libusb.h

最新的libusb库

 * Calling this function only makes sense from a transfer callback function,
 * or situations where you have already allocated a suitably sized buffer at
 * transfer->buffer.
 *
 * \param transfer a transfer
 * \returns pointer to the first byte of the data section
 */
static inline unsigned char *libusb_control_transfer_get_data(
	struct libusb_transfer *transfer)
{
	return transfer->buffer + LIBUSB_CONTROL_SETUP_SIZE;
}

/** \ingroup asyncio
 * Get the control setup packet of a control transfer. This convenience
 * function is here to remind you that the control setup occupies the first
 * 8 bytes of the transfer data buffer.
 *
 * Calling this function only makes sense from a transfer callback function,
 * or situations where you have already allocated a suitably sized buffer at
 * transfer->buffer.
 *
 * \param transfer a transfer
 * \returns a casted pointer to the start of the transfer data buffer
 */
static inline struct libusb_control_setup *libusb_control_transfer_get_setup(
	struct libusb_transfer *transfer)
{
	return (struct libusb_control_setup *) transfer->buffer;
}

/** \ingroup asyncio
 * Helper function to populate the setup packet (first 8 bytes of the data
 * buffer) for a control transfer. The wIndex, wValue and wLength values should
 * be given in host-endian byte order.
 * 
 * \param buffer buffer to output the setup packet into
 * \param bmRequestType see the
 * \ref libusb_control_setup::bmRequestType "bmRequestType" field of
 * \ref libusb_control_setup
 * \param bRequest see the
 * \ref libusb_control_setup::bRequest "bRequest" field of 
 * \ref libusb_control_setup
 * \param wValue see the
 * \ref libusb_control_setup::wValue "wValue" field of 
 * \ref libusb_control_setup
 * \param wIndex see the
 * \ref libusb_control_setup::wIndex "wIndex" field of 
 * \ref libusb_control_setup
 * \param wLength see the
 * \ref libusb_control_setup::wLength "wLength" field of 
 * \ref libusb_control_setup
 */
static inline void libusb_fill_control_setup(unsigned char *buffer,
	uint8_t bmRequestType, uint8_t bRequest, uint16_t wValue, uint16_t wIndex,
	uint16_t wLength)
{
	struct libusb_control_setup *setup = (struct libusb_control_setup *) buffer;
	setup->bmRequestType = bmRequestType;
	setup->bRequest = bRequest;
	setup->wValue = libusb_cpu_to_le16(wValue);
	setup->wIndex = libusb_cpu_to_le16(wIndex);
	setup->wLength = libusb_cpu_to_le16(wLength);
}

struct libusb_transfer *libusb_alloc_transfer(int iso_packets);
int libusb_submit_transfer(struct libusb_transfer *transfer);
int libusb_cancel_transfer(struct libusb_transfer *transfer);
void libusb_free_transfer(struct libusb_transfer *transfer);

/** \ingroup asyncio
 * Helper function to populate the required \ref libusb_transfer fields
 * for a control transfer.
 *
 * If you pass a transfer buffer to this function, the first 8 bytes will
 * be interpreted as a control setup packet, and the wLength field will be
 * used to automatically populate the \ref libusb_transfer::length "length"
 * field of the transfer. Therefore the recommended approach is:
 * -# Allocate a suitably sized data buffer (including space for control setup)
 * -# Call libusb_fill_control_setup()
 * -# If this is a host-to-device transfer with a data stage, put the data
 *    in place after the setup packet
 * -# Call this function
 * -# Call libusb_submit_transfer()
 *
 * It is also legal to pass a NULL buffer to this function, in which case this
 * function will not attempt to populate the length field. Remember that you
 * must then populate the buffer and length fields later.
 *
 * \param transfer the transfer to populate
 * \param dev_handle handle of the device that will handle the transfer
 * \param buffer data buffer. If provided, this function will interpret the
 * first 8 bytes as a setup packet and infer the transfer length from that.
 * \param callback callback function to be invoked on transfer completion
 * \param user_data user data to pass to callback function
 * \param timeout timeout for the transfer in milliseconds
 */
static inline void libusb_fill_control_transfer(
	struct libusb_transfer *transfer, libusb_device_handle *dev_handle,
	unsigned char *buffer, libusb_transfer_cb_fn callback, void *user_data,
	unsigned int timeout)
{
	struct libusb_control_setup *setup = (struct libusb_control_setup *) buffer;
	transfer->dev_handle = dev_handle;
	transfer->endpoint = 0;
	transfer->type = LIBUSB_TRANSFER_TYPE_CONTROL;
	transfer->timeout = timeout;
	transfer->buffer = buffer;
	if (setup)
		transfer->length = LIBUSB_CONTROL_SETUP_SIZE
			+ libusb_le16_to_cpu(setup->wLength);
	transfer->user_data = user_data;
	transfer->callback = callback;
}

/** \ingroup asyncio
 * Helper function to populate the required \ref libusb_transfer fields
 * for a bulk transfer.
 *
 * \param transfer the transfer to populate
 * \param dev_handle handle of the device that will handle the transfer
 * \param endpoint address of the endpoint where this transfer will be sent
 * \param buffer data buffer
 * \param length length of data buffer
 * \param callback callback function to be invoked on transfer completion
 * \param user_data user data to pass to callback function
 * \param timeout timeout for the transfer in milliseconds
 */
static inline void libusb_fill_bulk_transfer(struct libusb_transfer *transfer,
	libusb_device_handle *dev_handle, unsigned char endpoint,
	unsigned char *buffer, int length, libusb_transfer_cb_fn callback,
	void *user_data, unsigned int timeout)
{
	transfer->dev_handle = dev_handle;
	transfer->endpoint = endpoint;
	transfer->type = LIBUSB_TRANSFER_TYPE_BULK;
	transfer->timeout = timeout;
	transfer->buffer = buffer;
	transfer->length = length;
	transfer->user_data = user_data;
	transfer->callback = callback;
}

/** \ingroup asyncio
 * Helper function to populate the required \ref libusb_transfer fields
 * for an interrupt transfer.
 *
 * \param transfer the transfer to populate
 * \param dev_handle handle of the device that will handle the transfer
 * \param endpoint address of the endpoint where this transfer will be sent
 * \param buffer data buffer
 * \param length length of data buffer
 * \param callback callback function to be invoked on transfer completion
 * \param user_data user data to pass to callback function
 * \param timeout timeout for the transfer in milliseconds
 */
static inline void libusb_fill_interrupt_transfer(
	struct libusb_transfer *transfer, libusb_device_handle *dev_handle,
	unsigned char endpoint, unsigned char *buffer, int length,
	libusb_transfer_cb_fn callback, void *user_data, unsigned int timeout)
{
	transfer->dev_handle = dev_handle;
	transfer->endpoint = endpoint;
	transfer->type = LIBUSB_TRANSFER_TYPE_INTERRUPT;
	transfer->timeout = timeout;
	transfer->buffer = buffer;
	transfer->length = length;
	transfer->user_data = user_data;
	transfer->callback = callback;
}

/** \ingroup asyncio
 * Helper function to populate the required \ref libusb_transfer fields
 * for an isochronous transfer.
 *
 * \param transfer the transfer to populate
 * \param dev_handle handle of the device that will handle the transfer
 * \param endpoint address of the endpoint where this transfer will be sent
 * \param buffer data buffer
 * \param length length of data buffer
 * \param num_iso_packets the number of isochronous packets
 * \param callback callback function to be invoked on transfer completion
 * \param user_data user data to pass to callback function
 * \param timeout timeout for the transfer in milliseconds
 */
static inline void libusb_fill_iso_transfer(struct libusb_transfer *transfer,
	libusb_device_handle *dev_handle, unsigned char endpoint,
	unsigned char *buffer, int length, int num_iso_packets,
	libusb_transfer_cb_fn callback, void *user_data, unsigned int timeout)
{
	transfer->dev_handle = dev_handle;
	transfer->endpoint = endpoint;
	transfer->type = LIBUSB_TRANSFER_TYPE_ISOCHRONOUS;
	transfer->timeout = timeout;
	transfer->buffer = buffer;
	transfer->length = length;
	transfer->num_iso_packets = num_iso_packets;
	transfer->user_data = user_data;
	transfer->callback = callback;
}

/** \ingroup asyncio
 * Convenience function to set the length of all packets in an isochronous
 * transfer, based on the num_iso_packets field in the transfer structure.
 *
 * \param transfer a transfer
 * \param length the length to set in each isochronous packet descriptor
 * \see libusb_get_max_packet_size()
 */
static inline void libusb_set_iso_packet_lengths(
	struct libusb_transfer *transfer, unsigned int length)
{
	int i;
	for (i = 0; i < transfer->num_iso_packets; i++)
		transfer->iso_packet_desc[i].length = length;
}

/** \ingroup asyncio
 * Convenience function to locate the position of an isochronous packet
 * within the buffer of an isochronous transfer.
 *
 * This is a thorough function which loops through all preceding packets,
 * accumulating their lengths to find the position of the specified packet.
 * Typically you will assign equal lengths to each packet in the transfer,
 * and hence the above method is sub-optimal. You may wish to use
 * libusb_get_iso_packet_buffer_simple() instead.
 * 
 * \param transfer a transfer
 * \param packet the packet to return the address of
 * \returns the base address of the packet buffer inside the transfer buffer,
 * or NULL if the packet does not exist.
 * \see libusb_get_iso_packet_buffer_simple()
 */
static inline unsigned char *libusb_get_iso_packet_buffer(
	struct libusb_transfer *transfer, unsigned int packet)
{
	int i;
	size_t offset = 0;

	if (packet >= transfer->num_iso_packets)
		return NULL;

	for (i = 0; i < packet; i++)
		offset += transfer->iso_packet_desc[i].length;

	return transfer->buffer + offset;
}

/** \ingroup asyncio
 * Convenience function to locate the position of an isochronous packet
 * within the buffer of an isochronous transfer, for transfers where each
 * packet is of identical size.
 *
 * This function relies on the assumption that every packet within the transfer
 * is of identical size to the first packet. Calculating the location of
 * the packet buffer is then just a simple calculation:
 * <tt>buffer + (packet_size * packet)</tt>
 *
 * Do not use this function on transfers other than those that have identical
 * packet lengths for each packet.
 *
 * \param transfer a transfer
 * \param packet the packet to return the address of
 * \returns the base address of the packet buffer inside the transfer buffer,
 * or NULL if the packet does not exist.
 * \see libusb_get_iso_packet_buffer()
 */
static inline unsigned char *libusb_get_iso_packet_buffer_simple(
	struct libusb_transfer *transfer, unsigned int packet)
{
	if (packet >= transfer->num_iso_packets)
		return NULL;
	
	return transfer->buffer + (transfer->iso_packet_desc[0].length * packet);
}

/* sync I/O */

int libusb_control_transfer(libusb_device_handle *dev_handle,
	uint8_t request_type, uint8_t request, uint16_t value, uint16_t index,
	unsigned char *data, uint16_t length, unsigned int timeout);

int libusb_bulk_transfer(libusb_device_handle *dev_handle,
	unsigned char endpoint, unsigned char *data, int length,
	int *actual_length, unsigned int timeout);

int libusb_interrupt_transfer(libusb_device_handle *dev_handle,
	unsigned char endpoint, unsigned char *data, int length,
	int *actual_length, unsigned int timeout);

/** \ingroup desc
 * Retrieve a descriptor from the default control pipe.
 * This is a convenience function which formulates the appropriate control
 * message to retrieve the descriptor.
 *
 * \param dev a device handle
 * \param desc_type the descriptor type, see \ref libusb_descriptor_type
 * \param desc_index the index of the descriptor to retrieve
 * \param data output buffer for descriptor
 * \param length size of data buffer
 * \returns number of bytes returned in data, or LIBUSB_ERROR code on failure
 */
static inline int libusb_get_descriptor(libusb_device_handle *dev,
	uint8_t desc_type, uint8_t desc_index, unsigned char *data, int length)
{
	return libusb_control_transfer(dev, LIBUSB_ENDPOINT_IN,
		LIBUSB_REQUEST_GET_DESCRIPTOR, (desc_type << 8) | desc_index, 0, data,
		length, 1000);
}

/** \ingroup desc
 * Retrieve a descriptor from a device.
 * This is a convenience function which formulates the appropriate control
 * message to retrieve the descriptor. The string returned is Unicode, as
 * detailed in the USB specifications.
 *
 * \param dev a device handle
 * \param desc_index the index of the descriptor to retrieve
 * \param langid the language ID for the string descriptor
 * \param data output buffer for descriptor
 * \param length size of data buffer
 * \returns number of bytes returned in data, or LIBUSB_ERROR code on failure
 * \see libusb_get_string_descriptor_ascii()
 */
static inline int libusb_get_string_descriptor(libusb_device_handle *dev,
	uint8_t desc_index, uint16_t langid, unsigned char *data, int length)
{
	return libusb_control_transfer(dev, LIBUSB_ENDPOINT_IN,
		LIBUSB_REQUEST_GET_DESCRIPTOR, (LIBUSB_DT_STRING << 8) | desc_index,
		langid, data, length, 1000);
}

int libusb_get_string_descriptor_ascii(libusb_device_handle *dev,
	uint8_t index, unsigned char *data, int length);

/* polling and timeouts */

int libusb_try_lock_events(libusb_context *ctx);
void libusb_lock_events(libusb_context *ctx);
void libusb_unlock_events(libusb_context *ctx);
int libusb_event_handler_active(libusb_context *ctx);
void libusb_lock_event_waiters(libusb_context *ctx);
void libusb_unlock_event_waiters(libusb_context *ctx);
int libusb_wait_for_event(libusb_context *ctx, struct timeval *tv);

int libusb_handle_events_timeout(libusb_context *ctx, struct timeval *tv);
int libusb_handle_events(libusb_context *ctx);
int libusb_handle_events_locked(libusb_context *ctx, struct timeval *tv);
int libusb_get_next_timeout(libusb_context *ctx, struct timeval *tv);

/** \ingroup poll
 * File descriptor for polling
 */
struct libusb_pollfd {
	/** Numeric file descriptor */
	int fd;

	/** Event flags to poll for from <poll.h>. POLLIN indicates that you
	 * should monitor this file descriptor for becoming ready to read from,
	 * and POLLOUT indicates that you should monitor this file descriptor for
	 * nonblocking write readiness. */
	short events;
};

/** \ingroup poll
 * Callback function, invoked when a new file descriptor should be added
 * to the set of file descriptors monitored for events.
 * \param fd the new file descriptor
 * \param events events to monitor for, see \ref libusb_pollfd for a
 * description
 * \param user_data User data pointer specified in
 * libusb_set_pollfd_notifiers() call
 * \see libusb_set_pollfd_notifiers()
 */
typedef void (*libusb_pollfd_added_cb)(int fd, short events, void *user_data);

/** \ingroup poll
 * Callback function, invoked when a file descriptor should be removed from
 * the set of file descriptors being monitored for events. After returning
 * from this callback, do not use that file descriptor again.
 * \param fd the file descriptor to stop monitoring
 * \param user_data User data pointer specified in
 * libusb_set_pollfd_notifiers() call
 * \see libusb_set_pollfd_notifiers()
 */
typedef void (*libusb_pollfd_removed_cb)(int fd, void *user_data);

const struct libusb_pollfd **libusb_get_pollfds(libusb_context *ctx);
void libusb_set_pollfd_notifiers(libusb_context *ctx,
	libusb_pollfd_added_cb added_cb, libusb_pollfd_removed_cb removed_cb,
	void *user_data);

#ifdef __cplusplus
}
#endif

#endif