src/lib.rs

#![allow(non_camel_case_types)]

pub mod constants;

use self::constants::*;
use libc::{c_char, c_int, c_short, c_uchar, c_uint, c_void, ssize_t, timeval};

#[repr(C)]
pub struct libusb_context {
    __private: c_void,
}

#[repr(C)]
pub struct libusb_device {
    __private: c_void,
}

#[repr(C)]
pub struct libusb_device_handle {
    __private: c_void,
}

#[repr(C)]
pub struct libusb_version {
    pub major: u16,
    pub minor: u16,
    pub micro: u16,
    pub nano: u16,
    pub rc: *const c_char,
    pub describe: *const c_char,
}

#[allow(non_snake_case)]
#[repr(C)]
pub struct libusb_device_descriptor {
    pub bLength: u8,
    pub bDescriptorType: u8,
    pub bcdUSB: u16,
    pub bDeviceClass: u8,
    pub bDeviceSubClass: u8,
    pub bDeviceProtocol: u8,
    pub bMaxPacketSize0: u8,
    pub idVendor: u16,
    pub idProduct: u16,
    pub bcdDevice: u16,
    pub iManufacturer: u8,
    pub iProduct: u8,
    pub iSerialNumber: u8,
    pub bNumConfigurations: u8,
}

#[allow(non_snake_case)]
#[repr(C)]
pub struct libusb_config_descriptor {
    pub bLength: u8,
    pub bDescriptorType: u8,
    pub wTotalLength: u16,
    pub bNumInterfaces: u8,
    pub bConfigurationValue: u8,
    pub iConfiguration: u8,
    pub bmAttributes: u8,
    pub bMaxPower: u8,
    pub interface: *const libusb_interface,
    pub extra: *const c_uchar,
    pub extra_length: c_int,
}

#[repr(C)]
pub struct libusb_interface {
    pub altsetting: *const libusb_interface_descriptor,
    pub num_altsetting: c_int,
}

#[allow(non_snake_case)]
#[repr(C)]
pub struct libusb_interface_descriptor {
    pub bLength: u8,
    pub bDescriptorType: u8,
    pub bInterfaceNumber: u8,
    pub bAlternateSetting: u8,
    pub bNumEndpoints: u8,
    pub bInterfaceClass: u8,
    pub bInterfaceSubClass: u8,
    pub bInterfaceProtocol: u8,
    pub iInterface: u8,
    pub endpoint: *const libusb_endpoint_descriptor,
    pub extra: *const c_uchar,
    pub extra_length: c_int,
}

#[allow(non_snake_case)]
#[repr(C)]
pub struct libusb_endpoint_descriptor {
    pub bLength: u8,
    pub bDescriptorType: u8,
    pub bEndpointAddress: u8,
    pub bmAttributes: u8,
    pub wMaxPacketSize: u16,
    pub bInterval: u8,
    pub bRefresh: u8,
    pub bSynchAddress: u8,
    pub extra: *const c_uchar,
    pub extra_length: c_int,
}

#[repr(C)]
pub struct libusb_iso_packet_descriptor {
    pub length: c_uint,
    pub actual_length: c_uint,
    pub status: c_int,
}

#[allow(non_snake_case)]
#[repr(C)]
pub struct libusb_ss_endpoint_companion_descriptor {
    pub bLength: u8,
    pub bDescriptorType: u8,
    pub bMaxBurst: u8,
    pub bmAttributes: u8,
    pub wBytesPerInterval: u16,
}

#[allow(non_snake_case)]
#[repr(C)]
pub struct libusb_bos_dev_capability_descriptor {
    pub bLength: u8,
    pub bDescriptorType: u8,
    pub bDevCapabilityType: u8,
    pub dev_capability_data: [u8; 0],
}

#[allow(non_snake_case)]
#[repr(C)]
pub struct libusb_bos_descriptor {
    pub bLength: u8,
    pub bDescriptorType: u8,
    pub wTotalLength: u16,
    pub bNumDeviceCaps: u8,
    pub dev_capability: [libusb_bos_dev_capability_descriptor; 0],
}

#[allow(non_snake_case)]
#[repr(C)]
pub struct libusb_usb_2_0_extension_descriptor {
    pub bLength: u8,
    pub bDescriptorType: u8,
    pub bDevCapabilityType: u8,
    pub bmAttributes: u32,
}

#[allow(non_snake_case)]
#[repr(C)]
pub struct libusb_ss_usb_device_capability_descriptor {
    pub bLength: u8,
    pub bDescriptorType: u8,
    pub bDevCapabilityType: u8,
    pub bmAttributes: u8,
    pub wSpeedSupported: u16,
    pub bFunctionalitySupport: u8,
    pub bU1DevExitLat: u8,
    pub bU2DevExitLat: u8,
}

#[allow(non_snake_case)]
#[repr(C)]
pub struct libusb_container_id_descriptor {
    pub bLength: u8,
    pub bDescriptorType: u8,
    pub bDevCapabilityType: u8,
    pub bReserved: u8,
    pub ContainerId: [u8; 16],
}

#[allow(non_snake_case)]
#[repr(C, packed)]
pub struct libusb_control_setup {
    pub bmRequestType: u8,
    pub bRequest: u8,
    pub wValue: u16,
    pub wIndex: u16,
    pub wLength: u16,
}

#[repr(C)]
pub struct libusb_transfer {
    pub dev_handle: *mut libusb_device_handle,
    pub flags: u8,
    pub endpoint: c_uchar,
    pub transfer_type: c_uchar,
    pub timeout: c_uint,
    pub status: c_int,
    pub length: c_int,
    pub actual_length: c_int,
    pub callback: libusb_transfer_cb_fn,
    pub user_data: *mut c_void,
    pub buffer: *mut c_uchar,
    pub num_iso_packets: c_int,
    pub iso_packet_desc: [libusb_iso_packet_descriptor; 0],
}

#[repr(C)]
pub struct libusb_pollfd {
    pub fd: c_int,
    pub events: c_short,
}

pub type libusb_hotplug_callback_handle = c_int;
pub type libusb_hotplug_flag = c_int;
pub type libusb_hotplug_event = c_int;

pub type libusb_log_cb_mode = c_int;

pub type libusb_transfer_cb_fn = extern "system" fn(*mut libusb_transfer);
pub type libusb_pollfd_added_cb = extern "system" fn(c_int, c_short, *mut c_void);
pub type libusb_pollfd_removed_cb = extern "system" fn(c_int, *mut c_void);
pub type libusb_hotplug_callback_fn = extern "system" fn(
    ctx: *mut libusb_context,
    device: *mut libusb_device,
    event: libusb_hotplug_event,
    user_data: *mut c_void,
) -> c_int;

pub type libusb_log_cb = extern "system" fn(context: *mut libusb_context, c_int, *mut c_void);

extern "system" {
    pub fn libusb_get_version() -> *const libusb_version;
    pub fn libusb_has_capability(capability: u32) -> c_int;
    pub fn libusb_error_name(errcode: c_int) -> *const c_char;
    pub fn libusb_setlocale(locale: *const c_char) -> c_int;
    pub fn libusb_strerror(errcode: c_int) -> *const c_char;

    pub fn libusb_init(context: *mut *mut libusb_context) -> c_int;
    pub fn libusb_exit(context: *mut libusb_context);
    pub fn libusb_set_debug(context: *mut libusb_context, level: c_int);
    pub fn libusb_set_log_cb(context: *mut libusb_context, cb: Option<libusb_log_cb>, mode: c_int);

    pub fn libusb_get_device_list(
        context: *mut libusb_context,
        list: *mut *const *mut libusb_device,
    ) -> ssize_t;
    pub fn libusb_free_device_list(list: *const *mut libusb_device, unref_devices: c_int);
    pub fn libusb_get_parent(dev: *mut libusb_device) -> *mut libusb_device;
    pub fn libusb_get_device(dev_handle: *mut libusb_device_handle) -> *mut libusb_device;

    pub fn libusb_ref_device(dev: *mut libusb_device) -> *mut libusb_device;
    pub fn libusb_unref_device(dev: *mut libusb_device);

    pub fn libusb_get_device_descriptor(
        dev: *const libusb_device,
        desc: *mut libusb_device_descriptor,
    ) -> c_int;
    pub fn libusb_get_config_descriptor(
        dev: *const libusb_device,
        index: u8,
        config: *mut *const libusb_config_descriptor,
    ) -> c_int;
    pub fn libusb_get_active_config_descriptor(
        dev: *const libusb_device,
        config: *mut *const libusb_config_descriptor,
    ) -> c_int;
    pub fn libusb_get_config_descriptor_by_value(
        dev: *const libusb_device,
        bConfigurationValue: u8,
        config: *mut *const libusb_config_descriptor,
    ) -> c_int;
    pub fn libusb_free_config_descriptor(config: *const libusb_config_descriptor);

    pub fn libusb_get_bus_number(dev: *const libusb_device) -> u8;
    pub fn libusb_get_port_number(dev: *mut libusb_device) -> u8;
    pub fn libusb_get_port_numbers(
        dev: *mut libusb_device,
        port_numbers: *mut u8,
        port_numbers_len: c_int,
    ) -> c_int;
    pub fn libusb_get_device_address(dev: *const libusb_device) -> u8;
    pub fn libusb_get_device_speed(dev: *const libusb_device) -> c_int;
    pub fn libusb_get_max_packet_size(dev: *const libusb_device, endpoint: c_uchar) -> c_int;
    pub fn libusb_get_max_iso_packet_size(dev: *const libusb_device, endpoint: c_uchar) -> c_int;

    pub fn libusb_wrap_sys_device(
        context: *mut libusb_context,
        sys_dev: *mut c_int,
        handle: *mut *mut libusb_device_handle,
    ) -> c_int;
    pub fn libusb_open(dev: *const libusb_device, handle: *mut *mut libusb_device_handle) -> c_int;
    pub fn libusb_close(dev_handle: *mut libusb_device_handle);
    pub fn libusb_open_device_with_vid_pid(
        context: *mut libusb_context,
        vendor_id: u16,
        product_id: u16,
    ) -> *mut libusb_device_handle;
    pub fn libusb_reset_device(dev_handle: *mut libusb_device_handle) -> c_int;
    pub fn libusb_clear_halt(dev_handle: *mut libusb_device_handle, endpoint: c_uchar) -> c_int;
    pub fn libusb_alloc_streams(
        dev_handle: *mut libusb_device_handle,
        num_streams: u32,
        endpoints: *mut c_uchar,
        num_endpoints: c_int,
    ) -> c_int;
    pub fn libusb_free_streams(
        dev_handle: *mut libusb_device_handle,
        endpoints: *mut c_uchar,
        num_endpoints: c_int,
    ) -> c_int;
    pub fn libusb_get_string_descriptor_ascii(
        dev_handle: *mut libusb_device_handle,
        desc_index: u8,
        data: *mut c_uchar,
        length: c_int,
    ) -> c_int;

    pub fn libusb_get_configuration(
        dev_handle: *mut libusb_device_handle,
        config: *mut c_int,
    ) -> c_int;
    pub fn libusb_set_configuration(dev_handle: *mut libusb_device_handle, config: c_int) -> c_int;

    pub fn libusb_get_ss_endpoint_companion_descriptor(
        context: *mut libusb_context,
        endpoint: *const libusb_endpoint_descriptor,
        ep_comp: *mut *const libusb_ss_endpoint_companion_descriptor,
    ) -> c_int;
    pub fn libusb_free_ss_endpoint_companion_descriptor(
        ep_comp: *mut libusb_ss_endpoint_companion_descriptor,
    );
    pub fn libusb_get_bos_descriptor(
        dev_handle: *mut libusb_device_handle,
        bos: *mut *const libusb_bos_descriptor,
    ) -> c_int;
    pub fn libusb_free_bos_descriptor(bos: *mut libusb_bos_descriptor);
    pub fn libusb_get_usb_2_0_extension_descriptor(
        context: *mut libusb_context,
        dev_cap: *mut libusb_bos_dev_capability_descriptor,
        usb_2_0_extension: *mut *const libusb_usb_2_0_extension_descriptor,
    ) -> c_int;
    pub fn libusb_free_usb_2_0_extension_descriptor(
        usb_2_0_extension: *mut libusb_usb_2_0_extension_descriptor,
    );
    pub fn libusb_get_ss_usb_device_capability_descriptor(
        context: *mut libusb_context,
        dev_cap: *mut libusb_bos_dev_capability_descriptor,
        ss_usb_device_cap: *mut *const libusb_ss_usb_device_capability_descriptor,
    ) -> c_int;
    pub fn libusb_free_ss_usb_device_capability_descriptor(
        ss_usb_device_cap: *mut libusb_ss_usb_device_capability_descriptor,
    );
    pub fn libusb_get_container_id_descriptor(
        context: *mut libusb_context,
        dev_cap: *mut libusb_bos_dev_capability_descriptor,
        container_id: *mut *const libusb_container_id_descriptor,
    ) -> c_int;
    pub fn libusb_free_container_id_descriptor(container_id: *mut libusb_container_id_descriptor);

    pub fn libusb_set_auto_detach_kernel_driver(
        dev_handle: *mut libusb_device_handle,
        enable: c_int,
    ) -> c_int;
    pub fn libusb_kernel_driver_active(
        dev_handle: *mut libusb_device_handle,
        interface_number: c_int,
    ) -> c_int;
    pub fn libusb_detach_kernel_driver(
        dev_handle: *mut libusb_device_handle,
        interface_number: c_int,
    ) -> c_int;
    pub fn libusb_attach_kernel_driver(
        dev_handle: *mut libusb_device_handle,
        interface_number: c_int,
    ) -> c_int;

    pub fn libusb_claim_interface(
        dev_handle: *mut libusb_device_handle,
        interface_number: c_int,
    ) -> c_int;
    pub fn libusb_release_interface(
        dev_handle: *mut libusb_device_handle,
        interface_number: c_int,
    ) -> c_int;
    pub fn libusb_set_interface_alt_setting(
        dev_handle: *mut libusb_device_handle,
        interface_number: c_int,
        alternate_setting: c_int,
    ) -> c_int;

    pub fn libusb_interrupt_transfer(
        dev_handle: *mut libusb_device_handle,
        endpoint: c_uchar,
        data: *mut c_uchar,
        length: c_int,
        transferred: *mut c_int,
        timeout: c_uint,
    ) -> c_int;
    pub fn libusb_bulk_transfer(
        dev_handle: *mut libusb_device_handle,
        endpoint: c_uchar,
        data: *mut c_uchar,
        length: c_int,
        transferred: *mut c_int,
        timeout: c_uint,
    ) -> c_int;
    pub fn libusb_control_transfer(
        dev_handle: *mut libusb_device_handle,
        request_type: u8,
        request: u8,
        value: u16,
        index: u16,
        data: *mut c_uchar,
        length: u16,
        timeout: c_uint,
    ) -> c_int;

    pub fn libusb_alloc_transfer(iso_packets: c_int) -> *mut libusb_transfer;
    pub fn libusb_submit_transfer(transfer: *mut libusb_transfer) -> c_int;
    pub fn libusb_cancel_transfer(transfer: *mut libusb_transfer) -> c_int;
    pub fn libusb_free_transfer(transfer: *mut libusb_transfer);
    pub fn libusb_transfer_set_stream_id(transfer: *mut libusb_transfer, stream_id: u32);
    pub fn libusb_transfer_get_stream_id(transfer: *mut libusb_transfer) -> u32;

    pub fn libusb_handle_events(context: *mut libusb_context) -> c_int;
    pub fn libusb_handle_events_timeout(context: *mut libusb_context, tv: *const timeval) -> c_int;
    pub fn libusb_handle_events_completed(
        context: *mut libusb_context,
        completed: *mut c_int,
    ) -> c_int;
    pub fn libusb_handle_events_timeout_completed(
        context: *mut libusb_context,
        tv: *const timeval,
        completed: *mut c_int,
    ) -> c_int;
    pub fn libusb_handle_events_locked(context: *mut libusb_context, tv: *const timeval) -> c_int;
    pub fn libusb_interrupt_event_handler(context: *mut libusb_context);

    pub fn libusb_try_lock_events(context: *mut libusb_context) -> c_int;
    pub fn libusb_lock_events(context: *mut libusb_context);
    pub fn libusb_unlock_events(context: *mut libusb_context);
    pub fn libusb_event_handling_ok(context: *mut libusb_context) -> c_int;
    pub fn libusb_event_handler_active(context: *mut libusb_context) -> c_int;
    pub fn libusb_lock_event_waiters(context: *mut libusb_context);
    pub fn libusb_unlock_event_waiters(context: *mut libusb_context);
    pub fn libusb_wait_for_event(context: *mut libusb_context, tv: *const timeval) -> c_int;

    pub fn libusb_pollfds_handle_timeouts(context: *mut libusb_context) -> c_int;
    pub fn libusb_get_next_timeout(context: *mut libusb_context, tv: *mut timeval) -> c_int;
    pub fn libusb_get_pollfds(context: *mut libusb_context) -> *const *mut libusb_pollfd;
    pub fn libusb_set_pollfd_notifiers(
        context: *mut libusb_context,
        added_cb: Option<libusb_pollfd_added_cb>,
        removed_cb: Option<libusb_pollfd_removed_cb>,
        user_data: *mut c_void,
    );
    pub fn libusb_free_pollfds(pollfds: *const *mut libusb_pollfd);
    pub fn libusb_hotplug_register_callback(
        ctx: *mut libusb_context,
        events: c_int,
        flags: c_int,
        vendor_id: c_int,
        product_id: c_int,
        dev_class: c_int,
        cb_fn: libusb_hotplug_callback_fn,
        user_data: *mut c_void,
        callback_handle: *mut libusb_hotplug_callback_handle,
    ) -> c_int;
    pub fn libusb_hotplug_deregister_callback(
        ctx: *mut libusb_context,
        callback_handle: libusb_hotplug_callback_handle,
    );

    pub fn libusb_hotplug_get_user_data(
        ctx: *mut libusb_context,
        callback_handle: libusb_hotplug_callback_handle,
    ) -> *mut c_void;
}

// As libusb_set_option is a variatic function, it must use "C"
// calling conventions
extern "C" {
    pub fn libusb_set_option(ctx: *mut libusb_context, option: u32, ...) -> c_int;
}

// defined as static inline in libusb.h
#[inline]
pub unsafe fn libusb_get_string_descriptor(
    dev_handle: *mut libusb_device_handle,
    desc_index: u8,
    langid: u16,
    data: *mut c_uchar,
    length: c_int,
) -> c_int {
    libusb_control_transfer(
        dev_handle,
        LIBUSB_ENDPOINT_IN,
        LIBUSB_REQUEST_GET_DESCRIPTOR,
        u16::from(LIBUSB_DT_STRING) << 8 | u16::from(desc_index),
        langid,
        data,
        length as u16,
        1000,
    )
}

// defined as static inline in libusb.h
#[inline]
pub unsafe fn libusb_get_descriptor(
    dev_handle: *mut libusb_device_handle,
    desc_type: u8,
    desc_index: u8,
    langid: u16,
    data: *mut c_uchar,
    length: c_int,
) -> c_int {
    libusb_control_transfer(
        dev_handle,
        LIBUSB_ENDPOINT_IN,
        LIBUSB_REQUEST_GET_DESCRIPTOR,
        u16::from(desc_type) << 8 | u16::from(desc_index),
        langid,
        data,
        length as u16,
        1000,
    )
}

#[inline]
pub unsafe fn libusb_control_transfer_get_data(transfer: *mut libusb_transfer) -> *mut c_uchar {
    (*transfer).buffer.add(constants::LIBUSB_CONTROL_SETUP_SIZE)
}

#[inline]
pub unsafe fn libusb_control_transfer_get_setup(
    transfer: *mut libusb_transfer,
) -> *mut libusb_control_setup {
    (*transfer).buffer as *mut _
}

#[allow(non_snake_case)]
#[inline]
pub unsafe fn libusb_fill_control_setup(
    buffer: *mut c_uchar,
    bmRequestType: u8,
    bRequest: u8,
    wValue: u16,
    wIndex: u16,
    wLength: u16,
) {
    let setup: *mut libusb_control_setup = buffer as *mut _;
    (*setup).bmRequestType = bmRequestType;
    (*setup).bRequest = bRequest;
    (*setup).wValue = wValue.to_le();
    (*setup).wIndex = wIndex.to_le();
    (*setup).wLength = wLength.to_le();
}

#[inline]
pub unsafe fn libusb_fill_control_transfer(
    transfer: *mut libusb_transfer,
    dev_handle: *mut libusb_device_handle,
    buffer: *mut u8,
    callback: libusb_transfer_cb_fn,
    user_data: *mut c_void,
    timeout: c_uint,
) {
    let setup: *mut libusb_control_setup = buffer as *mut c_void as *mut libusb_control_setup;

    (*transfer).dev_handle = dev_handle;
    (*transfer).endpoint = 0;
    (*transfer).transfer_type = LIBUSB_TRANSFER_TYPE_CONTROL;
    (*transfer).timeout = timeout;
    (*transfer).buffer = buffer;
    if !buffer.is_null() {
        (*transfer).length =
            (constants::LIBUSB_CONTROL_SETUP_SIZE as u16 + u16::from_le((*setup).wLength)).into();
    }
    (*transfer).user_data = user_data;
    (*transfer).callback = callback;
}

#[inline]
pub unsafe fn libusb_fill_bulk_transfer(
    transfer: *mut libusb_transfer,
    dev_handle: *mut libusb_device_handle,
    endpoint: u8,
    buffer: *mut u8,
    length: c_int,
    callback: libusb_transfer_cb_fn,
    user_data: *mut c_void,
    timeout: c_uint,
) {
    (*transfer).dev_handle = dev_handle;
    (*transfer).endpoint = endpoint;
    (*transfer).transfer_type = LIBUSB_TRANSFER_TYPE_BULK;
    (*transfer).timeout = timeout;
    (*transfer).buffer = buffer;
    (*transfer).length = length;
    (*transfer).user_data = user_data;
    (*transfer).callback = callback;
}

#[inline]
pub unsafe fn libusb_fill_bulk_stream_transfer(
    transfer: *mut libusb_transfer,
    dev_handle: *mut libusb_device_handle,
    endpoint: u8,
    stream_id: u32,
    buffer: *mut u8,
    length: c_int,
    callback: libusb_transfer_cb_fn,
    user_data: *mut c_void,
    timeout: c_uint,
) {
    libusb_fill_bulk_transfer(
        transfer, dev_handle, endpoint, buffer, length, callback, user_data, timeout,
    );
    (*transfer).transfer_type = LIBUSB_TRANSFER_TYPE_BULK_STREAM;
    libusb_transfer_set_stream_id(transfer, stream_id);
}

#[inline]
pub unsafe fn libusb_fill_interrupt_transfer(
    transfer: *mut libusb_transfer,
    dev_handle: *mut libusb_device_handle,
    endpoint: u8,
    buffer: *mut u8,
    length: c_int,
    callback: libusb_transfer_cb_fn,
    user_data: *mut c_void,
    timeout: c_uint,
) {
    (*transfer).dev_handle = dev_handle;
    (*transfer).endpoint = endpoint;
    (*transfer).transfer_type = LIBUSB_TRANSFER_TYPE_INTERRUPT;
    (*transfer).timeout = timeout;
    (*transfer).buffer = buffer;
    (*transfer).length = length;
    (*transfer).user_data = user_data;
    (*transfer).callback = callback;
}

#[inline]
pub unsafe fn libusb_fill_iso_transfer(
    transfer: *mut libusb_transfer,
    dev_handle: *mut libusb_device_handle,
    endpoint: u8,
    buffer: *mut u8,
    length: c_int,
    num_iso_packets: c_int,
    callback: libusb_transfer_cb_fn,
    user_data: *mut c_void,
    timeout: c_uint,
) {
    (*transfer).dev_handle = dev_handle;
    (*transfer).endpoint = endpoint;
    (*transfer).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;
}

#[inline]
pub unsafe fn libusb_set_iso_packet_lengths(transfer: *mut libusb_transfer, length: c_uint) {
    for i in 0..(*transfer).num_iso_packets {
        (*(*transfer).iso_packet_desc.as_mut_ptr().add(i as usize)).length = length;
    }
}

#[inline]
pub unsafe fn libusb_get_iso_packet_buffer(
    transfer: *mut libusb_transfer,
    packet: c_uint,
) -> *mut c_uchar {
    if packet as c_int >= (*transfer).num_iso_packets {
        return std::ptr::null_mut();
    }
    let mut offset = 0;
    for i in 0..packet {
        offset += (*(*transfer).iso_packet_desc.as_mut_ptr().add(i as usize)).length;
    }

    (*transfer).buffer.add(offset as usize)
}

#[inline]
pub unsafe fn libusb_get_iso_packet_buffer_simple(
    transfer: *mut libusb_transfer,
    packet: c_uint,
) -> *mut c_uchar {
    if packet as c_int >= (*transfer).num_iso_packets {
        return std::ptr::null_mut();
    }

    (*transfer)
        .buffer
        .add(((*(*transfer).iso_packet_desc.as_mut_ptr().add(0)).length * packet) as usize)
}