payload, and
        the return value is an array object with data read, or an array
        object which the data will be read to, and the return value is the
        number of bytes read.
        """
        try:
            buff = util.create_buffer(data_or_wLength)
        except TypeError:
            buff = _interop.as_array(data_or_wLength)

        self._ctx.managed_open()

        # Thanks to Johannes Stezenbach to point me out that we need to
        # claim the recipient interface
        recipient = bmRequestType & 3
        rqtype = bmRequestType & (3 << 5)
        if recipient == util.CTRL_RECIPIENT_INTERFACE \
                and rqtype != util.CTRL_TYPE_VENDOR:
            interface_number = wIndex & 0xff
            self._ctx.managed_claim_interface(self, interface_number)

        ret = self._ctx.backend.ctrl_transfer(
                                    self._ctx.handle,
                                    bmRequestType,
                                    bRequest,
                                    wValue,
                                    wIndex,
                                    buff,
                                    self.__get_timeout(timeout))

        if isinstance(data_or_wLength, array.array) \
                or util.ctrl_direction(bmRequestType) == util.CTRL_OUT:
            return ret
        elif ret != len(buff) * buff.itemsize:
            return buff[:ret]
        else:
            return buff

 def __read(self, fn, dev_handle, ep, intf, size, timeout):
     data = _interop.as_array((0,) * size)
     address, length = data.buffer_info()
     length *= data.itemsize
     ret = int(_check(fn(
         dev_handle,
         ep,
         cast(address, c_char_p),
         length,
         timeout
     )))
     return data[:ret]

 def __read(self, fn, dev_handle, ep, intf, size, timeout):
     data = _interop.as_array((0,) * size)
     address, length = data.buffer_info()
     length *= data.itemsize
     transferred = c_int()
     _check(fn(dev_handle,
               ep,
               cast(address, POINTER(c_ubyte)),
               length,
               byref(transferred),
               timeout))
     return data[:transferred.value]

 def clear_halt(self, dev_handle, ep):
     bmRequestType = util.build_request_type(
                         util.CTRL_OUT,
                         util.CTRL_TYPE_STANDARD,
                         util.CTRL_RECIPIENT_ENDPOINT)
     self.ctrl_transfer(
         dev_handle,
         bmRequestType,
         0x03,
         0,
         ep,
         _interop.as_array(),
         1000)

 def __read(self, fn, dev_handle, ep, intf, size, timeout):
     data = _interop.as_array((0,) * size)
     address, length = data.buffer_info()
     length *= data.itemsize
     transferred = c_int()
     retval = fn(dev_handle,
               ep,
               cast(address, POINTER(c_ubyte)),
               length,
               byref(transferred),
               timeout)
     # do not assume LIBUSB_ERROR_TIMEOUT means no I/O.
     if not (transferred.value and retval == LIBUSB_ERROR_TIMEOUT):
         _check(retval)
     return data[:transferred.value]

 def __read(self, fn, dev_handle, ep, intf, data, size, timeout):
     read_into = (data != None)
     if not read_into:
         data = _interop.as_array((0,) * size)
     address, length = data.buffer_info()
     length *= data.itemsize
     ret = int(_check(fn(
                 dev_handle,
                 ep,
                 cast(address, c_char_p),
                 length,
                 timeout
             )))
     if read_into:
         return ret
     else:
         return data[:ret]

def to_array(data):
    return _interop.as_array(data)

def get_array_data2(length=10):
    data = list(range(length))
    data.reverse()
    return _interop.as_array(data)

def data_len(data):
    a = _interop.as_array(data)
    return len(data) * a.itemsize

def get_array_data1(length=10):
    return _interop.as_array(range(length))

 def iso_read(self, dev_handle, ep, intf, size, timeout):
     data = _interop.as_array('\x00' * size)
     handler = _IsoTransferHandler(dev_handle, ep, data, timeout)
     return data[:handler.submit(self.ctx)]