/** \ingroup desc
* Get a USB configuration descriptor with a specific bConfigurationValue.
* This is a non-blocking function which does not involve any requests being
* sent to the device.
*
* \param dev a device
* \param bConfigurationValue the bConfigurationValue of the configuration you
* wish to retrieve
* \param config output location for the USB configuration descriptor. Only
* valid if 0 was returned. Must be freed with libusb_free_config_descriptor()
* after use.
* \returns 0 on success
* \returns LIBUSB_ERROR_NOT_FOUND if the configuration does not exist
* \returns another LIBUSB_ERROR code on error
* \see libusb_get_active_config_descriptor()
* \see libusb_get_config_descriptor()
*/
int API_EXPORTED libusb_get_config_descriptor_by_value(libusb_device *dev,
uint8_t bConfigurationValue, struct libusb_config_descriptor **config)
{
int idx;
int r = usbi_get_config_index_by_value(dev, bConfigurationValue, &idx);
if (r < 0)
return r;
else if (idx == -1)
return LIBUSB_ERROR_NOT_FOUND;
else
return libusb_get_config_descriptor(dev, (uint8_t) idx, config);
}
/** \ingroup desc
* Get a USB configuration descriptor with a specific bConfigurationValue.
* This is a non-blocking function which does not involve any requests being
* sent to the device.
*
* \param dev a device
* \param bConfigurationValue the bConfigurationValue of the configuration you
* wish to retrieve
* \param config output location for the USB configuration descriptor. Only
* valid if 0 was returned. Must be freed with libusb_free_config_descriptor()
* after use.
* \returns 0 on success
* \returns LIBUSB_ERROR_NOT_FOUND if the configuration does not exist
* \returns another LIBUSB_ERROR code on error
* \see libusb_get_active_config_descriptor()
* \see libusb_get_config_descriptor()
*/
int API_EXPORTED libusb_get_config_descriptor_by_value(libusb_device *dev,
uint8_t bConfigurationValue, struct libusb_config_descriptor **config)
{
int r, idx, host_endian;
unsigned char *buf = NULL;
if (usbi_backend->get_config_descriptor_by_value) {
r = usbi_backend->get_config_descriptor_by_value(dev,
bConfigurationValue, &buf, &host_endian);
if (r < 0)
return r;
return raw_desc_to_config(dev->ctx, buf, r, host_endian, config);
}
r = usbi_get_config_index_by_value(dev, bConfigurationValue, &idx);
if (r < 0)
return r;
else if (idx == -1)
return LIBUSB_ERROR_NOT_FOUND;
else
return libusb_get_config_descriptor(dev, (uint8_t) idx, config);
}
