# Copyright (C) 2010-2018  Vincent Pelletier <plr.vincent@gmail.com>
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

# pylint: disable=invalid-name, too-few-public-methods, too-many-arguments
# pylint: disable=missing-docstring
"""
Python ctypes bindings for libusb-1.0.

You should not need to import this if you use usb1 module.

Declares all constants, data structures and exported symbols.
Locates and loads libusb1 dynamic library.
"""
from ctypes import (
    Structure, LittleEndianStructure,
    CFUNCTYPE, POINTER, addressof, sizeof, cast,
    c_short, c_int, c_uint, c_size_t, c_long,
    c_uint8, c_uint16, c_uint32,
    c_void_p, c_char_p, py_object, pointer, c_char,
    c_ssize_t, CDLL
)
import ctypes.util
import platform
import os.path
import sys

class Enum(object):
    def __init__(self, member_dict, scope_dict=None):
        if scope_dict is None:
            # Affect caller's locals, not this module's.
            # pylint: disable=protected-access
            scope_dict = sys._getframe(1).f_locals
            # pylint: enable=protected-access
        forward_dict = {}
        reverse_dict = {}
        next_value = 0
        for name, value in member_dict.items():
            if value is None:
                value = next_value
                next_value += 1
            forward_dict[name] = value
            if value in reverse_dict:
                raise ValueError('Multiple names for value %r: %r, %r' % (
                    value, reverse_dict[value], name
                ))
            reverse_dict[value] = name
            scope_dict[name] = value
        self.forward_dict = forward_dict
        self.reverse_dict = reverse_dict

    def __call__(self, value):
        return self.reverse_dict[value]

    def get(self, value, default=None):
        return self.reverse_dict.get(value, default)

def buffer_at(address, length):
    """
    Simular to ctypes.string_at, but zero-copy and requires an integer address.
    """
    return bytearray((c_char * length).from_address(address))

_desc_type_dict = {
    'b': c_uint8,
    'bcd': c_uint16,
    'bm': c_uint8,
    'dw': c_uint32,
    'i': c_uint8,
    'id': c_uint16,
    'w': c_uint16,
}

def newStruct(field_name_list):
    """
    Create a ctype structure class based on USB standard field naming
    (type-prefixed).
    """
    field_list = []
    append = field_list.append
    for field in field_name_list:
        type_prefix = ''
        for char in field:
            if not char.islower():
                break
            type_prefix += char
        append((field, _desc_type_dict[type_prefix]))
    result = type('some_descriptor', (LittleEndianStructure, ), {})
    # Not using type()'s 3rd param to initialise class, as per ctypes
    # documentation:
    #   _pack_ must already be defined when _fields_ is assigned, otherwise it
    #   will have no effect.
    # pylint: disable=protected-access
    result._pack_ = 1
    result._fields_ = field_list
    # pylint: enable=protected-access
    return result

def newDescriptor(field_name_list):
    """
    Create a USB descriptor ctype structure, ie starting with bLength and
    bDescriptorType fields.

    See newStruct().
    """
    return newStruct(['bLength', 'bDescriptorType'] + list(field_name_list))

class USBError(Exception):
    value = None

    def __init__(self, value=None):
        Exception.__init__(self)
        if value is not None:
            self.value = value

    def __str__(self):
        return '%s [%s]' % (libusb_error.get(self.value, 'Unknown error'),
                            self.value)

c_uchar = c_uint8
c_int_p = POINTER(c_int)

LITTLE_ENDIAN = sys.byteorder == 'little'

class timeval(Structure):
    _fields_ = [('tv_sec', c_long),
                ('tv_usec', c_long)]
timeval_p = POINTER(timeval)

def _loadLibrary():
    system = platform.system()
    if system == 'Windows':
        dll_loader = ctypes.WinDLL
        suffix = '.dll'
    else:
        dll_loader = ctypes.CDLL
        suffix = system == 'Darwin' and '.dylib' or '.so'
    filename = 'libusb-1.0' + suffix
    # If this is a binary wheel, use the integrated libusb unconditionally.
    # To use the libusb from the Python installation or the OS, install from sdist:
    #   > pip install --no-binary :all: libusb1
    if os.path.exists(os.path.join(os.path.dirname(__file__), filename)):
        filename = os.path.join(os.path.dirname(__file__), filename)
    try:
        return dll_loader(filename, use_errno=True, use_last_error=True)
    except OSError:
        libusb_path = None
        base_name = 'usb-1.0'
        if 'FreeBSD' in system:
            # libusb.so.2 on FreeBSD: load('libusb.so') would work fine, but...
            # libusb.so.2debian on Debian GNU/kFreeBSD: here it wouldn't work.
            # So use find_library instead.
            base_name = 'usb'
        elif system == 'Darwin':
            for libusb_path in (
                    # macport standard path
                    '/opt/local/lib/libusb-1.0.dylib',
                    # fink standard path
                    '/sw/lib/libusb-1.0.dylib',
                ):
                if os.path.exists(libusb_path):
                    break
            else:
                libusb_path = None
        if libusb_path is None:
            libusb_path = ctypes.util.find_library(base_name)
            if libusb_path is None:
                raise
        return dll_loader(libusb_path, use_errno=True, use_last_error=True)

libusb = _loadLibrary()

# libusb.h
def bswap16(x):
    return ((x & 0xff) << 8) | (x >> 8)

if LITTLE_ENDIAN:
    def libusb_cpu_to_le16(x):
        return x
    def libusb_le16_to_cpu(x):
        return x
else:
    libusb_cpu_to_le16 = bswap16
    libusb_le16_to_cpu = bswap16

# standard USB stuff

# Device and/or Interface Class codes
libusb_class_code = Enum({
    # In the context of a device descriptor,
    # this bDeviceClass value indicates that each interface specifies its
    # own class information and all interfaces operate independently.
    'LIBUSB_CLASS_PER_INTERFACE': 0,
    # Audio class
    'LIBUSB_CLASS_AUDIO': 1,
    # Communications class
    'LIBUSB_CLASS_COMM': 2,
    # Human Interface Device class
    'LIBUSB_CLASS_HID': 3,
    # Physical
    'LIBUSB_CLASS_PHYSICAL': 5,
    # Printer class
    'LIBUSB_CLASS_PRINTER': 7,
    # Picture transfer protocol class
    'LIBUSB_CLASS_PTP': 6,
    # Mass storage class
    'LIBUSB_CLASS_MASS_STORAGE': 8,
    # Hub class
    'LIBUSB_CLASS_HUB': 9,
    # Data class
    'LIBUSB_CLASS_DATA': 10,
    # Smart Card
    'LIBUSB_CLASS_SMART_CARD': 0x0b,
    # Content Security
    'LIBUSB_CLASS_CONTENT_SECURITY': 0x0d,
    # Video
    'LIBUSB_CLASS_VIDEO': 0x0e,
    # Personal Healthcare
    'LIBUSB_CLASS_PERSONAL_HEALTHCARE': 0x0f,
    # Diagnostic Device
    'LIBUSB_CLASS_DIAGNOSTIC_DEVICE': 0xdc,
    # Wireless class
    'LIBUSB_CLASS_WIRELESS': 0xe0,
    # Application class
    'LIBUSB_CLASS_APPLICATION': 0xfe,
    # Class is vendor-specific
    'LIBUSB_CLASS_VENDOR_SPEC': 0xff
})
# pylint: disable=undefined-variable
LIBUSB_CLASS_IMAGE = LIBUSB_CLASS_PTP
# pylint: enable=undefined-variable

# Descriptor types as defined by the USB specification.
libusb_descriptor_type = Enum({
    # Device descriptor. See libusb_device_descriptor.
    'LIBUSB_DT_DEVICE': 0x01,
    # Configuration descriptor. See libusb_config_descriptor.
    'LIBUSB_DT_CONFIG': 0x02,
    # String descriptor
    'LIBUSB_DT_STRING': 0x03,
    # Interface descriptor. See libusb_interface_descriptor.
    'LIBUSB_DT_INTERFACE': 0x04,
    # Endpoint descriptor. See libusb_endpoint_descriptor.
    'LIBUSB_DT_ENDPOINT': 0x05,
    # HID descriptor
    'LIBUSB_DT_HID': 0x21,
    # HID report descriptor
    'LIBUSB_DT_REPORT': 0x22,
    # Physical descriptor
    'LIBUSB_DT_PHYSICAL': 0x23,
    # Hub descriptor
    'LIBUSB_DT_HUB': 0x29,
})

# Descriptor sizes per descriptor type
LIBUSB_DT_DEVICE_SIZE = 18
LIBUSB_DT_CONFIG_SIZE = 9
LIBUSB_DT_INTERFACE_SIZE = 9
LIBUSB_DT_ENDPOINT_SIZE = 7
LIBUSB_DT_ENDPOINT_AUDIO_SIZE = 9 # Audio extension
LIBUSB_DT_HUB_NONVAR_SIZE = 7

LIBUSB_ENDPOINT_ADDRESS_MASK = 0x0f # in bEndpointAddress
LIBUSB_ENDPOINT_DIR_MASK = 0x80
# BBB
USB_ENDPOINT_ADDRESS_MASK = LIBUSB_ENDPOINT_ADDRESS_MASK
USB_ENDPOINT_DIR_MASK = LIBUSB_ENDPOINT_DIR_MASK

# Endpoint direction. Values for bit 7 of the endpoint address scheme.
libusb_endpoint_direction = Enum({
    # In: device-to-host
    'LIBUSB_ENDPOINT_IN': 0x80,
    # Out: host-to-device
    'LIBUSB_ENDPOINT_OUT': 0x00
})

LIBUSB_TRANSFER_TYPE_MASK = 0x03 # in bmAttributes

# Endpoint transfer type. Values for bits 0:1 of the endpoint attributes field.
libusb_transfer_type = Enum({
    # Control endpoint
    'LIBUSB_TRANSFER_TYPE_CONTROL': 0,
    # Isochronous endpoint
    'LIBUSB_TRANSFER_TYPE_ISOCHRONOUS': 1,
    # Bulk endpoint
    'LIBUSB_TRANSFER_TYPE_BULK': 2,
    # Interrupt endpoint
    'LIBUSB_TRANSFER_TYPE_INTERRUPT': 3,
})

# Standard requests, as defined in table 9-3 of the USB2 specifications
libusb_standard_request = Enum({
    # Request status of the specific recipient
    'LIBUSB_REQUEST_GET_STATUS': 0x00,
    # Clear or disable a specific feature
    'LIBUSB_REQUEST_CLEAR_FEATURE': 0x01,
    # 0x02 is reserved
    # Set or enable a specific feature
    'LIBUSB_REQUEST_SET_FEATURE': 0x03,
    # 0x04 is reserved
    # Set device address for all future accesses
    'LIBUSB_REQUEST_SET_ADDRESS': 0x05,
    # Get the specified descriptor
    'LIBUSB_REQUEST_GET_DESCRIPTOR': 0x06,
    # Used to update existing descriptors or add new descriptors
    'LIBUSB_REQUEST_SET_DESCRIPTOR': 0x07,
    # Get the current device configuration value
    'LIBUSB_REQUEST_GET_CONFIGURATION': 0x08,
    # Set device configuration
    'LIBUSB_REQUEST_SET_CONFIGURATION': 0x09,
    # Return the selected alternate setting for the specified interface
    'LIBUSB_REQUEST_GET_INTERFACE': 0x0a,
    # Select an alternate interface for the specified interface
    'LIBUSB_REQUEST_SET_INTERFACE': 0x0b,
    # Set then report an endpoint's synchronization frame
    'LIBUSB_REQUEST_SYNCH_FRAME': 0x0c,
})

# Request type bits of the bmRequestType field in control transfers.
libusb_request_type = Enum({
    # Standard
    'LIBUSB_REQUEST_TYPE_STANDARD': (0x00 << 5),
    # Class
    'LIBUSB_REQUEST_TYPE_CLASS': (0x01 << 5),
    # Vendor
    'LIBUSB_REQUEST_TYPE_VENDOR': (0x02 << 5),
    # Reserved
    'LIBUSB_REQUEST_TYPE_RESERVED': (0x03 << 5),
})

# BBB
# pylint: disable=bad-whitespace,undefined-variable
LIBUSB_TYPE_STANDARD = LIBUSB_REQUEST_TYPE_STANDARD
LIBUSB_TYPE_CLASS    = LIBUSB_REQUEST_TYPE_CLASS
LIBUSB_TYPE_VENDOR   = LIBUSB_REQUEST_TYPE_VENDOR
LIBUSB_TYPE_RESERVED = LIBUSB_REQUEST_TYPE_RESERVED
# pylint: enable=bad-whitespace,undefined-variable

# Recipient bits of the bmRequestType field in control transfers. Values 4
# through 31 are reserved.
libusb_request_recipient = Enum({
    # Device
    'LIBUSB_RECIPIENT_DEVICE': 0x00,
    # Interface
    'LIBUSB_RECIPIENT_INTERFACE': 0x01,
    # Endpoint
    'LIBUSB_RECIPIENT_ENDPOINT': 0x02,
    # Other
    'LIBUSB_RECIPIENT_OTHER': 0x03,
})

LIBUSB_ISO_SYNC_TYPE_MASK = 0x0c

# Synchronization type for isochronous endpoints. Values for bits 2:3 of the
# bmAttributes field in libusb_endpoint_descriptor.
libusb_iso_sync_type = Enum({
    # No synchronization
    'LIBUSB_ISO_SYNC_TYPE_NONE': 0,
    # Asynchronous
    'LIBUSB_ISO_SYNC_TYPE_ASYNC': 1,
    # Adaptive
    'LIBUSB_ISO_SYNC_TYPE_ADAPTIVE': 2,
    # Synchronous
    'LIBUSB_ISO_SYNC_TYPE_SYNC': 3,
})

LIBUSB_ISO_USAGE_TYPE_MASK = 0x30

# Usage type for isochronous endpoints. Values for bits 4:5 of the
# bmAttributes field in libusb_endpoint_descriptor.
libusb_iso_usage_type = Enum({
    # Data endpoint
    'LIBUSB_ISO_USAGE_TYPE_DATA': 0,
    # Feedback endpoint
    'LIBUSB_ISO_USAGE_TYPE_FEEDBACK': 1,
    # Implicit feedback Data endpoint
    'LIBUSB_ISO_USAGE_TYPE_IMPLICIT': 2,
})

# A structure representing the standard USB device descriptor. This
# descriptor is documented in section 9.6.1 of the USB 2.0 specification.
# All multiple-byte fields are represented in host-endian format.
class libusb_device_descriptor(Structure):
    _fields_ = [
        # Size of this descriptor (in bytes)
        ('bLength', c_uint8),
        # Descriptor type. Will have value LIBUSB_DT_DEVICE in this
        # context.
        ('bDescriptorType', c_uint8),
        # USB specification release number in binary-coded decimal. A
        # value of 0x0200 indicates USB 2.0, 0x0110 indicates USB 1.1,
        # etc.
        ('bcdUSB', c_uint16),
        # USB-IF class code for the device. See libusb_class_code.
        ('bDeviceClass', c_uint8),
        # USB-IF subclass code for the device, qualified by the
        # bDeviceClass value
        ('bDeviceSubClass', c_uint8),
        # USB-IF protocol code for the device, qualified by the
        # bDeviceClass and bDeviceSubClass values
        ('bDeviceProtocol', c_uint8),
        # Maximum packet size for endpoint 0
        ('bMaxPacketSize0', c_uint8),
        # USB-IF vendor ID
        ('idVendor', c_uint16),
        # USB-IF product ID
        ('idProduct', c_uint16),
        # Device release number in binary-coded decimal
        ('bcdDevice', c_uint16),
        # Index of string descriptor describing manufacturer
        ('iManufacturer', c_uint8),
        # Index of string descriptor describing product
        ('iProduct', c_uint8),
        # Index of string descriptor containing device serial number
        ('iSerialNumber', c_uint8),
        # Number of possible configurations
        ('bNumConfigurations', c_uint8)]
libusb_device_descriptor_p = POINTER(libusb_device_descriptor)

class libusb_endpoint_descriptor(Structure):
    _fields_ = [
        ('bLength', c_uint8),
        ('bDescriptorType', c_uint8),
        ('bEndpointAddress', c_uint8),
        ('bmAttributes', c_uint8),
        ('wMaxPacketSize', c_uint16),
        ('bInterval', c_uint8),
        ('bRefresh', c_uint8),
        ('bSynchAddress', c_uint8),
        ('extra', c_void_p),
        ('extra_length', c_int)]
libusb_endpoint_descriptor_p = POINTER(libusb_endpoint_descriptor)

class libusb_interface_descriptor(Structure):
    _fields_ = [
        ('bLength', c_uint8),
        ('bDescriptorType', c_uint8),
        ('bInterfaceNumber', c_uint8),
        ('bAlternateSetting', c_uint8),
        ('bNumEndpoints', c_uint8),
        ('bInterfaceClass', c_uint8),
        ('bInterfaceSubClass', c_uint8),
        ('bInterfaceProtocol', c_uint8),
        ('iInterface', c_uint8),
        ('endpoint', libusb_endpoint_descriptor_p),
        ('extra', c_void_p),
        ('extra_length', c_int)]
libusb_interface_descriptor_p = POINTER(libusb_interface_descriptor)

class libusb_interface(Structure):
    _fields_ = [('altsetting', libusb_interface_descriptor_p),
                ('num_altsetting', c_int)]
libusb_interface_p = POINTER(libusb_interface)

class libusb_config_descriptor(Structure):
    _fields_ = [
        ('bLength', c_uint8),
        ('bDescriptorType', c_uint8),
        ('wTotalLength', c_uint16),
        ('bNumInterfaces', c_uint8),
        ('bConfigurationValue', c_uint8),
        ('iConfiguration', c_uint8),
        ('bmAttributes', c_uint8),
        ('MaxPower', c_uint8),
        ('interface', libusb_interface_p),
        ('extra', c_void_p),
        ('extra_length', c_int)]
libusb_config_descriptor_p = POINTER(libusb_config_descriptor)
libusb_config_descriptor_p_p = POINTER(libusb_config_descriptor_p)

class libusb_control_setup(Structure):
    _fields_ = [
        ('bmRequestType', c_uint8),
        ('bRequest', c_uint8),
        ('wValue', c_uint16),
        ('wIndex', c_uint16),
        ('wLength', c_uint16)]
libusb_control_setup_p = POINTER(libusb_control_setup)

LIBUSB_CONTROL_SETUP_SIZE = sizeof(libusb_control_setup)

# Structure representing a libusb session. The concept of individual libusb
# sessions allows for your program to use two libraries (or dynamically
# load two modules) which both independently use libusb. This will prevent
# interference between the individual libusb users - for example
# libusb_set_debug() will not affect the other user of the library, and
# libusb_exit() will not destroy resources that the other user is still
# using.
#
# Sessions are created by libusb_init() and destroyed through libusb_exit().
# If your application is guaranteed to only ever include a single libusb
# user (i.e. you), you do not have to worry about contexts: pass NULL in
# every function call where a context is required. The default context
# will be used.
#
# For more information, see \ref contexts.
class libusb_context(Structure):
    pass
libusb_context_p = POINTER(libusb_context)
libusb_context_p_p = POINTER(libusb_context_p)

# Structure representing a USB device detected on the system. This is an
# opaque type for which you are only ever provided with a pointer, usually
# originating from libusb_get_device_list().
#
# Certain operations can be performed on a device, but in order to do any
# I/O you will have to first obtain a device handle using libusb_open().
#
# Devices are reference counted with libusb_device_ref() and
# libusb_device_unref(), and are freed when the reference count reaches 0.
# New devices presented by libusb_get_device_list() have a reference count of
# 1, and libusb_free_device_list() can optionally decrease the reference count
# on all devices in the list. libusb_open() adds another reference which is
# later destroyed by libusb_close().
class libusb_device(Structure):
    pass
libusb_device_p = POINTER(libusb_device)
libusb_device_p_p = POINTER(libusb_device_p)
libusb_device_p_p_p = POINTER(libusb_device_p_p)

# Structure representing a handle on a USB device. This is an opaque type for
# which you are only ever provided with a pointer, usually originating from
# libusb_open().
#
# A device handle is used to perform I/O and other operations. When finished
# with a device handle, you should call libusb_close().
class libusb_device_handle(Structure):
    pass
libusb_device_handle_p = POINTER(libusb_device_handle)
libusb_device_handle_p_p = POINTER(libusb_device_handle_p)

class libusb_version(Structure):
    _fields_ = [
        ('major', c_uint16),
        ('minor', c_uint16),
        ('micro', c_uint16),
        ('nano', c_uint16),
        ('rc', c_char_p),
        ('describe', c_char_p),
    ]

libusb_speed = Enum({
    # The OS doesn't report or know the device speed.
    'LIBUSB_SPEED_UNKNOWN': 0,
    # The device is operating at low speed (1.5MBit/s).
    'LIBUSB_SPEED_LOW': 1,
    # The device is operating at full speed (12MBit/s).
    'LIBUSB_SPEED_FULL': 2,
    # The device is operating at high speed (480MBit/s).
    'LIBUSB_SPEED_HIGH': 3,
    # The device is operating at super speed (5000MBit/s).
    'LIBUSB_SPEED_SUPER': 4,
})

libusb_supported_speed = Enum({
    # Low speed operation supported (1.5MBit/s).
    'LIBUSB_LOW_SPEED_OPERATION': 1,
    # Full speed operation supported (12MBit/s).
    'LIBUSB_FULL_SPEED_OPERATION': 2,
    # High speed operation supported (480MBit/s).
    'LIBUSB_HIGH_SPEED_OPERATION': 4,
    # Superspeed operation supported (5000MBit/s).
    'LIBUSB_5GBPS_OPERATION': 8,
})

# Error codes. Most libusb functions return 0 on success or one of these
# codes on failure.
libusb_error = Enum({
    # Success (no error)
    'LIBUSB_SUCCESS': 0,
    # Input/output error
    'LIBUSB_ERROR_IO': -1,
    # Invalid parameter
    'LIBUSB_ERROR_INVALID_PARAM': -2,
    # Access denied (insufficient permissions)
    'LIBUSB_ERROR_ACCESS': -3,
    # No such device (it may have been disconnected)
    'LIBUSB_ERROR_NO_DEVICE': -4,
    # Entity not found
    'LIBUSB_ERROR_NOT_FOUND': -5,
    # Resource busy
    'LIBUSB_ERROR_BUSY': -6,
    # Operation timed out
    'LIBUSB_ERROR_TIMEOUT': -7,
    # Overflow
    'LIBUSB_ERROR_OVERFLOW': -8,
    # Pipe error
    'LIBUSB_ERROR_PIPE': -9,
    # System call interrupted (perhaps due to signal)
    'LIBUSB_ERROR_INTERRUPTED': -10,
    # Insufficient memory
    'LIBUSB_ERROR_NO_MEM': -11,
    # Operation not supported or unimplemented on this platform
    'LIBUSB_ERROR_NOT_SUPPORTED': -12,
    # Other error
    'LIBUSB_ERROR_OTHER': -99,
})

# Transfer status codes
libusb_transfer_status = Enum({
    # Transfer completed without error. Note that this does not indicate
    # that the entire amount of requested data was transferred.
    'LIBUSB_TRANSFER_COMPLETED': 0,
    # Transfer failed
    'LIBUSB_TRANSFER_ERROR': 1,
    # Transfer timed out
    'LIBUSB_TRANSFER_TIMED_OUT': 2,
    # Transfer was cancelled
    'LIBUSB_TRANSFER_CANCELLED': 3,
    # For bulk/interrupt endpoints: halt condition detected (endpoint
    # stalled). For control endpoints: control request not supported.
    'LIBUSB_TRANSFER_STALL': 4,
    # Device was disconnected
    'LIBUSB_TRANSFER_NO_DEVICE': 5,
    # Device sent more data than requested
    'LIBUSB_TRANSFER_OVERFLOW': 6,
})

# libusb_transfer.flags values
libusb_transfer_flags = Enum({
    # Report short frames as errors
    'LIBUSB_TRANSFER_SHORT_NOT_OK': 1 << 0,
    # Automatically free() transfer buffer during libusb_free_transfer()
    'LIBUSB_TRANSFER_FREE_BUFFER': 1 << 1,
    # Automatically call libusb_free_transfer() after callback returns.
    # If this flag is set, it is illegal to call libusb_free_transfer()
    # from your transfer callback, as this will result in a double-free
    # when this flag is acted upon.
    'LIBUSB_TRANSFER_FREE_TRANSFER': 1 << 2,
    # Terminate transfers that are a multiple of the endpoint's
    # wMaxPacketSize with an extra zero length packet.
    'LIBUSB_TRANSFER_ADD_ZERO_PACKET': 1 << 3,
})

# Isochronous packet descriptor.
class libusb_iso_packet_descriptor(Structure):
    _fields_ = [('length', c_uint),
                ('actual_length', c_uint),
                ('status', c_int)] # enum libusb_transfer_status
libusb_iso_packet_descriptor_p = POINTER(libusb_iso_packet_descriptor)

class libusb_transfer(Structure):
    pass
libusb_transfer_p = POINTER(libusb_transfer)

libusb_transfer_cb_fn_p = CFUNCTYPE(None, libusb_transfer_p)

_libusb_transfer_fields = [
    ('dev_handle', libusb_device_handle_p),
    ('flags', c_uint8),
    ('endpoint', c_uchar),
    ('type', c_uchar),
    ('timeout', c_uint),
    ('status', c_int), # enum libusb_transfer_status
    ('length', c_int),
    ('actual_length', c_int),
    ('callback', libusb_transfer_cb_fn_p),
    ('user_data', c_void_p),
    ('buffer', c_void_p),
    ('num_iso_packets', c_int),
    ('iso_packet_desc', libusb_iso_packet_descriptor)
]
if 'FreeBSD' in platform.system() and getattr(
        libusb, 'libusb_get_string_descriptor', None
    ) is None:
    # Old FreeBSD version has a slight ABI incompatibility.
    # Work around it unless libusb_get_string_descriptor is available, as it
    # is only available on fixed versions.
    assert _libusb_transfer_fields[2][0] == 'endpoint'
    _libusb_transfer_fields[2] = ('endpoint', c_uint32)
    assert _libusb_transfer_fields[11][0] == 'num_iso_packets'
    _libusb_transfer_fields.insert(11, ('os_priv', c_void_p))

# pylint: disable=protected-access
libusb_transfer._fields_ = _libusb_transfer_fields
# pylint: enable=protected-access

libusb_capability = Enum({
    # The libusb_has_capability() API is available.
    'LIBUSB_CAP_HAS_CAPABILITY': 0x0000,
    # Hotplug support is available.
    'LIBUSB_CAP_HAS_HOTPLUG': 0x0001,
    # The library can access HID devices without requiring user intervention.
    'LIBUSB_CAP_HAS_HID_ACCESS': 0x0100,
    # The library supports detaching of the default USB driver.
    'LIBUSB_CAP_SUPPORTS_DETACH_KERNEL_DRIVER': 0x0101,
})

libusb_log_level = Enum({
    'LIBUSB_LOG_LEVEL_NONE': 0,
    'LIBUSB_LOG_LEVEL_ERROR': 1,
    'LIBUSB_LOG_LEVEL_WARNING': 2,
    'LIBUSB_LOG_LEVEL_INFO': 3,
    'LIBUSB_LOG_LEVEL_DEBUG': 4,
})

#int libusb_init(libusb_context **ctx);
libusb_init = libusb.libusb_init
libusb_init.argtypes = [libusb_context_p_p]
#void libusb_exit(libusb_context *ctx);
libusb_exit = libusb.libusb_exit
libusb_exit.argtypes = [libusb_context_p]
libusb_exit.restype = None
#void libusb_set_debug(libusb_context *ctx, int level);
libusb_set_debug = libusb.libusb_set_debug
libusb_set_debug.argtypes = [libusb_context_p, c_int]
libusb_set_debug.restype = None
#const struct libusb_version * libusb_get_version(void);
try:
    libusb_get_version = libusb.libusb_get_version
except AttributeError:
    _dummy_version = libusb_version(0, 0, 0, 0, b'', b'')
    _dummy_version_p = pointer(_dummy_version)
    def libusb_get_version():
        return _dummy_version_p
else:
    libusb_get_version.argtypes = []
    libusb_get_version.restype = POINTER(libusb_version)
#int libusb_has_capability(uint32_t capability);
try:
    libusb_has_capability = libusb.libusb_has_capability
except AttributeError:
    def libusb_has_capability(_):
        return 0
else:
    libusb_has_capability.argtypes = [c_uint32]
    libusb_has_capability.restype = c_int
try:
    # Note: Should be equivalent to libusb_error.get (except libusb_error.get
    # one raises on unknown values).
    #char *libusb_error_name(int errcode);
    libusb_error_name = libusb.libusb_error_name
except AttributeError:
    # pylint: disable=unused-argument
    def libusb_error_name(errcode):
        return None
    # pylint: enable=unused-argument
else:
    libusb_error_name.argtypes = [c_int]
    libusb_error_name.restype = c_char_p

# Note on libusb_strerror, libusb_setlocale and future functions in the
# same spirit:
# I do not think end-user-facing messages belong to a technical library.
# Such features bring a new, non essential set of problems, and is a luxury
# I do not want to spend time supporting considering limited resources and
# more important stuff to work on.
# For backward compatibility, expose libusb_strerror placeholder.
# pylint: disable=unused-argument
def libusb_strerror(errcode):
    return None
# pylint: enable=unused-argument

#ssize_t libusb_get_device_list(libusb_context *ctx,
#        libusb_device ***list);
libusb_get_device_list = libusb.libusb_get_device_list
libusb_get_device_list.argtypes = [libusb_context_p, libusb_device_p_p_p]
libusb_get_device_list.restype = c_ssize_t
#void libusb_free_device_list(libusb_device **list, int unref_devices);
libusb_free_device_list = libusb.libusb_free_device_list
libusb_free_device_list.argtypes = [libusb_device_p_p, c_int]
libusb_free_device_list.restype = None
#libusb_device *libusb_ref_device(libusb_device *dev);
libusb_ref_device = libusb.libusb_ref_device
libusb_ref_device.argtypes = [libusb_device_p]
libusb_ref_device.restype = libusb_device_p
#void libusb_unref_device(libusb_device *dev);
libusb_unref_device = libusb.libusb_unref_device
libusb_unref_device.argtypes = [libusb_device_p]
libusb_unref_device.restype = None

#int libusb_get_configuration(libusb_device_handle *dev, int *config);
libusb_get_configuration = libusb.libusb_get_configuration
libusb_get_configuration.argtypes = [libusb_device_handle_p, c_int_p]
#int libusb_get_device_descriptor(libusb_device *dev,
#        struct libusb_device_descriptor *desc);
libusb_get_device_descriptor = libusb.libusb_get_device_descriptor
libusb_get_device_descriptor.argtypes = [
    libusb_device_p, libusb_device_descriptor_p]
#int libusb_get_active_config_descriptor(libusb_device *dev,
#        struct libusb_config_descriptor **config);
libusb_get_active_config_descriptor = libusb.libusb_get_active_config_descriptor
libusb_get_active_config_descriptor.argtypes = [
    libusb_device_p, libusb_config_descriptor_p_p]
#int libusb_get_config_descriptor(libusb_device *dev, uint8_t config_index,
#        struct libusb_config_descriptor **config);
libusb_get_config_descriptor = libusb.libusb_get_config_descriptor
libusb_get_config_descriptor.argtypes = [
    libusb_device_p, c_uint8, libusb_config_descriptor_p_p]
#int libusb_get_config_descriptor_by_value(libusb_device *dev,
#        uint8_t bConfigurationValue, struct libusb_config_descriptor **config);
libusb_get_config_descriptor_by_value = \
    libusb.libusb_get_config_descriptor_by_value
libusb_get_config_descriptor_by_value.argtypes = [
    libusb_device_p, c_uint8, libusb_config_descriptor_p_p]
#void libusb_free_config_descriptor(struct libusb_config_descriptor *config);
libusb_free_config_descriptor = libusb.libusb_free_config_descriptor
libusb_free_config_descriptor.argtypes = [libusb_config_descriptor_p]
libusb_free_config_descriptor.restype = None
#uint8_t libusb_get_bus_number(libusb_device *dev);
libusb_get_bus_number = libusb.libusb_get_bus_number
libusb_get_bus_number.argtypes = [libusb_device_p]
libusb_get_bus_number.restype = c_uint8
try:
    #uint8_t libusb_get_port_number(libusb_device *dev);
    libusb_get_port_number = libusb.libusb_get_port_number
except AttributeError:
    pass
else:
    libusb_get_port_number.argtypes = [libusb_device_p]
    libusb_get_port_number.restype = c_uint8
try:
    #int libusb_get_port_numbers(libusb_device *dev,
    #       uint8_t* port_numbers, int port_numbers_len);
    libusb_get_port_numbers = libusb.libusb_get_port_numbers
except AttributeError:
    pass
else:
    libusb_get_port_numbers.argtypes = [
        libusb_device_p, POINTER(c_uint8), c_int]
    libusb_get_port_numbers.restype = c_int
# Missing: libusb_get_port_path (deprecated since 1.0.16)
try:
    #libusb_device * LIBUSB_CALL libusb_get_parent(libusb_device *dev);
    libusb_get_parent = libusb.libusb_get_parent
except AttributeError:
    pass
else:
    libusb_get_parent.argtypes = [libusb_device_p]
    libusb_get_parent.restype = libusb_device_p
#uint8_t libusb_get_device_address(libusb_device *dev);
libusb_get_device_address = libusb.libusb_get_device_address
libusb_get_device_address.argtypes = [libusb_device_p]
libusb_get_device_address.restype = c_uint8
try:
    #int libusb_get_device_speed(libusb_device *dev);
    libusb_get_device_speed = libusb.libusb_get_device_speed
except AttributeError:
    # Place holder
    def libusb_get_device_speed(_):
        # pylint: disable=undefined-variable
        return LIBUSB_SPEED_UNKNOWN
        # pylint: enable=undefined-variable
else:
    libusb_get_device_speed.argtypes = [libusb_device_p]
#int libusb_get_max_packet_size(libusb_device *dev, unsigned char endpoint);
libusb_get_max_packet_size = libusb.libusb_get_max_packet_size
libusb_get_max_packet_size.argtypes = [libusb_device_p, c_uchar]
#int libusb_get_max_iso_packet_size(libusb_device *dev, unsigned char endpoint);
try:
    libusb_get_max_iso_packet_size = libusb.libusb_get_max_iso_packet_size
except AttributeError:
    # FreeBSD's reimplementation of the API [used to ]lack[s] this function.
    # It has been added in r234193, but is lacking in default 9.x install as
    # of this change. Provide a fallback to error-out only if actually used.
    # pylint: disable=unused-argument
    def libusb_get_max_iso_packet_size(_, __):
        raise NotImplementedError
    # pylint: enable=unused-argument
else:
    libusb_get_max_iso_packet_size.argtypes = [libusb_device_p, c_uchar]

#int libusb_open(libusb_device *dev, libusb_device_handle **handle);
libusb_open = libusb.libusb_open
libusb_open.argtypes = [libusb_device_p, libusb_device_handle_p_p]
#void libusb_close(libusb_device_handle *dev_handle);
libusb_close = libusb.libusb_close
libusb_close.argtypes = [libusb_device_handle_p]
libusb_close.restype = None
#libusb_device *libusb_get_device(libusb_device_handle *dev_handle);
libusb_get_device = libusb.libusb_get_device
libusb_get_device.argtypes = [libusb_device_handle_p]
libusb_get_device.restype = libusb_device_p

#int libusb_set_configuration(libusb_device_handle *dev, int configuration);
libusb_set_configuration = libusb.libusb_set_configuration
libusb_set_configuration.argtypes = [libusb_device_handle_p, c_int]
#int libusb_claim_interface(libusb_device_handle *dev, int iface);
libusb_claim_interface = libusb.libusb_claim_interface
libusb_claim_interface.argtypes = [libusb_device_handle_p, c_int]
#int libusb_release_interface(libusb_device_handle *dev, int iface);
libusb_release_interface = libusb.libusb_release_interface
libusb_release_interface.argtypes = [libusb_device_handle_p, c_int]

#libusb_device_handle *libusb_open_device_with_vid_pid(libusb_context *ctx,
#        uint16_t vendor_id, uint16_t product_id);
libusb_open_device_with_vid_pid = libusb.libusb_open_device_with_vid_pid
libusb_open_device_with_vid_pid.argtypes = [
    libusb_context_p, c_uint16, c_uint16]
libusb_open_device_with_vid_pid.restype = libusb_device_handle_p

#int libusb_set_interface_alt_setting(libusb_device_handle *dev,
#        int interface_number, int alternate_setting);
libusb_set_interface_alt_setting = libusb.libusb_set_interface_alt_setting
libusb_set_interface_alt_setting.argtypes = [
    libusb_device_handle_p, c_int, c_int]
#int libusb_clear_halt(libusb_device_handle *dev, unsigned char endpoint);
libusb_clear_halt = libusb.libusb_clear_halt
libusb_clear_halt.argtypes = [libusb_device_handle_p, c_uchar]
#int libusb_reset_device(libusb_device_handle *dev);
libusb_reset_device = libusb.libusb_reset_device
libusb_reset_device.argtypes = [libusb_device_handle_p]

#int libusb_kernel_driver_active(libusb_device_handle *dev, int interface);
libusb_kernel_driver_active = libusb.libusb_kernel_driver_active
libusb_kernel_driver_active.argtypes = [libusb_device_handle_p, c_int]
#int libusb_detach_kernel_driver(libusb_device_handle *dev, int interface);
libusb_detach_kernel_driver = libusb.libusb_detach_kernel_driver
libusb_detach_kernel_driver.argtypes = [libusb_device_handle_p, c_int]
#int libusb_attach_kernel_driver(libusb_device_handle *dev, int interface);
libusb_attach_kernel_driver = libusb.libusb_attach_kernel_driver
libusb_attach_kernel_driver.argtypes = [libusb_device_handle_p, c_int]
try:
    #int libusb_set_auto_detach_kernel_driver(
    #       libusb_device_handle *dev, int enable);
    libusb_set_auto_detach_kernel_driver = \
        libusb.libusb_set_auto_detach_kernel_driver
except AttributeError:
    pass
else:
    libusb_set_auto_detach_kernel_driver.argtypes = [
        libusb_device_handle_p, c_int]
    libusb_set_auto_detach_kernel_driver.restype = c_int

# Get the data section of a control transfer. This convenience function is here
# to remind you that the data does not start until 8 bytes into the actual
# buffer, as the setup packet comes first.
#
# 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

def libusb_control_transfer_get_data(transfer_p):
    transfer = transfer_p.contents
    return buffer_at(transfer.buffer, transfer.length)[
        LIBUSB_CONTROL_SETUP_SIZE:]

def libusb_control_transfer_get_setup(transfer_p):
    return cast(transfer_p.contents.buffer, libusb_control_setup_p)

def libusb_fill_control_setup(
        setup_p, bmRequestType, bRequest, wValue, wIndex, wLength):
    setup = cast(setup_p, libusb_control_setup_p).contents
    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);
libusb_alloc_transfer = libusb.libusb_alloc_transfer
libusb_alloc_transfer.argtypes = [c_int]
libusb_alloc_transfer.restype = libusb_transfer_p
#int libusb_submit_transfer(struct libusb_transfer *transfer);
libusb_submit_transfer = libusb.libusb_submit_transfer
libusb_submit_transfer.argtypes = [libusb_transfer_p]
#int libusb_cancel_transfer(struct libusb_transfer *transfer);
libusb_cancel_transfer = libusb.libusb_cancel_transfer
libusb_cancel_transfer.argtypes = [libusb_transfer_p]
#void libusb_free_transfer(struct libusb_transfer *transfer);
libusb_free_transfer = libusb.libusb_free_transfer
libusb_free_transfer.argtypes = [libusb_transfer_p]
libusb_free_transfer.restype = None

# pylint: disable=redefined-builtin
def libusb_fill_control_transfer(
        transfer_p, dev_handle, buffer, callback, user_data, timeout):
    transfer = transfer_p.contents
    transfer.dev_handle = dev_handle
    transfer.endpoint = 0
    # pylint: disable=undefined-variable
    transfer.type = LIBUSB_TRANSFER_TYPE_CONTROL
    # pylint: enable=undefined-variable
    transfer.timeout = timeout
    transfer.buffer = cast(buffer, c_void_p)
    if buffer is not None:
        setup = cast(buffer, libusb_control_setup_p).contents
        # pylint: disable=undefined-variable
        transfer.length = LIBUSB_CONTROL_SETUP_SIZE + \
            libusb_le16_to_cpu(setup.wLength)
        # pylint: enable=undefined-variable
    transfer.user_data = user_data
    transfer.callback = callback
# pylint: enable=redefined-builtin

# pylint: disable=redefined-builtin
def libusb_fill_bulk_transfer(
        transfer_p, dev_handle, endpoint, buffer, length,
        callback, user_data, timeout):
    transfer = transfer_p.contents
    transfer.dev_handle = dev_handle
    transfer.endpoint = endpoint
    # pylint: disable=undefined-variable
    transfer.type = LIBUSB_TRANSFER_TYPE_BULK
    # pylint: enable=undefined-variable
    transfer.timeout = timeout
    transfer.buffer = cast(buffer, c_void_p)
    transfer.length = length
    transfer.user_data = user_data
    transfer.callback = callback
# pylint: enable=redefined-builtin

# pylint: disable=redefined-builtin
def libusb_fill_interrupt_transfer(
        transfer_p, dev_handle, endpoint, buffer,
        length, callback, user_data, timeout):
    transfer = transfer_p.contents
    transfer.dev_handle = dev_handle
    transfer.endpoint = endpoint
    # pylint: disable=undefined-variable
    transfer.type = LIBUSB_TRANSFER_TYPE_INTERRUPT
    # pylint: enable=undefined-variable
    transfer.timeout = timeout
    transfer.buffer = cast(buffer, c_void_p)
    transfer.length = length
    transfer.user_data = user_data
    transfer.callback = callback
# pylint: enable=redefined-builtin

# pylint: disable=redefined-builtin
def libusb_fill_iso_transfer(
        transfer_p, dev_handle, endpoint, buffer, length,
        num_iso_packets, callback, user_data, timeout):
    transfer = transfer_p.contents
    transfer.dev_handle = dev_handle
    transfer.endpoint = endpoint
    # pylint: disable=undefined-variable
    transfer.type = LIBUSB_TRANSFER_TYPE_ISOCHRONOUS
    # pylint: enable=undefined-variable
    transfer.timeout = timeout
    transfer.buffer = cast(buffer, c_void_p)
    transfer.length = length
    transfer.num_iso_packets = num_iso_packets
    transfer.user_data = user_data
    transfer.callback = callback
# pylint: enable=redefined-builtin

def _get_iso_packet_list(transfer):
    list_type = libusb_iso_packet_descriptor * transfer.num_iso_packets
    return list_type.from_address(addressof(transfer.iso_packet_desc))

def get_iso_packet_list(transfer_p):
    """
    Python-specific helper extracting a list of iso packet descriptors,
    because it's not as straight-forward as in C.
    """
    return _get_iso_packet_list(transfer_p.contents)

def _get_iso_packet_buffer(transfer, offset, length):
    return buffer_at(transfer.buffer + offset, length)

def get_iso_packet_buffer_list(transfer_p):
    """
    Python-specific helper extracting a list of iso packet buffers.
    """
    transfer = transfer_p.contents
    offset = 0
    result = []
    append = result.append
    for iso_transfer in _get_iso_packet_list(transfer):
        length = iso_transfer.length
        append(_get_iso_packet_buffer(transfer, offset, length))
        offset += length
    return result

def get_extra(descriptor):
    """
    Python-specific helper to access "extra" field of descriptors,
    because it's not as straight-forward as in C.
    Returns a list, where each entry is an individual extra descriptor.
    """
    result = []
    extra_length = descriptor.extra_length
    if extra_length:
        extra = buffer_at(descriptor.extra, extra_length)
        append = result.append
        while extra:
            length = extra[0]
            if not 0 < length <= len(extra):
                raise ValueError(
                    'Extra descriptor %i is incomplete/invalid' % (
                        len(result),
                    ),
                )
            append(extra[:length])
            extra = extra[length:]
    return result

def libusb_set_iso_packet_lengths(transfer_p, length):
    transfer = transfer_p.contents
    for iso_packet_desc in _get_iso_packet_list(transfer):
        iso_packet_desc.length = length

def libusb_get_iso_packet_buffer(transfer_p, packet):
    transfer = transfer_p.contents
    offset = 0
    if packet >= transfer.num_iso_packets:
        return None
    iso_packet_desc_list = _get_iso_packet_list(transfer)
    for i in xrange(packet):
        offset += iso_packet_desc_list[i].length
    return _get_iso_packet_buffer(
        transfer, offset, iso_packet_desc_list[packet].length)

def libusb_get_iso_packet_buffer_simple(transfer_p, packet):
    transfer = transfer_p.contents
    if packet >= transfer.num_iso_packets:
        return None
    iso_length = transfer.iso_packet_desc.length
    return _get_iso_packet_buffer(transfer, iso_length * packet, iso_length)

# 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);
libusb_control_transfer = libusb.libusb_control_transfer
libusb_control_transfer.argtypes = [libusb_device_handle_p, c_uint8, c_uint8,
                                    c_uint16, c_uint16, c_void_p, c_uint16,
                                    c_uint]

#int libusb_bulk_transfer(libusb_device_handle *dev_handle,
#        unsigned char endpoint, unsigned char *data, int length,
#        int *actual_length, unsigned int timeout);
libusb_bulk_transfer = libusb.libusb_bulk_transfer
libusb_bulk_transfer.argtypes = [libusb_device_handle_p, c_uchar, c_void_p,
                                 c_int, c_int_p, c_uint]

#int libusb_interrupt_transfer(libusb_device_handle *dev_handle,
#        unsigned char endpoint, unsigned char *data, int length,
#        int *actual_length, unsigned int timeout);
libusb_interrupt_transfer = libusb.libusb_interrupt_transfer
libusb_interrupt_transfer.argtypes = [libusb_device_handle_p, c_uchar,
                                      c_void_p, c_int, c_int_p, c_uint]

# pylint: disable=undefined-variable
def libusb_get_descriptor(dev, desc_type, desc_index, data, length):
    return libusb_control_transfer(dev, LIBUSB_ENDPOINT_IN,
                                   LIBUSB_REQUEST_GET_DESCRIPTOR,
                                   (desc_type << 8) | desc_index, 0, data,
                                   length, 1000)
# pylint: enable=undefined-variable

# pylint: disable=undefined-variable
def libusb_get_string_descriptor(dev, desc_index, langid, data, length):
    return libusb_control_transfer(dev, LIBUSB_ENDPOINT_IN,
                                   LIBUSB_REQUEST_GET_DESCRIPTOR,
                                   (LIBUSB_DT_STRING << 8) | desc_index,
                                   langid, data, length, 1000)
# pylint: enable=undefined-variable

#int libusb_get_string_descriptor_ascii(libusb_device_handle *dev,
#        uint8_t index, unsigned char *data, int length);
libusb_get_string_descriptor_ascii = libusb.libusb_get_string_descriptor_ascii
libusb_get_string_descriptor_ascii.argtypes = [libusb_device_handle_p,
                                               c_uint8, c_void_p, c_int]

# polling and timeouts

#int libusb_try_lock_events(libusb_context *ctx);
libusb_try_lock_events = libusb.libusb_try_lock_events
libusb_try_lock_events.argtypes = [libusb_context_p]
#void libusb_lock_events(libusb_context *ctx);
libusb_lock_events = libusb.libusb_lock_events
libusb_lock_events.argtypes = [libusb_context_p]
#void libusb_unlock_events(libusb_context *ctx);
libusb_unlock_events = libusb.libusb_unlock_events
libusb_unlock_events.argtypes = [libusb_context_p]
libusb_unlock_events.restype = None
#int libusb_event_handling_ok(libusb_context *ctx);
libusb_event_handling_ok = libusb.libusb_event_handling_ok
libusb_event_handling_ok.argtypes = [libusb_context_p]
#int libusb_event_handler_active(libusb_context *ctx);
libusb_event_handler_active = libusb.libusb_event_handler_active
libusb_event_handler_active.argtypes = [libusb_context_p]
#void libusb_lock_event_waiters(libusb_context *ctx);
libusb_lock_event_waiters = libusb.libusb_lock_event_waiters
libusb_lock_event_waiters.argtypes = [libusb_context_p]
libusb_lock_event_waiters.restype = None
#void libusb_unlock_event_waiters(libusb_context *ctx);
libusb_unlock_event_waiters = libusb.libusb_unlock_event_waiters
libusb_unlock_event_waiters.argtypes = []
libusb_unlock_event_waiters.restype = None
#int libusb_wait_for_event(libusb_context *ctx, struct timeval *tv);
libusb_wait_for_event = libusb.libusb_wait_for_event
libusb_wait_for_event.argtypes = [libusb_context_p, timeval_p]

#int libusb_handle_events_timeout(libusb_context *ctx, struct timeval *tv);
libusb_handle_events_timeout = libusb.libusb_handle_events_timeout
libusb_handle_events_timeout.argtypes = [libusb_context_p, timeval_p]
#int libusb_handle_events_timeout_completed(libusb_context *ctx,
#   struct timeval *tv, int *completed);
try:
    libusb_handle_events_timeout_completed = libusb.\
        libusb_handle_events_timeout_completed
except AttributeError:
    # No safe replacement possible.
    pass
else:
    libusb_handle_events_timeout_completed.argtypes = [
        libusb_context_p, timeval_p, c_int_p]
#int libusb_handle_events(libusb_context *ctx);
libusb_handle_events = libusb.libusb_handle_events
libusb_handle_events.argtypes = [libusb_context_p]
#int libusb_handle_events_completed(libusb_context *ctx, int *completed);
try:
    libusb_handle_events_completed = libusb.libusb_handle_events_completed
except AttributeError:
    # No safe replacement possible.
    pass
else:
    libusb_handle_events_completed.argtypes = [libusb_context_p, c_int_p]
#int libusb_handle_events_locked(libusb_context *ctx, struct timeval *tv);
libusb_handle_events_locked = libusb.libusb_handle_events_locked
libusb_handle_events_locked.argtypes = [libusb_context_p, timeval_p]
#int libusb_get_next_timeout(libusb_context *ctx, struct timeval *tv);
libusb_get_next_timeout = libusb.libusb_get_next_timeout
libusb_get_next_timeout.argtypes = [libusb_context_p, timeval_p]

class libusb_pollfd(Structure):
    _fields_ = [
        ('fd', c_int),
        ('events', c_short),
    ]
libusb_pollfd_p = POINTER(libusb_pollfd)
libusb_pollfd_p_p = POINTER(libusb_pollfd_p)

libusb_pollfd_added_cb_p = CFUNCTYPE(None, c_int, c_short, py_object)
libusb_pollfd_removed_cb_p = CFUNCTYPE(None, c_int, py_object)

#const struct libusb_pollfd **libusb_get_pollfds(libusb_context *ctx);
libusb_get_pollfds = libusb.libusb_get_pollfds
libusb_get_pollfds.argtypes = [libusb_context_p]
libusb_get_pollfds.restype = libusb_pollfd_p_p
#void libusb_set_pollfd_notifiers(libusb_context *ctx,
#        libusb_pollfd_added_cb added_cb, libusb_pollfd_removed_cb removed_cb,
#        void *user_data);
libusb_set_pollfd_notifiers = libusb.libusb_set_pollfd_notifiers
libusb_set_pollfd_notifiers.argtypes = [libusb_context_p,
                                        libusb_pollfd_added_cb_p,
                                        libusb_pollfd_removed_cb_p, py_object]
libusb_set_pollfd_notifiers.restype = None
try:
    #void libusb_get_pollfds(const struct libusb_pollfd **);
    libusb_free_pollfds = libusb.libusb_free_pollfds
    libusb_free_pollfds.argtypes = [libusb_pollfd_p_p]
    libusb_free_pollfds.restype = None
except AttributeError:
    # Not a safe replacement in general, but the versions of libusb that lack
    # libusb_free_pollfds() only provide that function on *nix, where
    # Python's free() and libusb's free() are ~always the same anyways.
    libusb_free_pollfds = CDLL(None).free

#typedef int libusb_hotplug_callback_handle;
libusb_hotplug_callback_handle = c_int

libusb_hotplug_flag = Enum({
    'LIBUSB_HOTPLUG_ENUMERATE': 1,
})

libusb_hotplug_event = Enum({
    'LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED': 0x01,
    'LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT': 0x02,
})

LIBUSB_HOTPLUG_MATCH_ANY = -1

#typedef int (*libusb_hotplug_callback_fn)(libusb_context *ctx,
#        libusb_device *device, libusb_hotplug_event event, void *user_data);
libusb_hotplug_callback_fn_p = CFUNCTYPE(
    c_int, libusb_context_p, libusb_device_p, c_int, c_void_p)

#int libusb_hotplug_register_callback(libusb_context *ctx,
#        libusb_hotplug_event events, libusb_hotplug_flag flags,
#        int vendor_id, int product_id, int dev_class,
#        libusb_hotplug_callback_fn cb_fn, void *user_data,
#        libusb_hotplug_callback_handle *handle);
try:
    libusb_hotplug_register_callback = libusb.libusb_hotplug_register_callback
except AttributeError:
    pass
else:
    libusb_hotplug_register_callback.argtypes = [
        libusb_context_p,
        c_int, c_int,
        c_int, c_int, c_int,
        libusb_hotplug_callback_fn_p, c_void_p,
        POINTER(libusb_hotplug_callback_handle),
    ]
    libusb_hotplug_register_callback.restype = c_int

#void libusb_hotplug_deregister_callback(libusb_context *ctx,
#        libusb_hotplug_callback_handle handle);
try:
    libusb_hotplug_deregister_callback = \
        libusb.libusb_hotplug_deregister_callback
except AttributeError:
    pass
else:
    libusb_hotplug_deregister_callback.argtypes = [
        libusb_context_p,
        libusb_hotplug_callback_handle,
    ]
    libusb_hotplug_deregister_callback.restype = None

# /libusb.h
