text: /*
   * windows backend for libusb 1.0
   * Copyright © 2009-2012 Pete Batard <pete@akeo.ie>
   * With contributions from Michael Plante, Orin Eman et al.
   * Parts of this code adapted from libusb-win32-v1 by Stephan Meyer
   * HID Reports IOCTLs inspired from HIDAPI by Alan Ott, Signal 11 Software
   * Hash table functions adapted from glibc, by Ulrich Drepper et al.
   * Major code testing contribution by Xiaofan Chen
   *
   * 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
   */
  
  #include <config.h>
  
  #if !defined(USE_USBDK)
  
  #include <windows.h>
  #include <setupapi.h>
  #include <ctype.h>
  #include <errno.h>
  #include <fcntl.h>
  #include <process.h>
  #include <stdio.h>
  #include <inttypes.h>
  #include <objbase.h>
  #include <winioctl.h>
  
  #include "libusbi.h"
  #include "poll_windows.h"
  #include "windows_winusb.h"
  
  #define HANDLE_VALID(h) (((h) != 0) && ((h) != INVALID_HANDLE_VALUE))
  
  // The 2 macros below are used in conjunction with safe loops.
  #define LOOP_CHECK(fcall)			\
  	{					\
  		r = fcall;			\
  		if (r != LIBUSB_SUCCESS)	\
  			continue;		\
  	}
  #define LOOP_BREAK(err)				\
  	{					\
  		r = err;			\
  		continue;			\
  	}
  
  // WinUSB-like API prototypes
  static int winusbx_init(int sub_api, struct libusb_context *ctx);
  static int winusbx_exit(int sub_api);
  static int winusbx_open(int sub_api, struct libusb_device_handle *dev_handle);
  static void winusbx_close(int sub_api, struct libusb_device_handle *dev_handle);
  static int winusbx_configure_endpoints(int sub_api, struct libusb_device_handle *dev_handle, int iface);
  static int winusbx_claim_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface);
  static int winusbx_release_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface);
  static int winusbx_submit_control_transfer(int sub_api, struct usbi_transfer *itransfer);
  static int winusbx_set_interface_altsetting(int sub_api, struct libusb_device_handle *dev_handle, int iface, int altsetting);
  static int winusbx_submit_bulk_transfer(int sub_api, struct usbi_transfer *itransfer);
  static int winusbx_clear_halt(int sub_api, struct libusb_device_handle *dev_handle, unsigned char endpoint);
  static int winusbx_abort_transfers(int sub_api, struct usbi_transfer *itransfer);
  static int winusbx_abort_control(int sub_api, struct usbi_transfer *itransfer);
  static int winusbx_reset_device(int sub_api, struct libusb_device_handle *dev_handle);
  static int winusbx_copy_transfer_data(int sub_api, struct usbi_transfer *itransfer, uint32_t io_size);
  // HID API prototypes
  static int hid_init(int sub_api, struct libusb_context *ctx);
  static int hid_exit(int sub_api);
  static int hid_open(int sub_api, struct libusb_device_handle *dev_handle);
  static void hid_close(int sub_api, struct libusb_device_handle *dev_handle);
  static int hid_claim_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface);
  static int hid_release_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface);
  static int hid_set_interface_altsetting(int sub_api, struct libusb_device_handle *dev_handle, int iface, int altsetting);
  static int hid_submit_control_transfer(int sub_api, struct usbi_transfer *itransfer);
  static int hid_submit_bulk_transfer(int sub_api, struct usbi_transfer *itransfer);
  static int hid_clear_halt(int sub_api, struct libusb_device_handle *dev_handle, unsigned char endpoint);
  static int hid_abort_transfers(int sub_api, struct usbi_transfer *itransfer);
  static int hid_reset_device(int sub_api, struct libusb_device_handle *dev_handle);
  static int hid_copy_transfer_data(int sub_api, struct usbi_transfer *itransfer, uint32_t io_size);
  // Composite API prototypes
  static int composite_init(int sub_api, struct libusb_context *ctx);
  static int composite_exit(int sub_api);
  static int composite_open(int sub_api, struct libusb_device_handle *dev_handle);
  static void composite_close(int sub_api, struct libusb_device_handle *dev_handle);
  static int composite_claim_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface);
  static int composite_set_interface_altsetting(int sub_api, struct libusb_device_handle *dev_handle, int iface, int altsetting);
  static int composite_release_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface);
  static int composite_submit_control_transfer(int sub_api, struct usbi_transfer *itransfer);
  static int composite_submit_bulk_transfer(int sub_api, struct usbi_transfer *itransfer);
  static int composite_submit_iso_transfer(int sub_api, struct usbi_transfer *itransfer);
  static int composite_clear_halt(int sub_api, struct libusb_device_handle *dev_handle, unsigned char endpoint);
  static int composite_abort_transfers(int sub_api, struct usbi_transfer *itransfer);
  static int composite_abort_control(int sub_api, struct usbi_transfer *itransfer);
  static int composite_reset_device(int sub_api, struct libusb_device_handle *dev_handle);
  static int composite_copy_transfer_data(int sub_api, struct usbi_transfer *itransfer, uint32_t io_size);
  
  
  // Global variables
  int windows_version = WINDOWS_UNDEFINED;
  static char windows_version_str[128] = "Windows Undefined";
  // Concurrency
  static int concurrent_usage = -1;
  static usbi_mutex_t autoclaim_lock;
  // API globals
  #define CHECK_WINUSBX_AVAILABLE(sub_api)		\
  	do {						\
  		if (sub_api == SUB_API_NOTSET)		\
  			sub_api = priv->sub_api;	\
  		if (!WinUSBX[sub_api].initialized) 	\
  			return LIBUSB_ERROR_ACCESS;	\
  	} while(0)
  
  static HMODULE WinUSBX_handle = NULL;
  static struct winusb_interface WinUSBX[SUB_API_MAX];
  static const char *sub_api_name[SUB_API_MAX] = WINUSBX_DRV_NAMES;
  
  static bool api_hid_available = false;
  #define CHECK_HID_AVAILABLE				\
  	do {						\
  		if (!api_hid_available)			\
  			return LIBUSB_ERROR_ACCESS;	\
  	} while (0)
  
  static inline BOOLEAN guid_eq(const GUID *guid1, const GUID *guid2)
  {
  	if ((guid1 != NULL) && (guid2 != NULL))
  		return (memcmp(guid1, guid2, sizeof(GUID)) == 0);
  
  	return false;
  }
  
  #if defined(ENABLE_LOGGING)
  static char *guid_to_string(const GUID *guid)
  {
  	static char guid_string[MAX_GUID_STRING_LENGTH];
  
  	if (guid == NULL)
  		return NULL;
  
  	sprintf(guid_string, "{%08X-%04X-%04X-%02X%02X-%02X%02X%02X%02X%02X%02X}",
  		(unsigned int)guid->Data1, guid->Data2, guid->Data3,
  		guid->Data4[0], guid->Data4[1], guid->Data4[2], guid->Data4[3],
  		guid->Data4[4], guid->Data4[5], guid->Data4[6], guid->Data4[7]);
  
  	return guid_string;
  }
  #endif
  
  /*
   * Sanitize Microsoft's paths: convert to uppercase, add prefix and fix backslashes.
   * Return an allocated sanitized string or NULL on error.
   */
  static char *sanitize_path(const char *path)
  {
  	const char root_prefix[] = "\\\\.\\";
  	size_t j, size, root_size;
  	char *ret_path = NULL;
  	size_t add_root = 0;
  
  	if (path == NULL)
  		return NULL;
  
  	size = safe_strlen(path) + 1;
  	root_size = sizeof(root_prefix) - 1;
  
  	// Microsoft indiscriminately uses '\\?\', '\\.\', '##?#" or "##.#" for root prefixes.
  	if (!((size > 3) && (((path[0] == '\\') && (path[1] == '\\') && (path[3] == '\\'))
  			|| ((path[0] == '#') && (path[1] == '#') && (path[3] == '#'))))) {
  		add_root = root_size;
  		size += add_root;
  	}
  
  	ret_path = calloc(1, size);
  	if (ret_path == NULL)
  		return NULL;
  
  	safe_strcpy(&ret_path[add_root], size-add_root, path);
  
  	// Ensure consistency with root prefix
  	for (j = 0; j < root_size; j++)
  		ret_path[j] = root_prefix[j];
  
  	// Same goes for '\' and '#' after the root prefix. Ensure '#' is used
  	for (j = root_size; j < size; j++) {
  		ret_path[j] = (char)toupper((int)ret_path[j]); // Fix case too
  		if (ret_path[j] == '\\')
  			ret_path[j] = '#';
  	}
  
  	return ret_path;
  }
  
  /*
   * Cfgmgr32, OLE32 and SetupAPI DLL functions
   */
  static int init_dlls(void)
  {
  	DLL_GET_HANDLE(Cfgmgr32);
  	DLL_LOAD_FUNC(Cfgmgr32, CM_Get_Parent, TRUE);
  	DLL_LOAD_FUNC(Cfgmgr32, CM_Get_Child, TRUE);
  	DLL_LOAD_FUNC(Cfgmgr32, CM_Get_Sibling, TRUE);
  	DLL_LOAD_FUNC(Cfgmgr32, CM_Get_Device_IDA, TRUE);
  
  	// Prefixed to avoid conflict with header files
  	DLL_GET_HANDLE(AdvAPI32);
  	DLL_LOAD_FUNC_PREFIXED(AdvAPI32, p, RegQueryValueExW, TRUE);
  	DLL_LOAD_FUNC_PREFIXED(AdvAPI32, p, RegCloseKey, TRUE);
  
  	DLL_GET_HANDLE(Kernel32);
  	DLL_LOAD_FUNC_PREFIXED(Kernel32, p, IsWow64Process, FALSE);
  
  	DLL_GET_HANDLE(OLE32);
  	DLL_LOAD_FUNC_PREFIXED(OLE32, p, CLSIDFromString, TRUE);
  
  	DLL_GET_HANDLE(SetupAPI);
  	DLL_LOAD_FUNC_PREFIXED(SetupAPI, p, SetupDiGetClassDevsA, TRUE);
  	DLL_LOAD_FUNC_PREFIXED(SetupAPI, p, SetupDiEnumDeviceInfo, TRUE);
  	DLL_LOAD_FUNC_PREFIXED(SetupAPI, p, SetupDiEnumDeviceInterfaces, TRUE);
  	DLL_LOAD_FUNC_PREFIXED(SetupAPI, p, SetupDiGetDeviceInterfaceDetailA, TRUE);
  	DLL_LOAD_FUNC_PREFIXED(SetupAPI, p, SetupDiDestroyDeviceInfoList, TRUE);
  	DLL_LOAD_FUNC_PREFIXED(SetupAPI, p, SetupDiOpenDevRegKey, TRUE);
  	DLL_LOAD_FUNC_PREFIXED(SetupAPI, p, SetupDiGetDeviceRegistryPropertyA, TRUE);
  	DLL_LOAD_FUNC_PREFIXED(SetupAPI, p, SetupDiOpenDeviceInterfaceRegKey, TRUE);
  
  	return LIBUSB_SUCCESS;
  }
  
  static void exit_dlls(void)
  {
  	DLL_FREE_HANDLE(Cfgmgr32);
  	DLL_FREE_HANDLE(AdvAPI32);
  	DLL_FREE_HANDLE(Kernel32);
  	DLL_FREE_HANDLE(OLE32);
  	DLL_FREE_HANDLE(SetupAPI);
  }
  
  /*
   * enumerate interfaces for the whole USB class
   *
   * Parameters:
   * dev_info: a pointer to a dev_info list
   * dev_info_data: a pointer to an SP_DEVINFO_DATA to be filled (or NULL if not needed)
   * usb_class: the generic USB class for which to retrieve interface details
   * index: zero based index of the interface in the device info list
   *
   * Note: it is the responsibility of the caller to free the DEVICE_INTERFACE_DETAIL_DATA
   * structure returned and call this function repeatedly using the same guid (with an
   * incremented index starting at zero) until all interfaces have been returned.
   */
  static bool get_devinfo_data(struct libusb_context *ctx,
  	HDEVINFO *dev_info, SP_DEVINFO_DATA *dev_info_data, const char *usb_class, unsigned _index)
  {
  	if (_index <= 0) {
  		*dev_info = pSetupDiGetClassDevsA(NULL, usb_class, NULL, DIGCF_PRESENT|DIGCF_ALLCLASSES);
  		if (*dev_info == INVALID_HANDLE_VALUE)
  			return false;
  	}
  
  	dev_info_data->cbSize = sizeof(SP_DEVINFO_DATA);
  	if (!pSetupDiEnumDeviceInfo(*dev_info, _index, dev_info_data)) {
  		if (GetLastError() != ERROR_NO_MORE_ITEMS)
  			usbi_err(ctx, "Could not obtain device info data for index %u: %s",
  				_index, windows_error_str(0));
  
  		pSetupDiDestroyDeviceInfoList(*dev_info);
  		*dev_info = INVALID_HANDLE_VALUE;
  		return false;
  	}
  	return true;
  }
  
  /*
   * enumerate interfaces for a specific GUID
   *
   * Parameters:
   * dev_info: a pointer to a dev_info list
   * dev_info_data: a pointer to an SP_DEVINFO_DATA to be filled (or NULL if not needed)
   * guid: the GUID for which to retrieve interface details
   * index: zero based index of the interface in the device info list
   *
   * Note: it is the responsibility of the caller to free the DEVICE_INTERFACE_DETAIL_DATA
   * structure returned and call this function repeatedly using the same guid (with an
   * incremented index starting at zero) until all interfaces have been returned.
   */
  static SP_DEVICE_INTERFACE_DETAIL_DATA_A *get_interface_details(struct libusb_context *ctx,
  	HDEVINFO *dev_info, SP_DEVINFO_DATA *dev_info_data, const GUID *guid, unsigned _index)
  {
  	SP_DEVICE_INTERFACE_DATA dev_interface_data;
  	SP_DEVICE_INTERFACE_DETAIL_DATA_A *dev_interface_details = NULL;
  	DWORD size;
  
  	if (_index <= 0)
  		*dev_info = pSetupDiGetClassDevsA(guid, NULL, NULL, DIGCF_PRESENT|DIGCF_DEVICEINTERFACE);
  
  	if (dev_info_data != NULL) {
  		dev_info_data->cbSize = sizeof(SP_DEVINFO_DATA);
  		if (!pSetupDiEnumDeviceInfo(*dev_info, _index, dev_info_data)) {
  			if (GetLastError() != ERROR_NO_MORE_ITEMS)
  				usbi_err(ctx, "Could not obtain device info data for index %u: %s",
  					_index, windows_error_str(0));
  
  			pSetupDiDestroyDeviceInfoList(*dev_info);
  			*dev_info = INVALID_HANDLE_VALUE;
  			return NULL;
  		}
  	}
  
  	dev_interface_data.cbSize = sizeof(SP_DEVICE_INTERFACE_DATA);
  	if (!pSetupDiEnumDeviceInterfaces(*dev_info, NULL, guid, _index, &dev_interface_data)) {
  		if (GetLastError() != ERROR_NO_MORE_ITEMS)
  			usbi_err(ctx, "Could not obtain interface data for index %u: %s",
  				_index, windows_error_str(0));
  
  		pSetupDiDestroyDeviceInfoList(*dev_info);
  		*dev_info = INVALID_HANDLE_VALUE;
  		return NULL;
  	}
  
  	// Read interface data (dummy + actual) to access the device path
  	if (!pSetupDiGetDeviceInterfaceDetailA(*dev_info, &dev_interface_data, NULL, 0, &size, NULL)) {
  		// The dummy call should fail with ERROR_INSUFFICIENT_BUFFER
  		if (GetLastError() != ERROR_INSUFFICIENT_BUFFER) {
  			usbi_err(ctx, "could not access interface data (dummy) for index %u: %s",
  				_index, windows_error_str(0));
  			goto err_exit;
  		}
  	} else {
  		usbi_err(ctx, "program assertion failed - http://msdn.microsoft.com/en-us/library/ms792901.aspx is wrong.");
  		goto err_exit;
  	}
  
  	dev_interface_details = calloc(1, size);
  	if (dev_interface_details == NULL) {
  		usbi_err(ctx, "could not allocate interface data for index %u.", _index);
  		goto err_exit;
  	}
  
  	dev_interface_details->cbSize = sizeof(SP_DEVICE_INTERFACE_DETAIL_DATA_A);
  	if (!pSetupDiGetDeviceInterfaceDetailA(*dev_info, &dev_interface_data,
  		dev_interface_details, size, &size, NULL)) {
  		usbi_err(ctx, "could not access interface data (actual) for index %u: %s",
  			_index, windows_error_str(0));
  	}
  
  	return dev_interface_details;
  
  err_exit:
  	pSetupDiDestroyDeviceInfoList(*dev_info);
  	*dev_info = INVALID_HANDLE_VALUE;
  	return NULL;
  }
  
  /* For libusb0 filter */
  static SP_DEVICE_INTERFACE_DETAIL_DATA_A *get_interface_details_filter(struct libusb_context *ctx,
  	HDEVINFO *dev_info, SP_DEVINFO_DATA *dev_info_data, const GUID *guid, unsigned _index, char *filter_path)
  {
  	SP_DEVICE_INTERFACE_DATA dev_interface_data;
  	SP_DEVICE_INTERFACE_DETAIL_DATA_A *dev_interface_details = NULL;
  	DWORD size;
  
  	if (_index <= 0)
  		*dev_info = pSetupDiGetClassDevsA(guid, NULL, NULL, DIGCF_PRESENT|DIGCF_DEVICEINTERFACE);
  
  	if (dev_info_data != NULL) {
  		dev_info_data->cbSize = sizeof(SP_DEVINFO_DATA);
  		if (!pSetupDiEnumDeviceInfo(*dev_info, _index, dev_info_data)) {
  			if (GetLastError() != ERROR_NO_MORE_ITEMS)
  				usbi_err(ctx, "Could not obtain device info data for index %u: %s",
  					_index, windows_error_str(0));
  
  			pSetupDiDestroyDeviceInfoList(*dev_info);
  			*dev_info = INVALID_HANDLE_VALUE;
  			return NULL;
  		}
  	}
  
  	dev_interface_data.cbSize = sizeof(SP_DEVICE_INTERFACE_DATA);
  	if (!pSetupDiEnumDeviceInterfaces(*dev_info, NULL, guid, _index, &dev_interface_data)) {
  		if (GetLastError() != ERROR_NO_MORE_ITEMS)
  			usbi_err(ctx, "Could not obtain interface data for index %u: %s",
  				_index, windows_error_str(0));
  
  		pSetupDiDestroyDeviceInfoList(*dev_info);
  		*dev_info = INVALID_HANDLE_VALUE;
  		return NULL;
  	}
  
  	// Read interface data (dummy + actual) to access the device path
  	if (!pSetupDiGetDeviceInterfaceDetailA(*dev_info, &dev_interface_data, NULL, 0, &size, NULL)) {
  		// The dummy call should fail with ERROR_INSUFFICIENT_BUFFER
  		if (GetLastError() != ERROR_INSUFFICIENT_BUFFER) {
  			usbi_err(ctx, "could not access interface data (dummy) for index %u: %s",
  				_index, windows_error_str(0));
  			goto err_exit;
  		}
  	} else {
  		usbi_err(ctx, "program assertion failed - http://msdn.microsoft.com/en-us/library/ms792901.aspx is wrong.");
  		goto err_exit;
  	}
  
  	dev_interface_details = calloc(1, size);
  	if (dev_interface_details == NULL) {
  		usbi_err(ctx, "could not allocate interface data for index %u.", _index);
  		goto err_exit;
  	}
  
  	dev_interface_details->cbSize = sizeof(SP_DEVICE_INTERFACE_DETAIL_DATA_A);
  	if (!pSetupDiGetDeviceInterfaceDetailA(*dev_info, &dev_interface_data, dev_interface_details, size, &size, NULL))
  		usbi_err(ctx, "could not access interface data (actual) for index %u: %s",
  			_index, windows_error_str(0));
  
  	// [trobinso] lookup the libusb0 symbolic index.
  	if (dev_interface_details) {
  		HKEY hkey_device_interface = pSetupDiOpenDeviceInterfaceRegKey(*dev_info, &dev_interface_data, 0, KEY_READ);
  		if (hkey_device_interface != INVALID_HANDLE_VALUE) {
  			DWORD libusb0_symboliclink_index = 0;
  			DWORD value_length = sizeof(DWORD);
  			DWORD value_type = 0;
  			LONG status;
  
  			status = pRegQueryValueExW(hkey_device_interface, L"LUsb0", NULL, &value_type,
  				(LPBYTE)&libusb0_symboliclink_index, &value_length);
  			if (status == ERROR_SUCCESS) {
  				if (libusb0_symboliclink_index < 256) {
  					// libusb0.sys is connected to this device instance.
  					// If the the device interface guid is {F9F3FF14-AE21-48A0-8A25-8011A7A931D9} then it's a filter.
  					safe_sprintf(filter_path, sizeof("\\\\.\\libusb0-0000"), "\\\\.\\libusb0-%04u", (unsigned int)libusb0_symboliclink_index);
  					usbi_dbg("assigned libusb0 symbolic link %s", filter_path);
  				} else {
  					// libusb0.sys was connected to this device instance at one time; but not anymore.
  				}
  			}
  			pRegCloseKey(hkey_device_interface);
  		}
  	}
  
  	return dev_interface_details;
  
  err_exit:
  	pSetupDiDestroyDeviceInfoList(*dev_info);
  	*dev_info = INVALID_HANDLE_VALUE;
  	return NULL;
  }
  
  /*
   * Returns the session ID of a device's nth level ancestor
   * If there's no device at the nth level, return 0
   */
  static unsigned long get_ancestor_session_id(DWORD devinst, unsigned level)
  {
  	DWORD parent_devinst;
  	unsigned long session_id = 0;
  	char *sanitized_path = NULL;
  	char path[MAX_PATH_LENGTH];
  	unsigned i;
  
  	if (level < 1)
  		return 0;
  
  	for (i = 0; i < level; i++) {
  		if (CM_Get_Parent(&parent_devinst, devinst, 0) != CR_SUCCESS)
  			return 0;
  		devinst = parent_devinst;
  	}
  
  	if (CM_Get_Device_IDA(devinst, path, MAX_PATH_LENGTH, 0) != CR_SUCCESS)
  		return 0;
  
  	// TODO: (post hotplug): try without sanitizing
  	sanitized_path = sanitize_path(path);
  	if (sanitized_path == NULL)
  		return 0;
  
  	session_id = htab_hash(sanitized_path);
  	safe_free(sanitized_path);
  	return session_id;
  }
  
  /*
   * Determine which interface the given endpoint address belongs to
   */
  static int get_interface_by_endpoint(struct libusb_config_descriptor *conf_desc, uint8_t ep)
  {
  	const struct libusb_interface *intf;
  	const struct libusb_interface_descriptor *intf_desc;
  	int i, j, k;
  
  	for (i = 0; i < conf_desc->bNumInterfaces; i++) {
  		intf = &conf_desc->interface[i];
  		for (j = 0; j < intf->num_altsetting; j++) {
  			intf_desc = &intf->altsetting[j];
  			for (k = 0; k < intf_desc->bNumEndpoints; k++) {
  				if (intf_desc->endpoint[k].bEndpointAddress == ep) {
  					usbi_dbg("found endpoint %02X on interface %d", intf_desc->bInterfaceNumber, i);
  					return intf_desc->bInterfaceNumber;
  				}
  			}
  		}
  	}
  
  	usbi_dbg("endpoint %02X not found on any interface", ep);
  	return LIBUSB_ERROR_NOT_FOUND;
  }
  
  /*
   * Populate the endpoints addresses of the device_priv interface helper structs
   */
  static int windows_assign_endpoints(struct libusb_device_handle *dev_handle, int iface, int altsetting)
  {
  	int i, r;
  	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
  	struct libusb_config_descriptor *conf_desc;
  	const struct libusb_interface_descriptor *if_desc;
  	struct libusb_context *ctx = DEVICE_CTX(dev_handle->dev);
  
  	r = libusb_get_active_config_descriptor(dev_handle->dev, &conf_desc);
  	if (r != LIBUSB_SUCCESS) {
  		usbi_warn(ctx, "could not read config descriptor: error %d", r);
  		return r;
  	}
  
  	if_desc = &conf_desc->interface[iface].altsetting[altsetting];
  	safe_free(priv->usb_interface[iface].endpoint);
  
  	if (if_desc->bNumEndpoints == 0) {
  		usbi_dbg("no endpoints found for interface %d", iface);
  		libusb_free_config_descriptor(conf_desc);
  		return LIBUSB_SUCCESS;
  	}
  
  	priv->usb_interface[iface].endpoint = malloc(if_desc->bNumEndpoints);
  	if (priv->usb_interface[iface].endpoint == NULL) {
  		libusb_free_config_descriptor(conf_desc);
  		return LIBUSB_ERROR_NO_MEM;
  	}
  
  	priv->usb_interface[iface].nb_endpoints = if_desc->bNumEndpoints;
  	for (i = 0; i < if_desc->bNumEndpoints; i++) {
  		priv->usb_interface[iface].endpoint[i] = if_desc->endpoint[i].bEndpointAddress;
  		usbi_dbg("(re)assigned endpoint %02X to interface %d", priv->usb_interface[iface].endpoint[i], iface);
  	}
  	libusb_free_config_descriptor(conf_desc);
  
  	// Extra init may be required to configure endpoints
  	return priv->apib->configure_endpoints(SUB_API_NOTSET, dev_handle, iface);
  }
  
  // Lookup for a match in the list of API driver names
  // return -1 if not found, driver match number otherwise
  static int get_sub_api(char *driver, int api)
  {
  	int i;
  	const char sep_str[2] = {LIST_SEPARATOR, 0};
  	char *tok, *tmp_str;
  	size_t len = safe_strlen(driver);
  
  	if (len == 0)
  		return SUB_API_NOTSET;
  
  	tmp_str = _strdup(driver);
  	if (tmp_str == NULL)
  		return SUB_API_NOTSET;
  
  	tok = strtok(tmp_str, sep_str);
  	while (tok != NULL) {
  		for (i = 0; i < usb_api_backend[api].nb_driver_names; i++) {
  			if (safe_stricmp(tok, usb_api_backend[api].driver_name_list[i]) == 0) {
  				free(tmp_str);
  				return i;
  			}
  		}
  		tok = strtok(NULL, sep_str);
  	}
  
  	free(tmp_str);
  	return SUB_API_NOTSET;
  }
  
  /*
   * auto-claiming and auto-release helper functions
   */
  static int auto_claim(struct libusb_transfer *transfer, int *interface_number, int api_type)
  {
  	struct libusb_context *ctx = DEVICE_CTX(transfer->dev_handle->dev);
  	struct windows_device_handle_priv *handle_priv = _device_handle_priv(
  		transfer->dev_handle);
  	struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
  	int current_interface = *interface_number;
  	int r = LIBUSB_SUCCESS;
  
  	switch(api_type) {
  	case USB_API_WINUSBX:
  	case USB_API_HID:
  		break;
  	default:
  		return LIBUSB_ERROR_INVALID_PARAM;
  	}
  
  	usbi_mutex_lock(&autoclaim_lock);
  	if (current_interface < 0) { // No serviceable interface was found
  		for (current_interface = 0; current_interface < USB_MAXINTERFACES; current_interface++) {
  			// Must claim an interface of the same API type
  			if ((priv->usb_interface[current_interface].apib->id == api_type)
  					&& (libusb_claim_interface(transfer->dev_handle, current_interface) == LIBUSB_SUCCESS)) {
  				usbi_dbg("auto-claimed interface %d for control request", current_interface);
  				if (handle_priv->autoclaim_count[current_interface] != 0)
  					usbi_warn(ctx, "program assertion failed - autoclaim_count was nonzero");
  				handle_priv->autoclaim_count[current_interface]++;
  				break;
  			}
  		}
  		if (current_interface == USB_MAXINTERFACES) {
  			usbi_err(ctx, "could not auto-claim any interface");
  			r = LIBUSB_ERROR_NOT_FOUND;
  		}
  	} else {
  		// If we have a valid interface that was autoclaimed, we must increment
  		// its autoclaim count so that we can prevent an early release.
  		if (handle_priv->autoclaim_count[current_interface] != 0)
  			handle_priv->autoclaim_count[current_interface]++;
  	}
  	usbi_mutex_unlock(&autoclaim_lock);
  
  	*interface_number = current_interface;
  	return r;
  }
  
  static void auto_release(struct usbi_transfer *itransfer)
  {
  	struct windows_transfer_priv *transfer_priv = usbi_transfer_get_os_priv(itransfer);
  	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
  	libusb_device_handle *dev_handle = transfer->dev_handle;
  	struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
  	int r;
  
  	usbi_mutex_lock(&autoclaim_lock);
  	if (handle_priv->autoclaim_count[transfer_priv->interface_number] > 0) {
  		handle_priv->autoclaim_count[transfer_priv->interface_number]--;
  		if (handle_priv->autoclaim_count[transfer_priv->interface_number] == 0) {
  			r = libusb_release_interface(dev_handle, transfer_priv->interface_number);
  			if (r == LIBUSB_SUCCESS)
  				usbi_dbg("auto-released interface %d", transfer_priv->interface_number);
  			else
  				usbi_dbg("failed to auto-release interface %d (%s)",
  					transfer_priv->interface_number, libusb_error_name((enum libusb_error)r));
  		}
  	}
  	usbi_mutex_unlock(&autoclaim_lock);
  }
  
  /* Windows version dtection */
  static BOOL is_x64(void)
  {
  	BOOL ret = FALSE;
  
  	// Detect if we're running a 32 or 64 bit system
  	if (sizeof(uintptr_t) < 8) {
  		if (pIsWow64Process != NULL)
  			pIsWow64Process(GetCurrentProcess(), &ret);
  	} else {
  		ret = TRUE;
  	}
  
  	return ret;
  }
  
  static void get_windows_version(void)
  {
  	OSVERSIONINFOEXA vi, vi2;
  	const char *w = 0;
  	const char *w64 = "32 bit";
  	char *vptr;
  	size_t vlen;
  	unsigned major, minor;
  	ULONGLONG major_equal, minor_equal;
  	BOOL ws;
  
  	memset(&vi, 0, sizeof(vi));
  	vi.dwOSVersionInfoSize = sizeof(vi);
  	if (!GetVersionExA((OSVERSIONINFOA *)&vi)) {
  		memset(&vi, 0, sizeof(vi));
  		vi.dwOSVersionInfoSize = sizeof(OSVERSIONINFOA);
  		if (!GetVersionExA((OSVERSIONINFOA *)&vi))
  			return;
  	}
  
  	if (vi.dwPlatformId == VER_PLATFORM_WIN32_NT) {
  		if (vi.dwMajorVersion > 6 || (vi.dwMajorVersion == 6 && vi.dwMinorVersion >= 2)) {
  			// Starting with Windows 8.1 Preview, GetVersionEx() does no longer report the actual OS version
  			// See: http://msdn.microsoft.com/en-us/library/windows/desktop/dn302074.aspx
  
  			major_equal = VerSetConditionMask(0, VER_MAJORVERSION, VER_EQUAL);
  			for (major = vi.dwMajorVersion; major <= 9; major++) {
  				memset(&vi2, 0, sizeof(vi2));
  				vi2.dwOSVersionInfoSize = sizeof(vi2);
  				vi2.dwMajorVersion = major;
  				if (!VerifyVersionInfoA(&vi2, VER_MAJORVERSION, major_equal))
  					continue;
  
  				if (vi.dwMajorVersion < major) {
  					vi.dwMajorVersion = major;
  					vi.dwMinorVersion = 0;
  				}
  
  				minor_equal = VerSetConditionMask(0, VER_MINORVERSION, VER_EQUAL);
  				for (minor = vi.dwMinorVersion; minor <= 9; minor++) {
  					memset(&vi2, 0, sizeof(vi2));
  					vi2.dwOSVersionInfoSize = sizeof(vi2);
  					vi2.dwMinorVersion = minor;
  					if (!VerifyVersionInfoA(&vi2, VER_MINORVERSION, minor_equal))
  						continue;
  
  					vi.dwMinorVersion = minor;
  					break;
  				}
  
  				break;
  			}
  		}
  
  		if (vi.dwMajorVersion <= 0xf && vi.dwMinorVersion <= 0xf) {
  			ws = (vi.wProductType <= VER_NT_WORKSTATION);
  			windows_version = vi.dwMajorVersion << 4 | vi.dwMinorVersion;
  			switch (windows_version) {
  			case 0x50: w = "2000"; break;
  			case 0x51: w = "XP"; break;
  			case 0x52: w = ("2003"); break;
  			case 0x60: w = (ws ? "Vista" : "2008"); break;
  			case 0x61: w = (ws ? "7" : "2008_R2"); break;
  			case 0x62: w = (ws ? "8" : "2012"); break;
  			case 0x63: w = (ws ? "8.1": "2012_R2"); break;
  			case 0x64: w = (ws ? "10": "2015"); break;
  			default:
  				if (windows_version < 0x50)
  					windows_version = WINDOWS_UNSUPPORTED;
  				else
  					w = "11 or later";
  				break;
  			}
  		}
  	}
  
  	if (is_x64())
  		w64 = "64-bit";
  
  	vptr = &windows_version_str[sizeof("Windows ") - 1];
  	vlen = sizeof(windows_version_str) - sizeof("Windows ") - 1;
  	if (!w)
  		safe_sprintf(vptr, vlen, "%s %u.%u %s", (vi.dwPlatformId == VER_PLATFORM_WIN32_NT ? "NT" : "??"),
  			(unsigned int)vi.dwMajorVersion, (unsigned int)vi.dwMinorVersion, w64);
  	else if (vi.wServicePackMinor)
  		safe_sprintf(vptr, vlen, "%s SP%u.%u %s", w, vi.wServicePackMajor, vi.wServicePackMinor, w64);
  	else if (vi.wServicePackMajor)
  		safe_sprintf(vptr, vlen, "%s SP%u %s", w, vi.wServicePackMajor, w64);
  	else
  		safe_sprintf(vptr, vlen, "%s %s", w, w64);
  }
  
  /*
   * init: libusb backend init function
   *
   * This function enumerates the HCDs (Host Controller Drivers) and populates our private HCD list
   * In our implementation, we equate Windows' "HCD" to libusb's "bus". Note that bus is zero indexed.
   * HCDs are not expected to change after init (might not hold true for hot pluggable USB PCI card?)
   */
  static int windows_init(struct libusb_context *ctx)
  {
  	int i, r = LIBUSB_ERROR_OTHER;
  	HANDLE semaphore;
  	char sem_name[11 + 8 + 1]; // strlen("libusb_init") + (32-bit hex PID) + '\0'
  
  	sprintf(sem_name, "libusb_init%08X", (unsigned int)(GetCurrentProcessId() & 0xFFFFFFFF));
  	semaphore = CreateSemaphoreA(NULL, 1, 1, sem_name);
  	if (semaphore == NULL) {
  		usbi_err(ctx, "could not create semaphore: %s", windows_error_str(0));
  		return LIBUSB_ERROR_NO_MEM;
  	}
  
  	// A successful wait brings our semaphore count to 0 (unsignaled)
  	// => any concurent wait stalls until the semaphore's release
  	if (WaitForSingleObject(semaphore, INFINITE) != WAIT_OBJECT_0) {
  		usbi_err(ctx, "failure to access semaphore: %s", windows_error_str(0));
  		CloseHandle(semaphore);
  		return LIBUSB_ERROR_NO_MEM;
  	}
  
  	// NB: concurrent usage supposes that init calls are equally balanced with
  	// exit calls. If init is called more than exit, we will not exit properly
  	if (++concurrent_usage == 0) { // First init?
  		get_windows_version();
  		usbi_dbg(windows_version_str);
  
  		if (windows_version == WINDOWS_UNSUPPORTED) {
  			usbi_err(ctx, "This version of Windows is NOT supported");
  			r = LIBUSB_ERROR_NOT_SUPPORTED;
  			goto init_exit;
  		}
  
  		// We need a lock for proper auto-release
  		usbi_mutex_init(&autoclaim_lock);
  
  		// Initialize pollable file descriptors
  		init_polling();
  
  		// Load DLL imports
  		if (init_dlls() != LIBUSB_SUCCESS) {
  			usbi_err(ctx, "could not resolve DLL functions");
  			goto init_exit;
  		}
  
  		// Initialize the low level APIs (we don't care about errors at this stage)
  		for (i = 0; i < USB_API_MAX; i++)
  			usb_api_backend[i].init(SUB_API_NOTSET, ctx);
  
  		r = windows_common_init(ctx);
  		if (r)
  			goto init_exit;
  	}
  	// At this stage, either we went through full init successfully, or didn't need to
  	r = LIBUSB_SUCCESS;
  
  init_exit: // Holds semaphore here.
  	if (!concurrent_usage && r != LIBUSB_SUCCESS) { // First init failed?
  		for (i = 0; i < USB_API_MAX; i++)
  			usb_api_backend[i].exit(SUB_API_NOTSET);
  		exit_dlls();
  		exit_polling();
  		windows_common_exit();
  		usbi_mutex_destroy(&autoclaim_lock);
  	}
  
  	if (r != LIBUSB_SUCCESS)
  		--concurrent_usage; // Not expected to call libusb_exit if we failed.
  
  	ReleaseSemaphore(semaphore, 1, NULL); // increase count back to 1
  	CloseHandle(semaphore);
  	return r;
  }
  
  /*
   * HCD (root) hubs need to have their device descriptor manually populated
   *
   * Note that, like Microsoft does in the device manager, we populate the
   * Vendor and Device ID for HCD hubs with the ones from the PCI HCD device.
   */
  static int force_hcd_device_descriptor(struct libusb_device *dev)
  {
  	struct windows_device_priv *parent_priv, *priv = _device_priv(dev);
  	struct libusb_context *ctx = DEVICE_CTX(dev);
  	int vid, pid;
  
  	dev->num_configurations = 1;
  	priv->dev_descriptor.bLength = sizeof(USB_DEVICE_DESCRIPTOR);
  	priv->dev_descriptor.bDescriptorType = USB_DEVICE_DESCRIPTOR_TYPE;
  	priv->dev_descriptor.bNumConfigurations = 1;
  	priv->active_config = 1;
  
  	if (dev->parent_dev == NULL) {
  		usbi_err(ctx, "program assertion failed - HCD hub has no parent");
  		return LIBUSB_ERROR_NO_DEVICE;
  	}
  
  	parent_priv = _device_priv(dev->parent_dev);
  	if (sscanf(parent_priv->path, "\\\\.\\PCI#VEN_%04x&DEV_%04x%*s", &vid, &pid) == 2) {
  		priv->dev_descriptor.idVendor = (uint16_t)vid;
  		priv->dev_descriptor.idProduct = (uint16_t)pid;
  	} else {
  		usbi_warn(ctx, "could not infer VID/PID of HCD hub from '%s'", parent_priv->path);
  		priv->dev_descriptor.idVendor = 0x1d6b; // Linux Foundation root hub
  		priv->dev_descriptor.idProduct = 1;
  	}
  
  	return LIBUSB_SUCCESS;
  }
  
  /*
   * fetch and cache all the config descriptors through I/O
   */
  static int cache_config_descriptors(struct libusb_device *dev, HANDLE hub_handle, char *device_id)
  {
  	DWORD size, ret_size;
  	struct libusb_context *ctx = DEVICE_CTX(dev);
  	struct windows_device_priv *priv = _device_priv(dev);
  	int r;
  	uint8_t i;
  
  	USB_CONFIGURATION_DESCRIPTOR_SHORT cd_buf_short; // dummy request
  	PUSB_DESCRIPTOR_REQUEST cd_buf_actual = NULL;    // actual request
  	PUSB_CONFIGURATION_DESCRIPTOR cd_data = NULL;
  
  	if (dev->num_configurations == 0)
  		return LIBUSB_ERROR_INVALID_PARAM;
  
  	priv->config_descriptor = calloc(dev->num_configurations, sizeof(unsigned char *));
  	if (priv->config_descriptor == NULL)
  		return LIBUSB_ERROR_NO_MEM;
  
  	for (i = 0; i < dev->num_configurations; i++)
  		priv->config_descriptor[i] = NULL;
  
  	for (i = 0, r = LIBUSB_SUCCESS; ; i++) {
  		// safe loop: release all dynamic resources
  		safe_free(cd_buf_actual);
  
  		// safe loop: end of loop condition
  		if ((i >= dev->num_configurations) || (r != LIBUSB_SUCCESS))
  			break;
  
  		size = sizeof(USB_CONFIGURATION_DESCRIPTOR_SHORT);
  		memset(&cd_buf_short, 0, size);
  
  		cd_buf_short.req.ConnectionIndex = (ULONG)priv->port;
  		cd_buf_short.req.SetupPacket.bmRequest = LIBUSB_ENDPOINT_IN;
  		cd_buf_short.req.SetupPacket.bRequest = USB_REQUEST_GET_DESCRIPTOR;
  		cd_buf_short.req.SetupPacket.wValue = (USB_CONFIGURATION_DESCRIPTOR_TYPE << 8) | i;
  		cd_buf_short.req.SetupPacket.wIndex = 0;
  		cd_buf_short.req.SetupPacket.wLength = (USHORT)(size - sizeof(USB_DESCRIPTOR_REQUEST));
  
  		// Dummy call to get the required data size. Initial failures are reported as info rather
  		// than error as they can occur for non-penalizing situations, such as with some hubs.
  		// coverity[tainted_data_argument]
  		if (!DeviceIoControl(hub_handle, IOCTL_USB_GET_DESCRIPTOR_FROM_NODE_CONNECTION, &cd_buf_short, size,
  			&cd_buf_short, size, &ret_size, NULL)) {
  			usbi_info(ctx, "could not access configuration descriptor (dummy) for '%s': %s", device_id, windows_error_str(0));
  			LOOP_BREAK(LIBUSB_ERROR_IO);
  		}
  
  		if ((ret_size != size) || (cd_buf_short.data.wTotalLength < sizeof(USB_CONFIGURATION_DESCRIPTOR))) {
  			usbi_info(ctx, "unexpected configuration descriptor size (dummy) for '%s'.", device_id);
  			LOOP_BREAK(LIBUSB_ERROR_IO);
  		}
  
  		size = sizeof(USB_DESCRIPTOR_REQUEST) + cd_buf_short.data.wTotalLength;
  		cd_buf_actual = calloc(1, size);
  		if (cd_buf_actual == NULL) {
  			usbi_err(ctx, "could not allocate configuration descriptor buffer for '%s'.", device_id);
  			LOOP_BREAK(LIBUSB_ERROR_NO_MEM);
  		}
  
  		// Actual call
  		cd_buf_actual->ConnectionIndex = (ULONG)priv->port;
  		cd_buf_actual->SetupPacket.bmRequest = LIBUSB_ENDPOINT_IN;
  		cd_buf_actual->SetupPacket.bRequest = USB_REQUEST_GET_DESCRIPTOR;
  		cd_buf_actual->SetupPacket.wValue = (USB_CONFIGURATION_DESCRIPTOR_TYPE << 8) | i;
  		cd_buf_actual->SetupPacket.wIndex = 0;
  		cd_buf_actual->SetupPacket.wLength = (USHORT)(size - sizeof(USB_DESCRIPTOR_REQUEST));
  
  		if (!DeviceIoControl(hub_handle, IOCTL_USB_GET_DESCRIPTOR_FROM_NODE_CONNECTION, cd_buf_actual, size,
  			cd_buf_actual, size, &ret_size, NULL)) {
  			usbi_err(ctx, "could not access configuration descriptor (actual) for '%s': %s", device_id, windows_error_str(0));
  			LOOP_BREAK(LIBUSB_ERROR_IO);
  		}
  
  		cd_data = (PUSB_CONFIGURATION_DESCRIPTOR)((UCHAR *)cd_buf_actual + sizeof(USB_DESCRIPTOR_REQUEST));
  
  		if ((size != ret_size) || (cd_data->wTotalLength != cd_buf_short.data.wTotalLength)) {
  			usbi_err(ctx, "unexpected configuration descriptor size (actual) for '%s'.", device_id);
  			LOOP_BREAK(LIBUSB_ERROR_IO);
  		}
  
  		if (cd_data->bDescriptorType != USB_CONFIGURATION_DESCRIPTOR_TYPE) {
  			usbi_err(ctx, "not a configuration descriptor for '%s'", device_id);
  			LOOP_BREAK(LIBUSB_ERROR_IO);
  		}
  
  		usbi_dbg("cached config descriptor %d (bConfigurationValue=%u, %u bytes)",
  			i, cd_data->bConfigurationValue, cd_data->wTotalLength);
  
  		// Cache the descriptor
  		priv->config_descriptor[i] = malloc(cd_data->wTotalLength);
  		if (priv->config_descriptor[i] == NULL)
  			LOOP_BREAK(LIBUSB_ERROR_NO_MEM);
  		memcpy(priv->config_descriptor[i], cd_data, cd_data->wTotalLength);
  	}
  	return LIBUSB_SUCCESS;
  }
  
  /*
   * Populate a libusb device structure
   */
  static int init_device(struct libusb_device *dev, struct libusb_device *parent_dev,
  	uint8_t port_number, char *device_id, DWORD devinst)
  {
  	HANDLE handle;
  	DWORD size;
  	USB_NODE_CONNECTION_INFORMATION_EX conn_info;
  	USB_NODE_CONNECTION_INFORMATION_EX_V2 conn_info_v2;
  	struct windows_device_priv *priv, *parent_priv;
  	struct libusb_context *ctx;
  	struct libusb_device *tmp_dev;
  	unsigned long tmp_id;
  	unsigned i;
  
  	if ((dev == NULL) || (parent_dev == NULL))
  		return LIBUSB_ERROR_NOT_FOUND;
  
  	ctx = DEVICE_CTX(dev);
  	priv = _device_priv(dev);
  	parent_priv = _device_priv(parent_dev);
  	if (parent_priv->apib->id != USB_API_HUB) {
  		usbi_warn(ctx, "parent for device '%s' is not a hub", device_id);
  		return LIBUSB_ERROR_NOT_FOUND;
  	}
  
  	// It is possible for the parent hub not to have been initialized yet
  	// If that's the case, lookup the ancestors to set the bus number
  	if (parent_dev->bus_number == 0) {
  		for (i = 2; ; i++) {
  			tmp_id = get_ancestor_session_id(devinst, i);
  			if (tmp_id == 0)
  				break;
  
  			tmp_dev = usbi_get_device_by_session_id(ctx, tmp_id);
  			if (tmp_dev == NULL)
  				continue;
  
  			if (tmp_dev->bus_number != 0) {
  				usbi_dbg("got bus number from ancestor #%u", i);
  				parent_dev->bus_number = tmp_dev->bus_number;
  				libusb_unref_device(tmp_dev);
  				break;
  			}
  
  			libusb_unref_device(tmp_dev);
  		}
  	}
  
  	if (parent_dev->bus_number == 0) {
  		usbi_err(ctx, "program assertion failed: unable to find ancestor bus number for '%s'", device_id);
  		return LIBUSB_ERROR_NOT_FOUND;
  	}
  
  	dev->bus_number = parent_dev->bus_number;
  	priv->port = port_number;
  	dev->port_number = port_number;
  	priv->depth = parent_priv->depth + 1;
  	dev->parent_dev = parent_dev;
  
  	// If the device address is already set, we can stop here
  	if (dev->device_address != 0)
  		return LIBUSB_SUCCESS;
  
  	memset(&conn_info, 0, sizeof(conn_info));
  	if (priv->depth != 0) { // Not a HCD hub
  		handle = CreateFileA(parent_priv->path, GENERIC_WRITE, FILE_SHARE_WRITE, NULL, OPEN_EXISTING,
  			FILE_FLAG_OVERLAPPED, NULL);
  		if (handle == INVALID_HANDLE_VALUE) {
  			usbi_warn(ctx, "could not open hub %s: %s", parent_priv->path, windows_error_str(0));
  			return LIBUSB_ERROR_ACCESS;
  		}
  
  		size = sizeof(conn_info);
  		conn_info.ConnectionIndex = (ULONG)port_number;
  		// coverity[tainted_data_argument]
  		if (!DeviceIoControl(handle, IOCTL_USB_GET_NODE_CONNECTION_INFORMATION_EX, &conn_info, size,
  			&conn_info, size, &size, NULL)) {
  			usbi_warn(ctx, "could not get node connection information for device '%s': %s",
  				device_id, windows_error_str(0));
  			safe_closehandle(handle);
  			return LIBUSB_ERROR_NO_DEVICE;
  		}
  
  		if (conn_info.ConnectionStatus == NoDeviceConnected) {
  			usbi_err(ctx, "device '%s' is no longer connected!", device_id);
  			safe_closehandle(handle);
  			return LIBUSB_ERROR_NO_DEVICE;
  		}
  
  		memcpy(&priv->dev_descriptor, &(conn_info.DeviceDescriptor), sizeof(USB_DEVICE_DESCRIPTOR));
  		dev->num_configurations = priv->dev_descriptor.bNumConfigurations;
  		priv->active_config = conn_info.CurrentConfigurationValue;
  		usbi_dbg("found %u configurations (active conf: %u)", dev->num_configurations, priv->active_config);
  
  		// If we can't read the config descriptors, just set the number of confs to zero
  		if (cache_config_descriptors(dev, handle, device_id) != LIBUSB_SUCCESS) {
  			dev->num_configurations = 0;
  			priv->dev_descriptor.bNumConfigurations = 0;
  		}
  
  		// In their great wisdom, Microsoft decided to BREAK the USB speed report between Windows 7 and Windows 8
  		if (windows_version >= WINDOWS_8) {
  			memset(&conn_info_v2, 0, sizeof(conn_info_v2));
  			size = sizeof(conn_info_v2);
  			conn_info_v2.ConnectionIndex = (ULONG)port_number;
  			conn_info_v2.Length = size;
  			conn_info_v2.SupportedUsbProtocols.Usb300 = 1;
  			if (!DeviceIoControl(handle, IOCTL_USB_GET_NODE_CONNECTION_INFORMATION_EX_V2,
  				&conn_info_v2, size, &conn_info_v2, size, &size, NULL)) {
  				usbi_warn(ctx, "could not get node connection information (V2) for device '%s': %s",
  					device_id,  windows_error_str(0));
  			} else if (conn_info_v2.Flags.DeviceIsOperatingAtSuperSpeedOrHigher) {
  				conn_info.Speed = 3;
  			}
  		}
  
  		safe_closehandle(handle);
  
  		if (conn_info.DeviceAddress > UINT8_MAX)
  			usbi_err(ctx, "program assertion failed: device address overflow");
  
  		dev->device_address = (uint8_t)conn_info.DeviceAddress + 1;
  		if (dev->device_address == 1)
  			usbi_err(ctx, "program assertion failed: device address collision with root hub");
  
  		switch (conn_info.Speed) {
  		case 0: dev->speed = LIBUSB_SPEED_LOW; break;
  		case 1: dev->speed = LIBUSB_SPEED_FULL; break;
  		case 2: dev->speed = LIBUSB_SPEED_HIGH; break;
  		case 3: dev->speed = LIBUSB_SPEED_SUPER; break;
  		default:
  			usbi_warn(ctx, "Got unknown device speed %u", conn_info.Speed);
  			break;
  		}
  	} else {
  		dev->device_address = 1; // root hubs are set to use device number 1
  		force_hcd_device_descriptor(dev);
  	}
  
  	usbi_sanitize_device(dev);
  
  	usbi_dbg("(bus: %u, addr: %u, depth: %u, port: %u): '%s'",
  		dev->bus_number, dev->device_address, priv->depth, priv->port, device_id);
  
  	return LIBUSB_SUCCESS;
  }
  
  // Returns the api type, or 0 if not found/unsupported
  static void get_api_type(struct libusb_context *ctx, HDEVINFO *dev_info,
  	SP_DEVINFO_DATA *dev_info_data, int *api, int *sub_api)
  {
  	// Precedence for filter drivers vs driver is in the order of this array
  	struct driver_lookup lookup[3] = {
  		{"\0\0", SPDRP_SERVICE, "driver"},
  		{"\0\0", SPDRP_UPPERFILTERS, "upper filter driver"},
  		{"\0\0", SPDRP_LOWERFILTERS, "lower filter driver"}
  	};
  	DWORD size, reg_type;
  	unsigned k, l;
  	int i, j;
  
  	*api = USB_API_UNSUPPORTED;
  	*sub_api = SUB_API_NOTSET;
  
  	// Check the service & filter names to know the API we should use
  	for (k = 0; k < 3; k++) {
  		if (pSetupDiGetDeviceRegistryPropertyA(*dev_info, dev_info_data, lookup[k].reg_prop,
  			&reg_type, (BYTE *)lookup[k].list, MAX_KEY_LENGTH, &size)) {
  			// Turn the REG_SZ SPDRP_SERVICE into REG_MULTI_SZ
  			if (lookup[k].reg_prop == SPDRP_SERVICE)
  				// our buffers are MAX_KEY_LENGTH + 1 so we can overflow if needed
  				lookup[k].list[safe_strlen(lookup[k].list) + 1] = 0;
  
  			// MULTI_SZ is a pain to work with. Turn it into something much more manageable
  			// NB: none of the driver names we check against contain LIST_SEPARATOR,
  			// (currently ';'), so even if an unsuported one does, it's not an issue
  			for (l = 0; (lookup[k].list[l] != 0) || (lookup[k].list[l + 1] != 0); l++) {
  				if (lookup[k].list[l] == 0)
  					lookup[k].list[l] = LIST_SEPARATOR;
  			}
  			usbi_dbg("%s(s): %s", lookup[k].designation, lookup[k].list);
  		} else {
  			if (GetLastError() != ERROR_INVALID_DATA)
  				usbi_dbg("could not access %s: %s", lookup[k].designation, windows_error_str(0));
  			lookup[k].list[0] = 0;
  		}
  	}
  
  	for (i = 1; i < USB_API_MAX; i++) {
  		for (k = 0; k < 3; k++) {
  			j = get_sub_api(lookup[k].list, i);
  			if (j >= 0) {
  				usbi_dbg("matched %s name against %s", lookup[k].designation,
  					(i != USB_API_WINUSBX) ? usb_api_backend[i].designation : sub_api_name[j]);
  				*api = i;
  				*sub_api = j;
  				return;
  			}
  		}
  	}
  }
  
  static int set_composite_interface(struct libusb_context *ctx, struct libusb_device *dev,
  	char *dev_interface_path, char *device_id, int api, int sub_api)
  {
  	unsigned i;
  	struct windows_device_priv *priv = _device_priv(dev);
  	int interface_number;
  
  	if (priv->apib->id != USB_API_COMPOSITE) {
  		usbi_err(ctx, "program assertion failed: '%s' is not composite", device_id);
  		return LIBUSB_ERROR_NO_DEVICE;
  	}
  
  	// Because MI_## are not necessarily in sequential order (some composite
  	// devices will have only MI_00 & MI_03 for instance), we retrieve the actual
  	// interface number from the path's MI value
  	interface_number = 0;
  	for (i = 0; device_id[i] != 0; ) {
  		if ((device_id[i++] == 'M') && (device_id[i++] == 'I')
  				&& (device_id[i++] == '_')) {
  			interface_number = (device_id[i++] - '0') * 10;
  			interface_number += device_id[i] - '0';
  			break;
  		}
  	}
  
  	if (device_id[i] == 0)
  		usbi_warn(ctx, "failure to read interface number for %s. Using default value %d",
  			device_id, interface_number);
  
  	if (priv->usb_interface[interface_number].path != NULL) {
  		if (api == USB_API_HID) {
  			// HID devices can have multiple collections (COL##) for each MI_## interface
  			usbi_dbg("interface[%d] already set - ignoring HID collection: %s",
  				interface_number, device_id);
  			return LIBUSB_ERROR_ACCESS;
  		}
  		// In other cases, just use the latest data
  		safe_free(priv->usb_interface[interface_number].path);
  	}
  
  	usbi_dbg("interface[%d] = %s", interface_number, dev_interface_path);
  	priv->usb_interface[interface_number].path = dev_interface_path;
  	priv->usb_interface[interface_number].apib = &usb_api_backend[api];
  	priv->usb_interface[interface_number].sub_api = sub_api;
  	if ((api == USB_API_HID) && (priv->hid == NULL)) {
  		priv->hid = calloc(1, sizeof(struct hid_device_priv));
  		if (priv->hid == NULL)
  			return LIBUSB_ERROR_NO_MEM;
  	}
  
  	return LIBUSB_SUCCESS;
  }
  
  static int set_hid_interface(struct libusb_context *ctx, struct libusb_device *dev,
  	char *dev_interface_path)
  {
  	int i;
  	struct windows_device_priv *priv = _device_priv(dev);
  
  	if (priv->hid == NULL) {
  		usbi_err(ctx, "program assertion failed: parent is not HID");
  		return LIBUSB_ERROR_NO_DEVICE;
  	} else if (priv->hid->nb_interfaces == USB_MAXINTERFACES) {
  		usbi_err(ctx, "program assertion failed: max USB interfaces reached for HID device");
  		return LIBUSB_ERROR_NO_DEVICE;
  	}
  
  	for (i = 0; i < priv->hid->nb_interfaces; i++) {
  		if (safe_strcmp(priv->usb_interface[i].path, dev_interface_path) == 0) {
  			usbi_dbg("interface[%d] already set to %s", i, dev_interface_path);
  			return LIBUSB_ERROR_ACCESS;
  		}
  	}
  
  	priv->usb_interface[priv->hid->nb_interfaces].path = dev_interface_path;
  	priv->usb_interface[priv->hid->nb_interfaces].apib = &usb_api_backend[USB_API_HID];
  	usbi_dbg("interface[%u] = %s", priv->hid->nb_interfaces, dev_interface_path);
  	priv->hid->nb_interfaces++;
  	return LIBUSB_SUCCESS;
  }
  
  /*
   * get_device_list: libusb backend device enumeration function
   */
  static int windows_get_device_list(struct libusb_context *ctx, struct discovered_devs **_discdevs)
  {
  	struct discovered_devs *discdevs;
  	HDEVINFO dev_info = { 0 };
  	const char *usb_class[] = {"USB", "NUSB3", "IUSB3", "IARUSB3"};
  	SP_DEVINFO_DATA dev_info_data = { 0 };
  	SP_DEVICE_INTERFACE_DETAIL_DATA_A *dev_interface_details = NULL;
  	GUID hid_guid;
  #define MAX_ENUM_GUIDS 64
  	const GUID *guid[MAX_ENUM_GUIDS];
  #define HCD_PASS 0
  #define HUB_PASS 1
  #define GEN_PASS 2
  #define DEV_PASS 3
  #define HID_PASS 4
  	int r = LIBUSB_SUCCESS;
  	int api, sub_api;
  	size_t class_index = 0;
  	unsigned int nb_guids, pass, i, j, ancestor;
  	char path[MAX_PATH_LENGTH];
  	char strbuf[MAX_PATH_LENGTH];
  	struct libusb_device *dev, *parent_dev;
  	struct windows_device_priv *priv, *parent_priv;
  	char *dev_interface_path = NULL;
  	char *dev_id_path = NULL;
  	unsigned long session_id;
  	DWORD size, reg_type, port_nr, install_state;
  	HKEY key;
  	WCHAR guid_string_w[MAX_GUID_STRING_LENGTH];
  	GUID *if_guid;
  	LONG s;
  	// Keep a list of newly allocated devs to unref
  	libusb_device **unref_list, **new_unref_list;
  	unsigned int unref_size = 64;
  	unsigned int unref_cur = 0;
  
  	// PASS 1 : (re)enumerate HCDs (allows for HCD hotplug)
  	// PASS 2 : (re)enumerate HUBS
  	// PASS 3 : (re)enumerate generic USB devices (including driverless)
  	//           and list additional USB device interface GUIDs to explore
  	// PASS 4 : (re)enumerate master USB devices that have a device interface
  	// PASS 5+: (re)enumerate device interfaced GUIDs (including HID) and
  	//           set the device interfaces.
  
  	// Init the GUID table
  	guid[HCD_PASS] = &GUID_DEVINTERFACE_USB_HOST_CONTROLLER;
  	guid[HUB_PASS] = &GUID_DEVINTERFACE_USB_HUB;
  	guid[GEN_PASS] = NULL;
  	guid[DEV_PASS] = &GUID_DEVINTERFACE_USB_DEVICE;
  	HidD_GetHidGuid(&hid_guid);
  	guid[HID_PASS] = &hid_guid;
  	nb_guids = HID_PASS + 1;
  
  	unref_list = calloc(unref_size, sizeof(libusb_device *));
  	if (unref_list == NULL)
  		return LIBUSB_ERROR_NO_MEM;
  
  	for (pass = 0; ((pass < nb_guids) && (r == LIBUSB_SUCCESS)); pass++) {
  //#define ENUM_DEBUG
  #if defined(ENABLE_LOGGING) && defined(ENUM_DEBUG)
  		const char *passname[] = { "HCD", "HUB", "GEN", "DEV", "HID", "EXT" };
  		usbi_dbg("#### PROCESSING %ss %s", passname[(pass <= HID_PASS) ? pass : (HID_PASS + 1)],
  			(pass != GEN_PASS) ? guid_to_string(guid[pass]) : "");
  #endif
  		for (i = 0; ; i++) {
  			// safe loop: free up any (unprotected) dynamic resource
  			// NB: this is always executed before breaking the loop
  			safe_free(dev_interface_details);
  			safe_free(dev_interface_path);
  			safe_free(dev_id_path);
  			priv = parent_priv = NULL;
  			dev = parent_dev = NULL;
  
  			// Safe loop: end of loop conditions
  			if (r != LIBUSB_SUCCESS)
  				break;
  
  			if ((pass == HCD_PASS) && (i == UINT8_MAX)) {
  				usbi_warn(ctx, "program assertion failed - found more than %d buses, skipping the rest.", UINT8_MAX);
  				break;
  			}
  
  			if (pass != GEN_PASS) {
  				// Except for GEN, all passes deal with device interfaces
  				dev_interface_details = get_interface_details(ctx, &dev_info, &dev_info_data, guid[pass], i);
  				if (dev_interface_details == NULL)
  					break;
  
  				dev_interface_path = sanitize_path(dev_interface_details->DevicePath);
  				if (dev_interface_path == NULL) {
  					usbi_warn(ctx, "could not sanitize device interface path for '%s'", dev_interface_details->DevicePath);
  					continue;
  				}
  			} else {
  				// Workaround for a Nec/Renesas USB 3.0 driver bug where root hubs are
  				// being listed under the "NUSB3" PnP Symbolic Name rather than "USB".
  				// The Intel USB 3.0 driver behaves similar, but uses "IUSB3"
  				// The Intel Alpine Ridge USB 3.1 driver uses "IARUSB3"
  				for (; class_index < ARRAYSIZE(usb_class); class_index++) {
  					if (get_devinfo_data(ctx, &dev_info, &dev_info_data, usb_class[class_index], i))
  						break;
  					i = 0;
  				}
  				if (class_index >= ARRAYSIZE(usb_class))
  					break;
  			}
  
  			// Read the Device ID path. This is what we'll use as UID
  			// Note that if the device is plugged in a different port or hub, the Device ID changes
  			if (CM_Get_Device_IDA(dev_info_data.DevInst, path, sizeof(path), 0) != CR_SUCCESS) {
  				usbi_warn(ctx, "could not read the device id path for devinst %X, skipping",
  					(unsigned int)dev_info_data.DevInst);
  				continue;
  			}
  
  			dev_id_path = sanitize_path(path);
  			if (dev_id_path == NULL) {
  				usbi_warn(ctx, "could not sanitize device id path for devinst %X, skipping",
  					(unsigned int)dev_info_data.DevInst);
  				continue;
  			}
  #ifdef ENUM_DEBUG
  			usbi_dbg("PRO: %s", dev_id_path);
  #endif
  
  			// The SPDRP_ADDRESS for USB devices is the device port number on the hub
  			port_nr = 0;
  			if ((pass >= HUB_PASS) && (pass <= GEN_PASS)) {
  				if ((!pSetupDiGetDeviceRegistryPropertyA(dev_info, &dev_info_data, SPDRP_ADDRESS,
  					&reg_type, (BYTE *)&port_nr, 4, &size)) || (size != 4)) {
  					usbi_warn(ctx, "could not retrieve port number for device '%s', skipping: %s",
  						dev_id_path, windows_error_str(0));
  					continue;
  				}
  			}
  
  			// Set API to use or get additional data from generic pass
  			api = USB_API_UNSUPPORTED;
  			sub_api = SUB_API_NOTSET;
  			switch (pass) {
  			case HCD_PASS:
  				break;
  			case GEN_PASS:
  				// We use the GEN pass to detect driverless devices...
  				size = sizeof(strbuf);
  				if (!pSetupDiGetDeviceRegistryPropertyA(dev_info, &dev_info_data, SPDRP_DRIVER,
  					&reg_type, (BYTE *)strbuf, size, &size)) {
  						usbi_info(ctx, "The following device has no driver: '%s'", dev_id_path);
  						usbi_info(ctx, "libusb will not be able to access it.");
  				}
  				// ...and to add the additional device interface GUIDs
  				key = pSetupDiOpenDevRegKey(dev_info, &dev_info_data, DICS_FLAG_GLOBAL, 0, DIREG_DEV, KEY_READ);
  				if (key != INVALID_HANDLE_VALUE) {
  					size = sizeof(guid_string_w);
  					s = pRegQueryValueExW(key, L"DeviceInterfaceGUIDs", NULL, &reg_type,
  						(BYTE *)guid_string_w, &size);
  					pRegCloseKey(key);
  					if (s == ERROR_SUCCESS) {
  						if (nb_guids >= MAX_ENUM_GUIDS) {
  							// If this assert is ever reported, grow a GUID table dynamically
  							usbi_err(ctx, "program assertion failed: too many GUIDs");
  							LOOP_BREAK(LIBUSB_ERROR_OVERFLOW);
  						}
  						if_guid = calloc(1, sizeof(GUID));
  						if (if_guid == NULL) {
  							usbi_err(ctx, "could not calloc for if_guid: not enough memory");
  							LOOP_BREAK(LIBUSB_ERROR_NO_MEM);
  						}
  						pCLSIDFromString(guid_string_w, if_guid);
  						guid[nb_guids++] = if_guid;
  						usbi_dbg("extra GUID: %s", guid_to_string(if_guid));
  					}
  				}
  				break;
  			case HID_PASS:
  				api = USB_API_HID;
  				break;
  			default:
  				// Get the API type (after checking that the driver installation is OK)
  				if ((!pSetupDiGetDeviceRegistryPropertyA(dev_info, &dev_info_data, SPDRP_INSTALL_STATE,
  					&reg_type, (BYTE *)&install_state, 4, &size)) || (size != 4)) {
  					usbi_warn(ctx, "could not detect installation state of driver for '%s': %s",
  						dev_id_path, windows_error_str(0));
  				} else if (install_state != 0) {
  					usbi_warn(ctx, "driver for device '%s' is reporting an issue (code: %u) - skipping",
  						dev_id_path, (unsigned int)install_state);
  					continue;
  				}
  				get_api_type(ctx, &dev_info, &dev_info_data, &api, &sub_api);
  				break;
  			}
  
  			// Find parent device (for the passes that need it)
  			switch (pass) {
  			case HCD_PASS:
  			case DEV_PASS:
  			case HUB_PASS:
  				break;
  			default:
  				// Go through the ancestors until we see a face we recognize
  				parent_dev = NULL;
  				for (ancestor = 1; parent_dev == NULL; ancestor++) {
  					session_id = get_ancestor_session_id(dev_info_data.DevInst, ancestor);
  					if (session_id == 0)
  						break;
  
  					parent_dev = usbi_get_device_by_session_id(ctx, session_id);
  				}
  
  				if (parent_dev == NULL) {
  					usbi_dbg("unlisted ancestor for '%s' (non USB HID, newly connected, etc.) - ignoring", dev_id_path);
  					continue;
  				}
  
  				parent_priv = _device_priv(parent_dev);
  				// virtual USB devices are also listed during GEN - don't process these yet
  				if ((pass == GEN_PASS) && (parent_priv->apib->id != USB_API_HUB)) {
  					libusb_unref_device(parent_dev);
  					continue;
  				}
  
  				break;
  			}
  
  			// Create new or match existing device, using the (hashed) device_id as session id
  			if (pass <= DEV_PASS) {	// For subsequent passes, we'll lookup the parent
  				// These are the passes that create "new" devices
  				session_id = htab_hash(dev_id_path);
  				dev = usbi_get_device_by_session_id(ctx, session_id);
  				if (dev == NULL) {
  					if (pass == DEV_PASS) {
  						// This can occur if the OS only reports a newly plugged device after we started enum
  						usbi_warn(ctx, "'%s' was only detected in late pass (newly connected device?)"
  							" - ignoring", dev_id_path);
  						continue;
  					}
  
  					usbi_dbg("allocating new device for session [%lX]", session_id);
  					dev = usbi_alloc_device(ctx, session_id);
  					if (dev == NULL)
  						LOOP_BREAK(LIBUSB_ERROR_NO_MEM);
  
  					priv = windows_device_priv_init(dev);
  				} else {
  					usbi_dbg("found existing device for session [%lX] (%u.%u)",
  						session_id, dev->bus_number, dev->device_address);
  
  					priv = _device_priv(dev);
  					if ((parent_dev != NULL) && (dev->parent_dev != NULL)) {
  						if (dev->parent_dev != parent_dev) {
  							// It is possible for the actual parent device to not have existed at the
  							// time of enumeration, so the currently assigned parent may in fact be a
  							// grandparent.  If the devices differ, we assume the "new" parent device
  							// is in fact closer to the device.
                                                          usbi_dbg("updating parent device [session %lX -> %lX]",
                                                                  dev->parent_dev->session_data, parent_dev->session_data);
  							libusb_unref_device(dev->parent_dev);
  							dev->parent_dev = parent_dev;
  						} else {
  							// We hold a reference to parent_dev instance, but this device already
  							// has a parent_dev reference (only one per child)
  							libusb_unref_device(parent_dev);
  						}
  					}
  				}
  
  				// Keep track of devices that need unref
  				unref_list[unref_cur++] = dev;
  				if (unref_cur >= unref_size) {
  					unref_size += 64;
  					new_unref_list = usbi_reallocf(unref_list, unref_size * sizeof(libusb_device *));
  					if (new_unref_list == NULL) {
  						usbi_err(ctx, "could not realloc list for unref - aborting.");
  						LOOP_BREAK(LIBUSB_ERROR_NO_MEM);
  					} else {
  						unref_list = new_unref_list;
  					}
  				}
  			}
  
  			// Setup device
  			switch (pass) {
  			case HCD_PASS:
  				// If the hcd has already been setup, don't do it again
  				if (priv->path != NULL)
  					break;
  				dev->bus_number = (uint8_t)(i + 1); // bus 0 is reserved for disconnected
  				dev->device_address = 0;
  				dev->num_configurations = 0;
  				priv->apib = &usb_api_backend[USB_API_HUB];
  				priv->sub_api = SUB_API_NOTSET;
  				priv->depth = UINT8_MAX; // Overflow to 0 for HCD Hubs
  				priv->path = dev_interface_path;
  				dev_interface_path = NULL;
  				break;
  			case HUB_PASS:
  			case DEV_PASS:
  				// If the device has already been setup, don't do it again
  				if (priv->path != NULL)
  					break;
  				// Take care of API initialization
  				priv->path = dev_interface_path;
  				dev_interface_path = NULL;
  				priv->apib = &usb_api_backend[api];
  				priv->sub_api = sub_api;
  				switch(api) {
  				case USB_API_COMPOSITE:
  				case USB_API_HUB:
  					break;
  				case USB_API_HID:
  					priv->hid = calloc(1, sizeof(struct hid_device_priv));
  					if (priv->hid == NULL)
  						LOOP_BREAK(LIBUSB_ERROR_NO_MEM);
  
  					priv->hid->nb_interfaces = 0;
  					break;
  				default:
  					// For other devices, the first interface is the same as the device
  					priv->usb_interface[0].path = _strdup(priv->path);
  					if (priv->usb_interface[0].path == NULL)
  						usbi_warn(ctx, "could not duplicate interface path '%s'", priv->path);
  					// The following is needed if we want API calls to work for both simple
  					// and composite devices.
  					for(j = 0; j < USB_MAXINTERFACES; j++)
  						priv->usb_interface[j].apib = &usb_api_backend[api];
  
  					break;
  				}
  				break;
  			case GEN_PASS:
  				r = init_device(dev, parent_dev, (uint8_t)port_nr, dev_id_path, dev_info_data.DevInst);
  				if (r == LIBUSB_SUCCESS) {
  					// Append device to the list of discovered devices
  					discdevs = discovered_devs_append(*_discdevs, dev);
  					if (!discdevs)
  						LOOP_BREAK(LIBUSB_ERROR_NO_MEM);
  
  					*_discdevs = discdevs;
  				} else if (r == LIBUSB_ERROR_NO_DEVICE) {
  					// This can occur if the device was disconnected but Windows hasn't
  					// refreshed its enumeration yet - in that case, we ignore the device
  					r = LIBUSB_SUCCESS;
  				}
  				break;
  			default: // HID_PASS and later
  				if (parent_priv->apib->id == USB_API_HID || parent_priv->apib->id == USB_API_COMPOSITE) {
  					if (parent_priv->apib->id == USB_API_HID) {
  						usbi_dbg("setting HID interface for [%lX]:", parent_dev->session_data);
  						r = set_hid_interface(ctx, parent_dev, dev_interface_path);
  					} else {
  						usbi_dbg("setting composite interface for [%lX]:", parent_dev->session_data);
  						r = set_composite_interface(ctx, parent_dev, dev_interface_path, dev_id_path, api, sub_api);
  					}
  					switch (r) {
  					case LIBUSB_SUCCESS:
  						dev_interface_path = NULL;
  						break;
  					case LIBUSB_ERROR_ACCESS:
  						// interface has already been set => make sure dev_interface_path is freed then
  						r = LIBUSB_SUCCESS;
  						break;
  					default:
  						LOOP_BREAK(r);
  						break;
  					}
  				}
  				libusb_unref_device(parent_dev);
  				break;
  			}
  		}
  	}
  
  	// Free any additional GUIDs
  	for (pass = HID_PASS + 1; pass < nb_guids; pass++)
  		safe_free(guid[pass]);
  
  	// Unref newly allocated devs
  	for (i = 0; i < unref_cur; i++)
  		safe_unref_device(unref_list[i]);
  	free(unref_list);
  
  	return r;
  }
  
  /*
   * exit: libusb backend deinitialization function
   */
  static void windows_exit(void)
  {
  	int i;
  	HANDLE semaphore;
  	char sem_name[11 + 8 + 1]; // strlen("libusb_init") + (32-bit hex PID) + '\0'
  
  	sprintf(sem_name, "libusb_init%08X", (unsigned int)(GetCurrentProcessId() & 0xFFFFFFFF));
  	semaphore = CreateSemaphoreA(NULL, 1, 1, sem_name);
  	if (semaphore == NULL)
  		return;
  
  	// A successful wait brings our semaphore count to 0 (unsignaled)
  	// => any concurent wait stalls until the semaphore release
  	if (WaitForSingleObject(semaphore, INFINITE) != WAIT_OBJECT_0) {
  		CloseHandle(semaphore);
  		return;
  	}
  
  	// Only works if exits and inits are balanced exactly
  	if (--concurrent_usage < 0) { // Last exit
  		for (i = 0; i < USB_API_MAX; i++)
  			usb_api_backend[i].exit(SUB_API_NOTSET);
  		exit_dlls();
  		exit_polling();
  		windows_common_exit();
  		usbi_mutex_destroy(&autoclaim_lock);
  	}
  
  	ReleaseSemaphore(semaphore, 1, NULL); // increase count back to 1
  	CloseHandle(semaphore);
  }
  
  static int windows_get_device_descriptor(struct libusb_device *dev, unsigned char *buffer, int *host_endian)
  {
  	struct windows_device_priv *priv = _device_priv(dev);
  
  	memcpy(buffer, &priv->dev_descriptor, DEVICE_DESC_LENGTH);
  	*host_endian = 0;
  
  	return LIBUSB_SUCCESS;
  }
  
  static int windows_get_config_descriptor(struct libusb_device *dev, uint8_t config_index, unsigned char *buffer, size_t len, int *host_endian)
  {
  	struct windows_device_priv *priv = _device_priv(dev);
  	PUSB_CONFIGURATION_DESCRIPTOR config_header;
  	size_t size;
  
  	// config index is zero based
  	if (config_index >= dev->num_configurations)
  		return LIBUSB_ERROR_INVALID_PARAM;
  
  	if ((priv->config_descriptor == NULL) || (priv->config_descriptor[config_index] == NULL))
  		return LIBUSB_ERROR_NOT_FOUND;
  
  	config_header = (PUSB_CONFIGURATION_DESCRIPTOR)priv->config_descriptor[config_index];
  
  	size = MIN(config_header->wTotalLength, len);
  	memcpy(buffer, priv->config_descriptor[config_index], size);
  	*host_endian = 0;
  
  	return (int)size;
  }
  
  static int windows_get_config_descriptor_by_value(struct libusb_device *dev, uint8_t bConfigurationValue,
  	unsigned char **buffer, int *host_endian)
  {
  	struct windows_device_priv *priv = _device_priv(dev);
  	PUSB_CONFIGURATION_DESCRIPTOR config_header;
  	uint8_t index;
  
  	*buffer = NULL;
  	*host_endian = 0;
  
  	if (priv->config_descriptor == NULL)
  		return LIBUSB_ERROR_NOT_FOUND;
  
  	for (index = 0; index < dev->num_configurations; index++) {
  		config_header = (PUSB_CONFIGURATION_DESCRIPTOR)priv->config_descriptor[index];
  		if (config_header->bConfigurationValue == bConfigurationValue) {
  			*buffer = priv->config_descriptor[index];
  			return (int)config_header->wTotalLength;
  		}
  	}
  
  	return LIBUSB_ERROR_NOT_FOUND;
  }
  
  /*
   * return the cached copy of the active config descriptor
   */
  static int windows_get_active_config_descriptor(struct libusb_device *dev, unsigned char *buffer, size_t len, int *host_endian)
  {
  	struct windows_device_priv *priv = _device_priv(dev);
  	unsigned char *config_desc;
  	int r;
  
  	if (priv->active_config == 0)
  		return LIBUSB_ERROR_NOT_FOUND;
  
  	r = windows_get_config_descriptor_by_value(dev, priv->active_config, &config_desc, host_endian);
  	if (r < 0)
  		return r;
  
  	len = MIN((size_t)r, len);
  	memcpy(buffer, config_desc, len);
  	return (int)len;
  }
  
  static int windows_open(struct libusb_device_handle *dev_handle)
  {
  	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
  	struct libusb_context *ctx = DEVICE_CTX(dev_handle->dev);
  
  	if (priv->apib == NULL) {
  		usbi_err(ctx, "program assertion failed - device is not initialized");
  		return LIBUSB_ERROR_NO_DEVICE;
  	}
  
  	return priv->apib->open(SUB_API_NOTSET, dev_handle);
  }
  
  static void windows_close(struct libusb_device_handle *dev_handle)
  {
  	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
  
  	priv->apib->close(SUB_API_NOTSET, dev_handle);
  }
  
  static int windows_get_configuration(struct libusb_device_handle *dev_handle, int *config)
  {
  	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
  
  	if (priv->active_config == 0) {
  		*config = 0;
  		return LIBUSB_ERROR_NOT_FOUND;
  	}
  
  	*config = priv->active_config;
  	return LIBUSB_SUCCESS;
  }
  
  /*
   * from http://msdn.microsoft.com/en-us/library/ms793522.aspx: "The port driver
   * does not currently expose a service that allows higher-level drivers to set
   * the configuration."
   */
  static int windows_set_configuration(struct libusb_device_handle *dev_handle, int config)
  {
  	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
  	int r = LIBUSB_SUCCESS;
  
  	if (config >= USB_MAXCONFIG)
  		return LIBUSB_ERROR_INVALID_PARAM;
  
  	r = libusb_control_transfer(dev_handle, LIBUSB_ENDPOINT_OUT |
  		LIBUSB_REQUEST_TYPE_STANDARD | LIBUSB_RECIPIENT_DEVICE,
  		LIBUSB_REQUEST_SET_CONFIGURATION, (uint16_t)config,
  		0, NULL, 0, 1000);
  
  	if (r == LIBUSB_SUCCESS)
  		priv->active_config = (uint8_t)config;
  
  	return r;
  }
  
  static int windows_claim_interface(struct libusb_device_handle *dev_handle, int iface)
  {
  	int r = LIBUSB_SUCCESS;
  	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
  
  	safe_free(priv->usb_interface[iface].endpoint);
  	priv->usb_interface[iface].nb_endpoints = 0;
  
  	r = priv->apib->claim_interface(SUB_API_NOTSET, dev_handle, iface);
  
  	if (r == LIBUSB_SUCCESS)
  		r = windows_assign_endpoints(dev_handle, iface, 0);
  
  	return r;
  }
  
  static int windows_set_interface_altsetting(struct libusb_device_handle *dev_handle, int iface, int altsetting)
  {
  	int r = LIBUSB_SUCCESS;
  	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
  
  	safe_free(priv->usb_interface[iface].endpoint);
  	priv->usb_interface[iface].nb_endpoints = 0;
  
  	r = priv->apib->set_interface_altsetting(SUB_API_NOTSET, dev_handle, iface, altsetting);
  
  	if (r == LIBUSB_SUCCESS)
  		r = windows_assign_endpoints(dev_handle, iface, altsetting);
  
  	return r;
  }
  
  static int windows_release_interface(struct libusb_device_handle *dev_handle, int iface)
  {
  	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
  
  	return priv->apib->release_interface(SUB_API_NOTSET, dev_handle, iface);
  }
  
  static int windows_clear_halt(struct libusb_device_handle *dev_handle, unsigned char endpoint)
  {
  	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
  	return priv->apib->clear_halt(SUB_API_NOTSET, dev_handle, endpoint);
  }
  
  static int windows_reset_device(struct libusb_device_handle *dev_handle)
  {
  	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
  	return priv->apib->reset_device(SUB_API_NOTSET, dev_handle);
  }
  
  // The 3 functions below are unlikely to ever get supported on Windows
  static int windows_kernel_driver_active(struct libusb_device_handle *dev_handle, int iface)
  {
  	return LIBUSB_ERROR_NOT_SUPPORTED;
  }
  
  static int windows_attach_kernel_driver(struct libusb_device_handle *dev_handle, int iface)
  {
  	return LIBUSB_ERROR_NOT_SUPPORTED;
  }
  
  static int windows_detach_kernel_driver(struct libusb_device_handle *dev_handle, int iface)
  {
  	return LIBUSB_ERROR_NOT_SUPPORTED;
  }
  
  static void windows_destroy_device(struct libusb_device *dev)
  {
  	windows_device_priv_release(dev);
  }
  
  void windows_clear_transfer_priv(struct usbi_transfer *itransfer)
  {
  	struct windows_transfer_priv *transfer_priv = usbi_transfer_get_os_priv(itransfer);
  
  	usbi_free_fd(&transfer_priv->pollable_fd);
  	safe_free(transfer_priv->hid_buffer);
  	// When auto claim is in use, attempt to release the auto-claimed interface
  	auto_release(itransfer);
  }
  
  static int submit_bulk_transfer(struct usbi_transfer *itransfer)
  {
  	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
  	struct libusb_context *ctx = DEVICE_CTX(transfer->dev_handle->dev);
  	struct windows_transfer_priv *transfer_priv = usbi_transfer_get_os_priv(itransfer);
  	struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
  	int r;
  
  	r = priv->apib->submit_bulk_transfer(SUB_API_NOTSET, itransfer);
  	if (r != LIBUSB_SUCCESS)
  		return r;
  
  	usbi_add_pollfd(ctx, transfer_priv->pollable_fd.fd,
  		(short)(IS_XFERIN(transfer) ? POLLIN : POLLOUT));
  
  	return LIBUSB_SUCCESS;
  }
  
  static int submit_iso_transfer(struct usbi_transfer *itransfer)
  {
  	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
  	struct libusb_context *ctx = DEVICE_CTX(transfer->dev_handle->dev);
  	struct windows_transfer_priv *transfer_priv = usbi_transfer_get_os_priv(itransfer);
  	struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
  	int r;
  
  	r = priv->apib->submit_iso_transfer(SUB_API_NOTSET, itransfer);
  	if (r != LIBUSB_SUCCESS)
  		return r;
  
  	usbi_add_pollfd(ctx, transfer_priv->pollable_fd.fd,
  		(short)(IS_XFERIN(transfer) ? POLLIN : POLLOUT));
  
  	return LIBUSB_SUCCESS;
  }
  
  static int submit_control_transfer(struct usbi_transfer *itransfer)
  {
  	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
  	struct libusb_context *ctx = DEVICE_CTX(transfer->dev_handle->dev);
  	struct windows_transfer_priv *transfer_priv = usbi_transfer_get_os_priv(itransfer);
  	struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
  	int r;
  
  	r = priv->apib->submit_control_transfer(SUB_API_NOTSET, itransfer);
  	if (r != LIBUSB_SUCCESS)
  		return r;
  
  	usbi_add_pollfd(ctx, transfer_priv->pollable_fd.fd, POLLIN);
  
  	return LIBUSB_SUCCESS;
  }
  
  static int windows_submit_transfer(struct usbi_transfer *itransfer)
  {
  	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
  
  	switch (transfer->type) {
  	case LIBUSB_TRANSFER_TYPE_CONTROL:
  		return submit_control_transfer(itransfer);
  	case LIBUSB_TRANSFER_TYPE_BULK:
  	case LIBUSB_TRANSFER_TYPE_INTERRUPT:
  		if (IS_XFEROUT(transfer) && (transfer->flags & LIBUSB_TRANSFER_ADD_ZERO_PACKET))
  			return LIBUSB_ERROR_NOT_SUPPORTED;
  		return submit_bulk_transfer(itransfer);
  	case LIBUSB_TRANSFER_TYPE_ISOCHRONOUS:
  		return submit_iso_transfer(itransfer);
  	case LIBUSB_TRANSFER_TYPE_BULK_STREAM:
  		return LIBUSB_ERROR_NOT_SUPPORTED;
  	default:
  		usbi_err(TRANSFER_CTX(transfer), "unknown endpoint type %d", transfer->type);
  		return LIBUSB_ERROR_INVALID_PARAM;
  	}
  }
  
  static int windows_abort_control(struct usbi_transfer *itransfer)
  {
  	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
  	struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
  
  	return priv->apib->abort_control(SUB_API_NOTSET, itransfer);
  }
  
  static int windows_abort_transfers(struct usbi_transfer *itransfer)
  {
  	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
  	struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
  
  	return priv->apib->abort_transfers(SUB_API_NOTSET, itransfer);
  }
  
  static int windows_cancel_transfer(struct usbi_transfer *itransfer)
  {
  	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
  
  	switch (transfer->type) {
  	case LIBUSB_TRANSFER_TYPE_CONTROL:
  		return windows_abort_control(itransfer);
  	case LIBUSB_TRANSFER_TYPE_BULK:
  	case LIBUSB_TRANSFER_TYPE_INTERRUPT:
  	case LIBUSB_TRANSFER_TYPE_ISOCHRONOUS:
  		return windows_abort_transfers(itransfer);
  	case LIBUSB_TRANSFER_TYPE_BULK_STREAM:
  		return LIBUSB_ERROR_NOT_SUPPORTED;
  	default:
  		usbi_err(ITRANSFER_CTX(itransfer), "unknown endpoint type %d", transfer->type);
  		return LIBUSB_ERROR_INVALID_PARAM;
  	}
  }
  
  int windows_copy_transfer_data(struct usbi_transfer *itransfer, uint32_t io_size)
  {
  	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
  	struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
  	return priv->apib->copy_transfer_data(SUB_API_NOTSET, itransfer, io_size);
  }
  
  struct winfd *windows_get_fd(struct usbi_transfer *transfer)
  {
  	struct windows_transfer_priv *transfer_priv = usbi_transfer_get_os_priv(transfer);
  	return &transfer_priv->pollable_fd;
  }
  
  void windows_get_overlapped_result(struct usbi_transfer *transfer, struct winfd *pollable_fd, DWORD *io_result, DWORD *io_size)
  {
  	if (HasOverlappedIoCompletedSync(pollable_fd->overlapped)) {
  		*io_result = NO_ERROR;
  		*io_size = (DWORD)pollable_fd->overlapped->InternalHigh;
  	}
  	else if (GetOverlappedResult(pollable_fd->handle, pollable_fd->overlapped, io_size, false)) {
  		// Regular async overlapped
  		*io_result = NO_ERROR;
  	}
  	else {
  		*io_result = GetLastError();
  	}
  }
  
  // NB: MSVC6 does not support named initializers.
  const struct usbi_os_backend windows_backend = {
  	"Windows",
  	USBI_CAP_HAS_HID_ACCESS,
  	windows_init,
  	windows_exit,
  
  	windows_get_device_list,
  	NULL,				/* hotplug_poll */
  	windows_open,
  	windows_close,
  
  	windows_get_device_descriptor,
  	windows_get_active_config_descriptor,
  	windows_get_config_descriptor,
  	windows_get_config_descriptor_by_value,
  
  	windows_get_configuration,
  	windows_set_configuration,
  	windows_claim_interface,
  	windows_release_interface,
  
  	windows_set_interface_altsetting,
  	windows_clear_halt,
  	windows_reset_device,
  
  	NULL,				/* alloc_streams */
  	NULL,				/* free_streams */
  
  	NULL,				/* dev_mem_alloc */
  	NULL,				/* dev_mem_free */
  
  	windows_kernel_driver_active,
  	windows_detach_kernel_driver,
  	windows_attach_kernel_driver,
  
  	windows_destroy_device,
  
  	windows_submit_transfer,
  	windows_cancel_transfer,
  	windows_clear_transfer_priv,
  
  	windows_handle_events,
  	NULL,
  
  	windows_clock_gettime,
  #if defined(USBI_TIMERFD_AVAILABLE)
  	NULL,
  #endif
  	sizeof(struct windows_device_priv),
  	sizeof(struct windows_device_handle_priv),
  	sizeof(struct windows_transfer_priv),
  };
  
  
  /*
   * USB API backends
   */
  static int unsupported_init(int sub_api, struct libusb_context *ctx)
  {
  	return LIBUSB_SUCCESS;
  }
  
  static int unsupported_exit(int sub_api)
  {
  	return LIBUSB_SUCCESS;
  }
  
  static int unsupported_open(int sub_api, struct libusb_device_handle *dev_handle)
  {
  	PRINT_UNSUPPORTED_API(open);
  }
  
  static void unsupported_close(int sub_api, struct libusb_device_handle *dev_handle)
  {
  	usbi_dbg("unsupported API call for 'close'");
  }
  
  static int unsupported_configure_endpoints(int sub_api, struct libusb_device_handle *dev_handle, int iface)
  {
  	PRINT_UNSUPPORTED_API(configure_endpoints);
  }
  
  static int unsupported_claim_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface)
  {
  	PRINT_UNSUPPORTED_API(claim_interface);
  }
  
  static int unsupported_set_interface_altsetting(int sub_api, struct libusb_device_handle *dev_handle, int iface, int altsetting)
  {
  	PRINT_UNSUPPORTED_API(set_interface_altsetting);
  }
  
  static int unsupported_release_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface)
  {
  	PRINT_UNSUPPORTED_API(release_interface);
  }
  
  static int unsupported_clear_halt(int sub_api, struct libusb_device_handle *dev_handle, unsigned char endpoint)
  {
  	PRINT_UNSUPPORTED_API(clear_halt);
  }
  
  static int unsupported_reset_device(int sub_api, struct libusb_device_handle *dev_handle)
  {
  	PRINT_UNSUPPORTED_API(reset_device);
  }
  
  static int unsupported_submit_bulk_transfer(int sub_api, struct usbi_transfer *itransfer)
  {
  	PRINT_UNSUPPORTED_API(submit_bulk_transfer);
  }
  
  static int unsupported_submit_iso_transfer(int sub_api, struct usbi_transfer *itransfer)
  {
  	PRINT_UNSUPPORTED_API(submit_iso_transfer);
  }
  
  static int unsupported_submit_control_transfer(int sub_api, struct usbi_transfer *itransfer)
  {
  	PRINT_UNSUPPORTED_API(submit_control_transfer);
  }
  
  static int unsupported_abort_control(int sub_api, struct usbi_transfer *itransfer)
  {
  	PRINT_UNSUPPORTED_API(abort_control);
  }
  
  static int unsupported_abort_transfers(int sub_api, struct usbi_transfer *itransfer)
  {
  	PRINT_UNSUPPORTED_API(abort_transfers);
  }
  
  static int unsupported_copy_transfer_data(int sub_api, struct usbi_transfer *itransfer, uint32_t io_size)
  {
  	PRINT_UNSUPPORTED_API(copy_transfer_data);
  }
  
  static int common_configure_endpoints(int sub_api, struct libusb_device_handle *dev_handle, int iface)
  {
  	return LIBUSB_SUCCESS;
  }
  
  // These names must be uppercase
  static const char *hub_driver_names[] = {"USBHUB", "USBHUB3", "USB3HUB", "NUSB3HUB", "RUSB3HUB", "FLXHCIH", "TIHUB3", "ETRONHUB3", "VIAHUB3", "ASMTHUB3", "IUSB3HUB", "VUSB3HUB", "AMDHUB30", "VHHUB", "AUSB3HUB"};
  static const char *composite_driver_names[] = {"USBCCGP"};
  static const char *winusbx_driver_names[] = WINUSBX_DRV_NAMES;
  static const char *hid_driver_names[] = {"HIDUSB", "MOUHID", "KBDHID"};
  const struct windows_usb_api_backend usb_api_backend[USB_API_MAX] = {
  	{
  		USB_API_UNSUPPORTED,
  		"Unsupported API",
  		NULL,
  		0,
  		unsupported_init,
  		unsupported_exit,
  		unsupported_open,
  		unsupported_close,
  		unsupported_configure_endpoints,
  		unsupported_claim_interface,
  		unsupported_set_interface_altsetting,
  		unsupported_release_interface,
  		unsupported_clear_halt,
  		unsupported_reset_device,
  		unsupported_submit_bulk_transfer,
  		unsupported_submit_iso_transfer,
  		unsupported_submit_control_transfer,
  		unsupported_abort_control,
  		unsupported_abort_transfers,
  		unsupported_copy_transfer_data,
  	},
  	{
  		USB_API_HUB,
  		"HUB API",
  		hub_driver_names,
  		ARRAYSIZE(hub_driver_names),
  		unsupported_init,
  		unsupported_exit,
  		unsupported_open,
  		unsupported_close,
  		unsupported_configure_endpoints,
  		unsupported_claim_interface,
  		unsupported_set_interface_altsetting,
  		unsupported_release_interface,
  		unsupported_clear_halt,
  		unsupported_reset_device,
  		unsupported_submit_bulk_transfer,
  		unsupported_submit_iso_transfer,
  		unsupported_submit_control_transfer,
  		unsupported_abort_control,
  		unsupported_abort_transfers,
  		unsupported_copy_transfer_data,
  	},
  	{
  		USB_API_COMPOSITE,
  		"Composite API",
  		composite_driver_names,
  		ARRAYSIZE(composite_driver_names),
  		composite_init,
  		composite_exit,
  		composite_open,
  		composite_close,
  		common_configure_endpoints,
  		composite_claim_interface,
  		composite_set_interface_altsetting,
  		composite_release_interface,
  		composite_clear_halt,
  		composite_reset_device,
  		composite_submit_bulk_transfer,
  		composite_submit_iso_transfer,
  		composite_submit_control_transfer,
  		composite_abort_control,
  		composite_abort_transfers,
  		composite_copy_transfer_data,
  	},
  	{
  		USB_API_WINUSBX,
  		"WinUSB-like APIs",
  		winusbx_driver_names,
  		ARRAYSIZE(winusbx_driver_names),
  		winusbx_init,
  		winusbx_exit,
  		winusbx_open,
  		winusbx_close,
  		winusbx_configure_endpoints,
  		winusbx_claim_interface,
  		winusbx_set_interface_altsetting,
  		winusbx_release_interface,
  		winusbx_clear_halt,
  		winusbx_reset_device,
  		winusbx_submit_bulk_transfer,
  		unsupported_submit_iso_transfer,
  		winusbx_submit_control_transfer,
  		winusbx_abort_control,
  		winusbx_abort_transfers,
  		winusbx_copy_transfer_data,
  	},
  	{
  		USB_API_HID,
  		"HID API",
  		hid_driver_names,
  		ARRAYSIZE(hid_driver_names),
  		hid_init,
  		hid_exit,
  		hid_open,
  		hid_close,
  		common_configure_endpoints,
  		hid_claim_interface,
  		hid_set_interface_altsetting,
  		hid_release_interface,
  		hid_clear_halt,
  		hid_reset_device,
  		hid_submit_bulk_transfer,
  		unsupported_submit_iso_transfer,
  		hid_submit_control_transfer,
  		hid_abort_transfers,
  		hid_abort_transfers,
  		hid_copy_transfer_data,
  	},
  };
  
  
  /*
   * WinUSB-like (WinUSB, libusb0/libusbK through libusbk DLL) API functions
   */
  #define WinUSBX_Set(fn)										\
  	do {											\
  		if (native_winusb)								\
  			WinUSBX[i].fn = (WinUsb_##fn##_t)GetProcAddress(h, "WinUsb_" #fn);	\
  		else										\
  			pLibK_GetProcAddress((PVOID *)&WinUSBX[i].fn, i, KUSB_FNID_##fn);	\
  	} while (0)
  
  static int winusbx_init(int sub_api, struct libusb_context *ctx)
  {
  	HMODULE h;
  	bool native_winusb;
  	int i;
  	KLIB_VERSION LibK_Version;
  	LibK_GetProcAddress_t pLibK_GetProcAddress = NULL;
  	LibK_GetVersion_t pLibK_GetVersion;
  
  	h = LoadLibraryA("libusbK");
  
  	if (h == NULL) {
  		usbi_info(ctx, "libusbK DLL is not available, will use native WinUSB");
  		h = LoadLibraryA("WinUSB");
  
  		if (h == NULL) {
  			usbi_warn(ctx, "WinUSB DLL is not available either, "
  				"you will not be able to access devices outside of enumeration");
  			return LIBUSB_ERROR_NOT_FOUND;
  		}
  	} else {
  		usbi_dbg("using libusbK DLL for universal access");
  		pLibK_GetVersion = (LibK_GetVersion_t)GetProcAddress(h, "LibK_GetVersion");
  		if (pLibK_GetVersion != NULL) {
  			pLibK_GetVersion(&LibK_Version);
  			usbi_dbg("libusbK version: %d.%d.%d.%d", LibK_Version.Major, LibK_Version.Minor,
  				LibK_Version.Micro, LibK_Version.Nano);
  		}
  		pLibK_GetProcAddress = (LibK_GetProcAddress_t)GetProcAddress(h, "LibK_GetProcAddress");
  		if (pLibK_GetProcAddress == NULL) {
  			usbi_err(ctx, "LibK_GetProcAddress() not found in libusbK DLL");
  			FreeLibrary(h);
  			return LIBUSB_ERROR_NOT_FOUND;
  		}
  	}
  
  	native_winusb = (pLibK_GetProcAddress == NULL);
  	for (i = SUB_API_LIBUSBK; i < SUB_API_MAX; i++) {
  		WinUSBX_Set(AbortPipe);
  		WinUSBX_Set(ControlTransfer);
  		WinUSBX_Set(FlushPipe);
  		WinUSBX_Set(Free);
  		WinUSBX_Set(GetAssociatedInterface);
  		WinUSBX_Set(GetCurrentAlternateSetting);
  		WinUSBX_Set(GetDescriptor);
  		WinUSBX_Set(GetOverlappedResult);
  		WinUSBX_Set(GetPipePolicy);
  		WinUSBX_Set(GetPowerPolicy);
  		WinUSBX_Set(Initialize);
  		WinUSBX_Set(QueryDeviceInformation);
  		WinUSBX_Set(QueryInterfaceSettings);
  		WinUSBX_Set(QueryPipe);
  		WinUSBX_Set(ReadPipe);
  		WinUSBX_Set(ResetPipe);
  		WinUSBX_Set(SetCurrentAlternateSetting);
  		WinUSBX_Set(SetPipePolicy);
  		WinUSBX_Set(SetPowerPolicy);
  		WinUSBX_Set(WritePipe);
  		if (!native_winusb)
  			WinUSBX_Set(ResetDevice);
  
  		if (WinUSBX[i].Initialize != NULL) {
  			WinUSBX[i].initialized = true;
  			usbi_dbg("initalized sub API %s", sub_api_name[i]);
  		} else {
  			usbi_warn(ctx, "Failed to initalize sub API %s", sub_api_name[i]);
  			WinUSBX[i].initialized = false;
  		}
  	}
  
  	WinUSBX_handle = h;
  	return LIBUSB_SUCCESS;
  }
  
  static int winusbx_exit(int sub_api)
  {
  	if (WinUSBX_handle != NULL) {
  		FreeLibrary(WinUSBX_handle);
  		WinUSBX_handle = NULL;
  
  		/* Reset the WinUSBX API structures */
  		memset(&WinUSBX, 0, sizeof(WinUSBX));
  	}
  
  	return LIBUSB_SUCCESS;
  }
  
  // NB: open and close must ensure that they only handle interface of
  // the right API type, as these functions can be called wholesale from
  // composite_open(), with interfaces belonging to different APIs
  static int winusbx_open(int sub_api, struct libusb_device_handle *dev_handle)
  {
  	struct libusb_context *ctx = DEVICE_CTX(dev_handle->dev);
  	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
  	struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
  
  	HANDLE file_handle;
  	int i;
  
  	CHECK_WINUSBX_AVAILABLE(sub_api);
  
  	// WinUSB requires a separate handle for each interface
  	for (i = 0; i < USB_MAXINTERFACES; i++) {
  		if ((priv->usb_interface[i].path != NULL)
  				&& (priv->usb_interface[i].apib->id == USB_API_WINUSBX)) {
  			file_handle = CreateFileA(priv->usb_interface[i].path, GENERIC_WRITE | GENERIC_READ, FILE_SHARE_WRITE | FILE_SHARE_READ,
  				NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED, NULL);
  			if (file_handle == INVALID_HANDLE_VALUE) {
  				usbi_err(ctx, "could not open device %s (interface %d): %s", priv->usb_interface[i].path, i, windows_error_str(0));
  				switch(GetLastError()) {
  				case ERROR_FILE_NOT_FOUND: // The device was disconnected
  					return LIBUSB_ERROR_NO_DEVICE;
  				case ERROR_ACCESS_DENIED:
  					return LIBUSB_ERROR_ACCESS;
  				default:
  					return LIBUSB_ERROR_IO;
  				}
  			}
  			handle_priv->interface_handle[i].dev_handle = file_handle;
  		}
  	}
  
  	return LIBUSB_SUCCESS;
  }
  
  static void winusbx_close(int sub_api, struct libusb_device_handle *dev_handle)
  {
  	struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
  	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
  	HANDLE handle;
  	int i;
  
  	if (sub_api == SUB_API_NOTSET)
  		sub_api = priv->sub_api;
  
  	if (!WinUSBX[sub_api].initialized)
  		return;
  
  	if (priv->apib->id == USB_API_COMPOSITE) {
  		// If this is a composite device, just free and close all WinUSB-like
  		// interfaces directly (each is independent and not associated with another)
  		for (i = 0; i < USB_MAXINTERFACES; i++) {
  			if (priv->usb_interface[i].apib->id == USB_API_WINUSBX) {
  				handle = handle_priv->interface_handle[i].api_handle;
  				if (HANDLE_VALID(handle))
  					WinUSBX[sub_api].Free(handle);
  
  				handle = handle_priv->interface_handle[i].dev_handle;
  				if (HANDLE_VALID(handle))
  					CloseHandle(handle);
  			}
  		}
  	}
  	else {
  		// If this is a WinUSB device, free all interfaces above interface 0,
  		// then free and close interface 0 last
  		for (i = 1; i < USB_MAXINTERFACES; i++) {
  			handle = handle_priv->interface_handle[i].api_handle;
  			if (HANDLE_VALID(handle))
  				WinUSBX[sub_api].Free(handle);
  		}
  		handle = handle_priv->interface_handle[0].api_handle;
  		if (HANDLE_VALID(handle))
  			WinUSBX[sub_api].Free(handle);
  
  		handle = handle_priv->interface_handle[0].dev_handle;
  		if (HANDLE_VALID(handle))
  			CloseHandle(handle);
  	}
  }
  
  static int winusbx_configure_endpoints(int sub_api, struct libusb_device_handle *dev_handle, int iface)
  {
  	struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
  	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
  	HANDLE winusb_handle = handle_priv->interface_handle[iface].api_handle;
  	UCHAR policy;
  	ULONG timeout = 0;
  	uint8_t endpoint_address;
  	int i;
  
  	CHECK_WINUSBX_AVAILABLE(sub_api);
  
  	// With handle and enpoints set (in parent), we can setup the default pipe properties
  	// see http://download.microsoft.com/download/D/1/D/D1DD7745-426B-4CC3-A269-ABBBE427C0EF/DVC-T705_DDC08.pptx
  	for (i = -1; i < priv->usb_interface[iface].nb_endpoints; i++) {
  		endpoint_address = (i == -1) ? 0 : priv->usb_interface[iface].endpoint[i];
  		if (!WinUSBX[sub_api].SetPipePolicy(winusb_handle, endpoint_address,
  			PIPE_TRANSFER_TIMEOUT, sizeof(ULONG), &timeout))
  			usbi_dbg("failed to set PIPE_TRANSFER_TIMEOUT for control endpoint %02X", endpoint_address);
  
  		if ((i == -1) || (sub_api == SUB_API_LIBUSB0))
  			continue; // Other policies don't apply to control endpoint or libusb0
  
  		policy = false;
  		if (!WinUSBX[sub_api].SetPipePolicy(winusb_handle, endpoint_address,
  			SHORT_PACKET_TERMINATE, sizeof(UCHAR), &policy))
  			usbi_dbg("failed to disable SHORT_PACKET_TERMINATE for endpoint %02X", endpoint_address);
  
  		if (!WinUSBX[sub_api].SetPipePolicy(winusb_handle, endpoint_address,
  			IGNORE_SHORT_PACKETS, sizeof(UCHAR), &policy))
  			usbi_dbg("failed to disable IGNORE_SHORT_PACKETS for endpoint %02X", endpoint_address);
  
  		policy = true;
  		/* ALLOW_PARTIAL_READS must be enabled due to likely libusbK bug. See:
  		   https://sourceforge.net/mailarchive/message.php?msg_id=29736015 */
  		if (!WinUSBX[sub_api].SetPipePolicy(winusb_handle, endpoint_address,
  			ALLOW_PARTIAL_READS, sizeof(UCHAR), &policy))
  			usbi_dbg("failed to enable ALLOW_PARTIAL_READS for endpoint %02X", endpoint_address);
  
  		if (!WinUSBX[sub_api].SetPipePolicy(winusb_handle, endpoint_address,
  			AUTO_CLEAR_STALL, sizeof(UCHAR), &policy))
  			usbi_dbg("failed to enable AUTO_CLEAR_STALL for endpoint %02X", endpoint_address);
  	}
  
  	return LIBUSB_SUCCESS;
  }
  
  static int winusbx_claim_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface)
  {
  	struct libusb_context *ctx = DEVICE_CTX(dev_handle->dev);
  	struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
  	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
  	bool is_using_usbccgp = (priv->apib->id == USB_API_COMPOSITE);
  	SP_DEVICE_INTERFACE_DETAIL_DATA_A *dev_interface_details = NULL;
  	HDEVINFO dev_info = INVALID_HANDLE_VALUE;
  	SP_DEVINFO_DATA dev_info_data;
  	char *dev_path_no_guid = NULL;
  	char filter_path[] = "\\\\.\\libusb0-0000";
  	bool found_filter = false;
  	HANDLE file_handle, winusb_handle;
  	DWORD err;
  	int i;
  
  	CHECK_WINUSBX_AVAILABLE(sub_api);
  
  	// If the device is composite, but using the default Windows composite parent driver (usbccgp)
  	// or if it's the first WinUSB-like interface, we get a handle through Initialize().
  	if ((is_using_usbccgp) || (iface == 0)) {
  		// composite device (independent interfaces) or interface 0
  		file_handle = handle_priv->interface_handle[iface].dev_handle;
  		if (!HANDLE_VALID(file_handle))
  			return LIBUSB_ERROR_NOT_FOUND;
  
  		if (!WinUSBX[sub_api].Initialize(file_handle, &winusb_handle)) {
  			handle_priv->interface_handle[iface].api_handle = INVALID_HANDLE_VALUE;
  			err = GetLastError();
  			switch(err) {
  			case ERROR_BAD_COMMAND:
  				// The device was disconnected
  				usbi_err(ctx, "could not access interface %d: %s", iface, windows_error_str(0));
  				return LIBUSB_ERROR_NO_DEVICE;
  			default:
  				// it may be that we're using the libusb0 filter driver.
  				// TODO: can we move this whole business into the K/0 DLL?
  				for (i = 0; ; i++) {
  					safe_free(dev_interface_details);
  					safe_free(dev_path_no_guid);
  					dev_interface_details = get_interface_details_filter(ctx, &dev_info, &dev_info_data, &GUID_DEVINTERFACE_LIBUSB0_FILTER, i, filter_path);
  					if ((found_filter) || (dev_interface_details == NULL))
  						break;
  
  					// ignore GUID part
  					dev_path_no_guid = sanitize_path(strtok(dev_interface_details->DevicePath, "{"));
  					if (safe_strncmp(dev_path_no_guid, priv->usb_interface[iface].path, safe_strlen(dev_path_no_guid)) == 0) {
  						file_handle = CreateFileA(filter_path, GENERIC_WRITE | GENERIC_READ, FILE_SHARE_WRITE | FILE_SHARE_READ,
  							NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED, NULL);
  						if (file_handle == INVALID_HANDLE_VALUE) {
  							usbi_err(ctx, "could not open device %s: %s", filter_path, windows_error_str(0));
  						} else {
  							WinUSBX[sub_api].Free(winusb_handle);
  							if (WinUSBX[sub_api].Initialize(file_handle, &winusb_handle))
  								found_filter = true;
  							else
  								usbi_err(ctx, "could not initialize filter driver for %s", filter_path);
  						}
  					}
  				}
  				if (!found_filter) {
  					usbi_err(ctx, "could not access interface %d: %s", iface, windows_error_str(err));
  					return LIBUSB_ERROR_ACCESS;
  				}
  			}
  		}
  		handle_priv->interface_handle[iface].api_handle = winusb_handle;
  	} else {
  		// For all other interfaces, use GetAssociatedInterface()
  		winusb_handle = handle_priv->interface_handle[0].api_handle;
  		// It is a requirement for multiple interface devices on Windows that, to you
  		// must first claim the first interface before you claim the others
  		if (!HANDLE_VALID(winusb_handle)) {
  			file_handle = handle_priv->interface_handle[0].dev_handle;
  			if (WinUSBX[sub_api].Initialize(file_handle, &winusb_handle)) {
  				handle_priv->interface_handle[0].api_handle = winusb_handle;
  				usbi_warn(ctx, "auto-claimed interface 0 (required to claim %d with WinUSB)", iface);
  			} else {
  				usbi_warn(ctx, "failed to auto-claim interface 0 (required to claim %d with WinUSB): %s", iface, windows_error_str(0));
  				return LIBUSB_ERROR_ACCESS;
  			}
  		}
  		if (!WinUSBX[sub_api].GetAssociatedInterface(winusb_handle, (UCHAR)(iface - 1),
  			&handle_priv->interface_handle[iface].api_handle)) {
  			handle_priv->interface_handle[iface].api_handle = INVALID_HANDLE_VALUE;
  			switch(GetLastError()) {
  			case ERROR_NO_MORE_ITEMS:   // invalid iface
  				return LIBUSB_ERROR_NOT_FOUND;
  			case ERROR_BAD_COMMAND:     // The device was disconnected
  				return LIBUSB_ERROR_NO_DEVICE;
  			case ERROR_ALREADY_EXISTS:  // already claimed
  				return LIBUSB_ERROR_BUSY;
  			default:
  				usbi_err(ctx, "could not claim interface %d: %s", iface, windows_error_str(0));
  				return LIBUSB_ERROR_ACCESS;
  			}
  		}
  	}
  	usbi_dbg("claimed interface %d", iface);
  	handle_priv->active_interface = iface;
  
  	return LIBUSB_SUCCESS;
  }
  
  static int winusbx_release_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface)
  {
  	struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
  	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
  	HANDLE winusb_handle;
  
  	CHECK_WINUSBX_AVAILABLE(sub_api);
  
  	winusb_handle = handle_priv->interface_handle[iface].api_handle;
  	if (!HANDLE_VALID(winusb_handle))
  		return LIBUSB_ERROR_NOT_FOUND;
  
  	WinUSBX[sub_api].Free(winusb_handle);
  	handle_priv->interface_handle[iface].api_handle = INVALID_HANDLE_VALUE;
  
  	return LIBUSB_SUCCESS;
  }
  
  /*
   * Return the first valid interface (of the same API type), for control transfers
   */
  static int get_valid_interface(struct libusb_device_handle *dev_handle, int api_id)
  {
  	struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
  	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
  	int i;
  
  	if ((api_id < USB_API_WINUSBX) || (api_id > USB_API_HID)) {
  		usbi_dbg("unsupported API ID");
  		return -1;
  	}
  
  	for (i = 0; i < USB_MAXINTERFACES; i++) {
  		if (HANDLE_VALID(handle_priv->interface_handle[i].dev_handle)
  				&& HANDLE_VALID(handle_priv->interface_handle[i].api_handle)
  				&& (priv->usb_interface[i].apib->id == api_id))
  			return i;
  	}
  
  	return -1;
  }
  
  /*
   * Lookup interface by endpoint address. -1 if not found
   */
  static int interface_by_endpoint(struct windows_device_priv *priv,
  	struct windows_device_handle_priv *handle_priv, uint8_t endpoint_address)
  {
  	int i, j;
  
  	for (i = 0; i < USB_MAXINTERFACES; i++) {
  		if (!HANDLE_VALID(handle_priv->interface_handle[i].api_handle))
  			continue;
  		if (priv->usb_interface[i].endpoint == NULL)
  			continue;
  		for (j = 0; j < priv->usb_interface[i].nb_endpoints; j++) {
  			if (priv->usb_interface[i].endpoint[j] == endpoint_address)
  				return i;
  		}
  	}
  
  	return -1;
  }
  
  static int winusbx_submit_control_transfer(int sub_api, struct usbi_transfer *itransfer)
  {
  	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
  	struct libusb_context *ctx = DEVICE_CTX(transfer->dev_handle->dev);
  	struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
  	struct windows_transfer_priv *transfer_priv = usbi_transfer_get_os_priv(itransfer);
  	struct windows_device_handle_priv *handle_priv = _device_handle_priv(transfer->dev_handle);
  	WINUSB_SETUP_PACKET *setup = (WINUSB_SETUP_PACKET *)transfer->buffer;
  	ULONG size;
  	HANDLE winusb_handle;
  	int current_interface;
  	struct winfd wfd;
  
  	CHECK_WINUSBX_AVAILABLE(sub_api);
  
  	transfer_priv->pollable_fd = INVALID_WINFD;
  	size = transfer->length - LIBUSB_CONTROL_SETUP_SIZE;
  
  	// Windows places upper limits on the control transfer size
  	// See: https://msdn.microsoft.com/en-us/library/windows/hardware/ff538112.aspx
  	if (size > MAX_CTRL_BUFFER_LENGTH)
  		return LIBUSB_ERROR_INVALID_PARAM;
  
  	current_interface = get_valid_interface(transfer->dev_handle, USB_API_WINUSBX);
  	if (current_interface < 0) {
  		if (auto_claim(transfer, &current_interface, USB_API_WINUSBX) != LIBUSB_SUCCESS)
  			return LIBUSB_ERROR_NOT_FOUND;
  	}
  
  	usbi_dbg("will use interface %d", current_interface);
  	winusb_handle = handle_priv->interface_handle[current_interface].api_handle;
  
  	wfd = usbi_create_fd(winusb_handle, RW_READ, NULL, NULL);
  	// Always use the handle returned from usbi_create_fd (wfd.handle)
  	if (wfd.fd < 0)
  		return LIBUSB_ERROR_NO_MEM;
  
  	// Sending of set configuration control requests from WinUSB creates issues
  	if (((setup->request_type & (0x03 << 5)) == LIBUSB_REQUEST_TYPE_STANDARD)
  			&& (setup->request == LIBUSB_REQUEST_SET_CONFIGURATION)) {
  		if (setup->value != priv->active_config) {
  			usbi_warn(ctx, "cannot set configuration other than the default one");
  			usbi_free_fd(&wfd);
  			return LIBUSB_ERROR_INVALID_PARAM;
  		}
  		wfd.overlapped->Internal = STATUS_COMPLETED_SYNCHRONOUSLY;
  		wfd.overlapped->InternalHigh = 0;
  	} else {
  		if (!WinUSBX[sub_api].ControlTransfer(wfd.handle, *setup, transfer->buffer + LIBUSB_CONTROL_SETUP_SIZE, size, NULL, wfd.overlapped)) {
  			if (GetLastError() != ERROR_IO_PENDING) {
  				usbi_warn(ctx, "ControlTransfer failed: %s", windows_error_str(0));
  				usbi_free_fd(&wfd);
  				return LIBUSB_ERROR_IO;
  			}
  		} else {
  			wfd.overlapped->Internal = STATUS_COMPLETED_SYNCHRONOUSLY;
  			wfd.overlapped->InternalHigh = (DWORD)size;
  		}
  	}
  
  	// Use priv_transfer to store data needed for async polling
  	transfer_priv->pollable_fd = wfd;
  	transfer_priv->interface_number = (uint8_t)current_interface;
  
  	return LIBUSB_SUCCESS;
  }
  
  static int winusbx_set_interface_altsetting(int sub_api, struct libusb_device_handle *dev_handle, int iface, int altsetting)
  {
  	struct libusb_context *ctx = DEVICE_CTX(dev_handle->dev);
  	struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
  	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
  	HANDLE winusb_handle;
  
  	CHECK_WINUSBX_AVAILABLE(sub_api);
  
  	if (altsetting > 255)
  		return LIBUSB_ERROR_INVALID_PARAM;
  
  	winusb_handle = handle_priv->interface_handle[iface].api_handle;
  	if (!HANDLE_VALID(winusb_handle)) {
  		usbi_err(ctx, "interface must be claimed first");
  		return LIBUSB_ERROR_NOT_FOUND;
  	}
  
  	if (!WinUSBX[sub_api].SetCurrentAlternateSetting(winusb_handle, (UCHAR)altsetting)) {
  		usbi_err(ctx, "SetCurrentAlternateSetting failed: %s", windows_error_str(0));
  		return LIBUSB_ERROR_IO;
  	}
  
  	return LIBUSB_SUCCESS;
  }
  
  static int winusbx_submit_bulk_transfer(int sub_api, struct usbi_transfer *itransfer)
  {
  	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
  	struct libusb_context *ctx = DEVICE_CTX(transfer->dev_handle->dev);
  	struct windows_transfer_priv *transfer_priv = usbi_transfer_get_os_priv(itransfer);
  	struct windows_device_handle_priv *handle_priv = _device_handle_priv(transfer->dev_handle);
  	struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
  	HANDLE winusb_handle;
  	bool ret;
  	int current_interface;
  	struct winfd wfd;
  
  	CHECK_WINUSBX_AVAILABLE(sub_api);
  
  	transfer_priv->pollable_fd = INVALID_WINFD;
  
  	current_interface = interface_by_endpoint(priv, handle_priv, transfer->endpoint);
  	if (current_interface < 0) {
  		usbi_err(ctx, "unable to match endpoint to an open interface - cancelling transfer");
  		return LIBUSB_ERROR_NOT_FOUND;
  	}
  
  	usbi_dbg("matched endpoint %02X with interface %d", transfer->endpoint, current_interface);
  
  	winusb_handle = handle_priv->interface_handle[current_interface].api_handle;
  
  	wfd = usbi_create_fd(winusb_handle, IS_XFERIN(transfer) ? RW_READ : RW_WRITE, NULL, NULL);
  	// Always use the handle returned from usbi_create_fd (wfd.handle)
  	if (wfd.fd < 0)
  		return LIBUSB_ERROR_NO_MEM;
  
  	if (IS_XFERIN(transfer)) {
  		usbi_dbg("reading %d bytes", transfer->length);
  		ret = WinUSBX[sub_api].ReadPipe(wfd.handle, transfer->endpoint, transfer->buffer, transfer->length, NULL, wfd.overlapped);
  	} else {
  		usbi_dbg("writing %d bytes", transfer->length);
  		ret = WinUSBX[sub_api].WritePipe(wfd.handle, transfer->endpoint, transfer->buffer, transfer->length, NULL, wfd.overlapped);
  	}
  
  	if (!ret) {
  		if (GetLastError() != ERROR_IO_PENDING) {
  			usbi_err(ctx, "ReadPipe/WritePipe failed: %s", windows_error_str(0));
  			usbi_free_fd(&wfd);
  			return LIBUSB_ERROR_IO;
  		}
  	} else {
  		wfd.overlapped->Internal = STATUS_COMPLETED_SYNCHRONOUSLY;
  		wfd.overlapped->InternalHigh = (DWORD)transfer->length;
  	}
  
  	transfer_priv->pollable_fd = wfd;
  	transfer_priv->interface_number = (uint8_t)current_interface;
  
  	return LIBUSB_SUCCESS;
  }
  
  static int winusbx_clear_halt(int sub_api, struct libusb_device_handle *dev_handle, unsigned char endpoint)
  {
  	struct libusb_context *ctx = DEVICE_CTX(dev_handle->dev);
  	struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
  	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
  	HANDLE winusb_handle;
  	int current_interface;
  
  	CHECK_WINUSBX_AVAILABLE(sub_api);
  
  	current_interface = interface_by_endpoint(priv, handle_priv, endpoint);
  	if (current_interface < 0) {
  		usbi_err(ctx, "unable to match endpoint to an open interface - cannot clear");
  		return LIBUSB_ERROR_NOT_FOUND;
  	}
  
  	usbi_dbg("matched endpoint %02X with interface %d", endpoint, current_interface);
  	winusb_handle = handle_priv->interface_handle[current_interface].api_handle;
  
  	if (!WinUSBX[sub_api].ResetPipe(winusb_handle, endpoint)) {
  		usbi_err(ctx, "ResetPipe failed: %s", windows_error_str(0));
  		return LIBUSB_ERROR_NO_DEVICE;
  	}
  
  	return LIBUSB_SUCCESS;
  }
  
  /*
   * from http://www.winvistatips.com/winusb-bugchecks-t335323.html (confirmed
   * through testing as well):
   * "You can not call WinUsb_AbortPipe on control pipe. You can possibly cancel
   * the control transfer using CancelIo"
   */
  static int winusbx_abort_control(int sub_api, struct usbi_transfer *itransfer)
  {
  	// Cancelling of the I/O is done in the parent
  	return LIBUSB_SUCCESS;
  }
  
  static int winusbx_abort_transfers(int sub_api, struct usbi_transfer *itransfer)
  {
  	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
  	struct libusb_context *ctx = DEVICE_CTX(transfer->dev_handle->dev);
  	struct windows_device_handle_priv *handle_priv = _device_handle_priv(transfer->dev_handle);
  	struct windows_transfer_priv *transfer_priv = usbi_transfer_get_os_priv(itransfer);
  	struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
  	HANDLE winusb_handle;
  	int current_interface;
  
  	CHECK_WINUSBX_AVAILABLE(sub_api);
  
  	current_interface = transfer_priv->interface_number;
  	if ((current_interface < 0) || (current_interface >= USB_MAXINTERFACES)) {
  		usbi_err(ctx, "program assertion failed: invalid interface_number");
  		return LIBUSB_ERROR_NOT_FOUND;
  	}
  	usbi_dbg("will use interface %d", current_interface);
  
  	winusb_handle = handle_priv->interface_handle[current_interface].api_handle;
  
  	if (!WinUSBX[sub_api].AbortPipe(winusb_handle, transfer->endpoint)) {
  		usbi_err(ctx, "AbortPipe failed: %s", windows_error_str(0));
  		return LIBUSB_ERROR_NO_DEVICE;
  	}
  
  	return LIBUSB_SUCCESS;
  }
  
  /*
   * from the "How to Use WinUSB to Communicate with a USB Device" Microsoft white paper
   * (http://www.microsoft.com/whdc/connect/usb/winusb_howto.mspx):
   * "WinUSB does not support host-initiated reset port and cycle port operations" and
   * IOCTL_INTERNAL_USB_CYCLE_PORT is only available in kernel mode and the
   * IOCTL_USB_HUB_CYCLE_PORT ioctl was removed from Vista => the best we can do is
   * cycle the pipes (and even then, the control pipe can not be reset using WinUSB)
   */
  // TODO: (post hotplug): see if we can force eject the device and redetect it (reuse hotplug?)
  static int winusbx_reset_device(int sub_api, struct libusb_device_handle *dev_handle)
  {
  	struct libusb_context *ctx = DEVICE_CTX(dev_handle->dev);
  	struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
  	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
  	struct winfd wfd;
  	HANDLE winusb_handle;
  	int i, j;
  
  	CHECK_WINUSBX_AVAILABLE(sub_api);
  
  	// Reset any available pipe (except control)
  	for (i = 0; i < USB_MAXINTERFACES; i++) {
  		winusb_handle = handle_priv->interface_handle[i].api_handle;
  		for (wfd = handle_to_winfd(winusb_handle); wfd.fd > 0; ) {
  			// Cancel any pollable I/O
  			usbi_remove_pollfd(ctx, wfd.fd);
  			usbi_free_fd(&wfd);
  			wfd = handle_to_winfd(winusb_handle);
  		}
  
  		if (HANDLE_VALID(winusb_handle)) {
  			for (j = 0; j < priv->usb_interface[i].nb_endpoints; j++) {
  				usbi_dbg("resetting ep %02X", priv->usb_interface[i].endpoint[j]);
  				if (!WinUSBX[sub_api].AbortPipe(winusb_handle, priv->usb_interface[i].endpoint[j]))
  					usbi_err(ctx, "AbortPipe (pipe address %02X) failed: %s",
  						priv->usb_interface[i].endpoint[j], windows_error_str(0));
  
  				// FlushPipe seems to fail on OUT pipes
  				if (IS_EPIN(priv->usb_interface[i].endpoint[j])
  						&& (!WinUSBX[sub_api].FlushPipe(winusb_handle, priv->usb_interface[i].endpoint[j])))
  					usbi_err(ctx, "FlushPipe (pipe address %02X) failed: %s",
  						priv->usb_interface[i].endpoint[j], windows_error_str(0));
  
  				if (!WinUSBX[sub_api].ResetPipe(winusb_handle, priv->usb_interface[i].endpoint[j]))
  					usbi_err(ctx, "ResetPipe (pipe address %02X) failed: %s",
  						priv->usb_interface[i].endpoint[j], windows_error_str(0));
  			}
  		}
  	}
  
  	// libusbK & libusb0 have the ability to issue an actual device reset
  	if (WinUSBX[sub_api].ResetDevice != NULL) {
  		winusb_handle = handle_priv->interface_handle[0].api_handle;
  		if (HANDLE_VALID(winusb_handle))
  			WinUSBX[sub_api].ResetDevice(winusb_handle);
  	}
  
  	return LIBUSB_SUCCESS;
  }
  
  static int winusbx_copy_transfer_data(int sub_api, struct usbi_transfer *itransfer, uint32_t io_size)
  {
  	itransfer->transferred += io_size;
  	return LIBUSB_TRANSFER_COMPLETED;
  }
  
  /*
   * Internal HID Support functions (from libusb-win32)
   * Note that functions that complete data transfer synchronously must return
   * LIBUSB_COMPLETED instead of LIBUSB_SUCCESS
   */
  static int _hid_get_hid_descriptor(struct hid_device_priv *dev, void *data, size_t *size);
  static int _hid_get_report_descriptor(struct hid_device_priv *dev, void *data, size_t *size);
  
  static int _hid_wcslen(WCHAR *str)
  {
  	int i = 0;
  
  	while (str[i] && (str[i] != 0x409))
  		i++;
  
  	return i;
  }
  
  static int _hid_get_device_descriptor(struct hid_device_priv *dev, void *data, size_t *size)
  {
  	struct libusb_device_descriptor d;
  
  	d.bLength = LIBUSB_DT_DEVICE_SIZE;
  	d.bDescriptorType = LIBUSB_DT_DEVICE;
  	d.bcdUSB = 0x0200; /* 2.00 */
  	d.bDeviceClass = 0;
  	d.bDeviceSubClass = 0;
  	d.bDeviceProtocol = 0;
  	d.bMaxPacketSize0 = 64; /* fix this! */
  	d.idVendor = (uint16_t)dev->vid;
  	d.idProduct = (uint16_t)dev->pid;
  	d.bcdDevice = 0x0100;
  	d.iManufacturer = dev->string_index[0];
  	d.iProduct = dev->string_index[1];
  	d.iSerialNumber = dev->string_index[2];
  	d.bNumConfigurations = 1;
  
  	if (*size > LIBUSB_DT_DEVICE_SIZE)
  		*size = LIBUSB_DT_DEVICE_SIZE;
  	memcpy(data, &d, *size);
  
  	return LIBUSB_COMPLETED;
  }
  
  static int _hid_get_config_descriptor(struct hid_device_priv *dev, void *data, size_t *size)
  {
  	char num_endpoints = 0;
  	size_t config_total_len = 0;
  	char tmp[HID_MAX_CONFIG_DESC_SIZE];
  	struct libusb_config_descriptor *cd;
  	struct libusb_interface_descriptor *id;
  	struct libusb_hid_descriptor *hd;
  	struct libusb_endpoint_descriptor *ed;
  	size_t tmp_size;
  
  	if (dev->input_report_size)
  		num_endpoints++;
  	if (dev->output_report_size)
  		num_endpoints++;
  
  	config_total_len = LIBUSB_DT_CONFIG_SIZE + LIBUSB_DT_INTERFACE_SIZE
  		+ LIBUSB_DT_HID_SIZE + num_endpoints * LIBUSB_DT_ENDPOINT_SIZE;
  
  	cd = (struct libusb_config_descriptor *)tmp;
  	id = (struct libusb_interface_descriptor *)(tmp + LIBUSB_DT_CONFIG_SIZE);
  	hd = (struct libusb_hid_descriptor *)(tmp + LIBUSB_DT_CONFIG_SIZE
  		+ LIBUSB_DT_INTERFACE_SIZE);
  	ed = (struct libusb_endpoint_descriptor *)(tmp + LIBUSB_DT_CONFIG_SIZE
  		+ LIBUSB_DT_INTERFACE_SIZE
  		+ LIBUSB_DT_HID_SIZE);
  
  	cd->bLength = LIBUSB_DT_CONFIG_SIZE;
  	cd->bDescriptorType = LIBUSB_DT_CONFIG;
  	cd->wTotalLength = (uint16_t)config_total_len;
  	cd->bNumInterfaces = 1;
  	cd->bConfigurationValue = 1;
  	cd->iConfiguration = 0;
  	cd->bmAttributes = 1 << 7; /* bus powered */
  	cd->MaxPower = 50;
  
  	id->bLength = LIBUSB_DT_INTERFACE_SIZE;
  	id->bDescriptorType = LIBUSB_DT_INTERFACE;
  	id->bInterfaceNumber = 0;
  	id->bAlternateSetting = 0;
  	id->bNumEndpoints = num_endpoints;
  	id->bInterfaceClass = 3;
  	id->bInterfaceSubClass = 0;
  	id->bInterfaceProtocol = 0;
  	id->iInterface = 0;
  
  	tmp_size = LIBUSB_DT_HID_SIZE;
  	_hid_get_hid_descriptor(dev, hd, &tmp_size);
  
  	if (dev->input_report_size) {
  		ed->bLength = LIBUSB_DT_ENDPOINT_SIZE;
  		ed->bDescriptorType = LIBUSB_DT_ENDPOINT;
  		ed->bEndpointAddress = HID_IN_EP;
  		ed->bmAttributes = 3;
  		ed->wMaxPacketSize = dev->input_report_size - 1;
  		ed->bInterval = 10;
  		ed = (struct libusb_endpoint_descriptor *)((char *)ed + LIBUSB_DT_ENDPOINT_SIZE);
  	}
  
  	if (dev->output_report_size) {
  		ed->bLength = LIBUSB_DT_ENDPOINT_SIZE;
  		ed->bDescriptorType = LIBUSB_DT_ENDPOINT;
  		ed->bEndpointAddress = HID_OUT_EP;
  		ed->bmAttributes = 3;
  		ed->wMaxPacketSize = dev->output_report_size - 1;
  		ed->bInterval = 10;
  	}
  
  	if (*size > config_total_len)
  		*size = config_total_len;
  	memcpy(data, tmp, *size);
  
  	return LIBUSB_COMPLETED;
  }
  
  static int _hid_get_string_descriptor(struct hid_device_priv *dev, int _index,
  	void *data, size_t *size)
  {
  	void *tmp = NULL;
  	size_t tmp_size = 0;
  	int i;
  
  	/* language ID, EN-US */
  	char string_langid[] = {0x09, 0x04};
  
  	if ((*size < 2) || (*size > 255))
  		return LIBUSB_ERROR_OVERFLOW;
  
  	if (_index == 0) {
  		tmp = string_langid;
  		tmp_size = sizeof(string_langid) + 2;
  	} else {
  		for (i = 0; i < 3; i++) {
  			if (_index == (dev->string_index[i])) {
  				tmp = dev->string[i];
  				tmp_size = (_hid_wcslen(dev->string[i]) + 1) * sizeof(WCHAR);
  				break;
  			}
  		}
  
  		if (i == 3) // not found
  			return LIBUSB_ERROR_INVALID_PARAM;
  	}
  
  	if (!tmp_size)
  		return LIBUSB_ERROR_INVALID_PARAM;
  
  	if (tmp_size < *size)
  		*size = tmp_size;
  
  	// 2 byte header
  	((uint8_t *)data)[0] = (uint8_t)*size;
  	((uint8_t *)data)[1] = LIBUSB_DT_STRING;
  	memcpy((uint8_t *)data + 2, tmp, *size - 2);
  
  	return LIBUSB_COMPLETED;
  }
  
  static int _hid_get_hid_descriptor(struct hid_device_priv *dev, void *data, size_t *size)
  {
  	struct libusb_hid_descriptor d;
  	uint8_t tmp[MAX_HID_DESCRIPTOR_SIZE];
  	size_t report_len = MAX_HID_DESCRIPTOR_SIZE;
  
  	_hid_get_report_descriptor(dev, tmp, &report_len);
  
  	d.bLength = LIBUSB_DT_HID_SIZE;
  	d.bDescriptorType = LIBUSB_DT_HID;
  	d.bcdHID = 0x0110; /* 1.10 */
  	d.bCountryCode = 0;
  	d.bNumDescriptors = 1;
  	d.bClassDescriptorType = LIBUSB_DT_REPORT;
  	d.wClassDescriptorLength = (uint16_t)report_len;
  
  	if (*size > LIBUSB_DT_HID_SIZE)
  		*size = LIBUSB_DT_HID_SIZE;
  	memcpy(data, &d, *size);
  
  	return LIBUSB_COMPLETED;
  }
  
  static int _hid_get_report_descriptor(struct hid_device_priv *dev, void *data, size_t *size)
  {
  	uint8_t d[MAX_HID_DESCRIPTOR_SIZE];
  	size_t i = 0;
  
  	/* usage page (0xFFA0 == vendor defined) */
  	d[i++] = 0x06; d[i++] = 0xA0; d[i++] = 0xFF;
  	/* usage (vendor defined) */
  	d[i++] = 0x09; d[i++] = 0x01;
  	/* start collection (application) */
  	d[i++] = 0xA1; d[i++] = 0x01;
  	/* input report */
  	if (dev->input_report_size) {
  		/* usage (vendor defined) */
  		d[i++] = 0x09; d[i++] = 0x01;
  		/* logical minimum (0) */
  		d[i++] = 0x15; d[i++] = 0x00;
  		/* logical maximum (255) */
  		d[i++] = 0x25; d[i++] = 0xFF;
  		/* report size (8 bits) */
  		d[i++] = 0x75; d[i++] = 0x08;
  		/* report count */
  		d[i++] = 0x95; d[i++] = (uint8_t)dev->input_report_size - 1;
  		/* input (data, variable, absolute) */
  		d[i++] = 0x81; d[i++] = 0x00;
  	}
  	/* output report */
  	if (dev->output_report_size) {
  		/* usage (vendor defined) */
  		d[i++] = 0x09; d[i++] = 0x02;
  		/* logical minimum (0) */
  		d[i++] = 0x15; d[i++] = 0x00;
  		/* logical maximum (255) */
  		d[i++] = 0x25; d[i++] = 0xFF;
  		/* report size (8 bits) */
  		d[i++] = 0x75; d[i++] = 0x08;
  		/* report count */
  		d[i++] = 0x95; d[i++] = (uint8_t)dev->output_report_size - 1;
  		/* output (data, variable, absolute) */
  		d[i++] = 0x91; d[i++] = 0x00;
  	}
  	/* feature report */
  	if (dev->feature_report_size) {
  		/* usage (vendor defined) */
  		d[i++] = 0x09; d[i++] = 0x03;
  		/* logical minimum (0) */
  		d[i++] = 0x15; d[i++] = 0x00;
  		/* logical maximum (255) */
  		d[i++] = 0x25; d[i++] = 0xFF;
  		/* report size (8 bits) */
  		d[i++] = 0x75; d[i++] = 0x08;
  		/* report count */
  		d[i++] = 0x95; d[i++] = (uint8_t)dev->feature_report_size - 1;
  		/* feature (data, variable, absolute) */
  		d[i++] = 0xb2; d[i++] = 0x02; d[i++] = 0x01;
  	}
  
  	/* end collection */
  	d[i++] = 0xC0;
  
  	if (*size > i)
  		*size = i;
  	memcpy(data, d, *size);
  
  	return LIBUSB_COMPLETED;
  }
  
  static int _hid_get_descriptor(struct hid_device_priv *dev, HANDLE hid_handle, int recipient,
  	int type, int _index, void *data, size_t *size)
  {
  	switch(type) {
  	case LIBUSB_DT_DEVICE:
  		usbi_dbg("LIBUSB_DT_DEVICE");
  		return _hid_get_device_descriptor(dev, data, size);
  	case LIBUSB_DT_CONFIG:
  		usbi_dbg("LIBUSB_DT_CONFIG");
  		if (!_index)
  			return _hid_get_config_descriptor(dev, data, size);
  		return LIBUSB_ERROR_INVALID_PARAM;
  	case LIBUSB_DT_STRING:
  		usbi_dbg("LIBUSB_DT_STRING");
  		return _hid_get_string_descriptor(dev, _index, data, size);
  	case LIBUSB_DT_HID:
  		usbi_dbg("LIBUSB_DT_HID");
  		if (!_index)
  			return _hid_get_hid_descriptor(dev, data, size);
  		return LIBUSB_ERROR_INVALID_PARAM;
  	case LIBUSB_DT_REPORT:
  		usbi_dbg("LIBUSB_DT_REPORT");
  		if (!_index)
  			return _hid_get_report_descriptor(dev, data, size);
  		return LIBUSB_ERROR_INVALID_PARAM;
  	case LIBUSB_DT_PHYSICAL:
  		usbi_dbg("LIBUSB_DT_PHYSICAL");
  		if (HidD_GetPhysicalDescriptor(hid_handle, data, (ULONG)*size))
  			return LIBUSB_COMPLETED;
  		return LIBUSB_ERROR_OTHER;
  	}
  
  	usbi_dbg("unsupported");
  	return LIBUSB_ERROR_NOT_SUPPORTED;
  }
  
  static int _hid_get_report(struct hid_device_priv *dev, HANDLE hid_handle, int id, void *data,
  	struct windows_transfer_priv *tp, size_t *size, OVERLAPPED *overlapped, int report_type)
  {
  	uint8_t *buf;
  	DWORD ioctl_code, read_size, expected_size = (DWORD)*size;
  	int r = LIBUSB_SUCCESS;
  
  	if (tp->hid_buffer != NULL)
  		usbi_dbg("program assertion failed: hid_buffer is not NULL");
  
  	if ((*size == 0) || (*size > MAX_HID_REPORT_SIZE)) {
  		usbi_dbg("invalid size (%u)", *size);
  		return LIBUSB_ERROR_INVALID_PARAM;
  	}
  
  	switch (report_type) {
  	case HID_REPORT_TYPE_INPUT:
  		ioctl_code = IOCTL_HID_GET_INPUT_REPORT;
  		break;
  	case HID_REPORT_TYPE_FEATURE:
  		ioctl_code = IOCTL_HID_GET_FEATURE;
  		break;
  	default:
  		usbi_dbg("unknown HID report type %d", report_type);
  		return LIBUSB_ERROR_INVALID_PARAM;
  	}
  
  	// Add a trailing byte to detect overflows
  	buf = calloc(1, expected_size + 1);
  	if (buf == NULL)
  		return LIBUSB_ERROR_NO_MEM;
  
  	buf[0] = (uint8_t)id; // Must be set always
  	usbi_dbg("report ID: 0x%02X", buf[0]);
  
  	tp->hid_expected_size = expected_size;
  	read_size = expected_size;
  
  	// NB: The size returned by DeviceIoControl doesn't include report IDs when not in use (0)
  	if (!DeviceIoControl(hid_handle, ioctl_code, buf, expected_size + 1,
  		buf, expected_size + 1, &read_size, overlapped)) {
  		if (GetLastError() != ERROR_IO_PENDING) {
  			usbi_dbg("Failed to Read HID Report: %s", windows_error_str(0));
  			safe_free(buf);
  			return LIBUSB_ERROR_IO;
  		}
  		// Asynchronous wait
  		tp->hid_buffer = buf;
  		tp->hid_dest = data; // copy dest, as not necessarily the start of the transfer buffer
  		return LIBUSB_SUCCESS;
  	}
  
  	// Transfer completed synchronously => copy and discard extra buffer
  	if (read_size == 0) {
  		usbi_warn(NULL, "program assertion failed - read completed synchronously, but no data was read");
  		*size = 0;
  	} else {
  		if (buf[0] != id)
  			usbi_warn(NULL, "mismatched report ID (data is %02X, parameter is %02X)", buf[0], id);
  
  		if ((size_t)read_size > expected_size) {
  			r = LIBUSB_ERROR_OVERFLOW;
  			usbi_dbg("OVERFLOW!");
  		} else {
  			r = LIBUSB_COMPLETED;
  		}
  
  		*size = MIN((size_t)read_size, *size);
  		if (id == 0)
  			memcpy(data, buf + 1, *size); // Discard report ID
  		else
  			memcpy(data, buf, *size);
  	}
  
  	safe_free(buf);
  	return r;
  }
  
  static int _hid_set_report(struct hid_device_priv *dev, HANDLE hid_handle, int id, void *data,
  	struct windows_transfer_priv *tp, size_t *size, OVERLAPPED *overlapped, int report_type)
  {
  	uint8_t *buf = NULL;
  	DWORD ioctl_code, write_size = (DWORD)*size;
  
  	if (tp->hid_buffer != NULL)
  		usbi_dbg("program assertion failed: hid_buffer is not NULL");
  
  	if ((*size == 0) || (*size > MAX_HID_REPORT_SIZE)) {
  		usbi_dbg("invalid size (%u)", *size);
  		return LIBUSB_ERROR_INVALID_PARAM;
  	}
  
  	switch (report_type) {
  	case HID_REPORT_TYPE_OUTPUT:
  		ioctl_code = IOCTL_HID_SET_OUTPUT_REPORT;
  		break;
  	case HID_REPORT_TYPE_FEATURE:
  		ioctl_code = IOCTL_HID_SET_FEATURE;
  		break;
  	default:
  		usbi_dbg("unknown HID report type %d", report_type);
  		return LIBUSB_ERROR_INVALID_PARAM;
  	}
  
  	usbi_dbg("report ID: 0x%02X", id);
  	// When report IDs are not used (i.e. when id == 0), we must add
  	// a null report ID. Otherwise, we just use original data buffer
  	if (id == 0)
  		write_size++;
  
  	buf = malloc(write_size);
  	if (buf == NULL)
  		return LIBUSB_ERROR_NO_MEM;
  
  	if (id == 0) {
  		buf[0] = 0;
  		memcpy(buf + 1, data, *size);
  	} else {
  		// This seems like a waste, but if we don't duplicate the
  		// data, we'll get issues when freeing hid_buffer
  		memcpy(buf, data, *size);
  		if (buf[0] != id)
  			usbi_warn(NULL, "mismatched report ID (data is %02X, parameter is %02X)", buf[0], id);
  	}
  
  	// NB: The size returned by DeviceIoControl doesn't include report IDs when not in use (0)
  	if (!DeviceIoControl(hid_handle, ioctl_code, buf, write_size,
  		buf, write_size, &write_size, overlapped)) {
  		if (GetLastError() != ERROR_IO_PENDING) {
  			usbi_dbg("Failed to Write HID Output Report: %s", windows_error_str(0));
  			safe_free(buf);
  			return LIBUSB_ERROR_IO;
  		}
  		tp->hid_buffer = buf;
  		tp->hid_dest = NULL;
  		return LIBUSB_SUCCESS;
  	}
  
  	// Transfer completed synchronously
  	*size = write_size;
  	if (write_size == 0)
  		usbi_dbg("program assertion failed - write completed synchronously, but no data was written");
  
  	safe_free(buf);
  	return LIBUSB_COMPLETED;
  }
  
  static int _hid_class_request(struct hid_device_priv *dev, HANDLE hid_handle, int request_type,
  	int request, int value, int _index, void *data, struct windows_transfer_priv *tp,
  	size_t *size, OVERLAPPED *overlapped)
  {
  	int report_type = (value >> 8) & 0xFF;
  	int report_id = value & 0xFF;
  
  	if ((LIBUSB_REQ_RECIPIENT(request_type) != LIBUSB_RECIPIENT_INTERFACE)
  			&& (LIBUSB_REQ_RECIPIENT(request_type) != LIBUSB_RECIPIENT_DEVICE))
  		return LIBUSB_ERROR_INVALID_PARAM;
  
  	if (LIBUSB_REQ_OUT(request_type) && request == HID_REQ_SET_REPORT)
  		return _hid_set_report(dev, hid_handle, report_id, data, tp, size, overlapped, report_type);
  
  	if (LIBUSB_REQ_IN(request_type) && request == HID_REQ_GET_REPORT)
  		return _hid_get_report(dev, hid_handle, report_id, data, tp, size, overlapped, report_type);
  
  	return LIBUSB_ERROR_INVALID_PARAM;
  }
  
  
  /*
   * HID API functions
   */
  static int hid_init(int sub_api, struct libusb_context *ctx)
  {
  	DLL_GET_HANDLE(hid);
  	DLL_LOAD_FUNC(hid, HidD_GetAttributes, TRUE);
  	DLL_LOAD_FUNC(hid, HidD_GetHidGuid, TRUE);
  	DLL_LOAD_FUNC(hid, HidD_GetPreparsedData, TRUE);
  	DLL_LOAD_FUNC(hid, HidD_FreePreparsedData, TRUE);
  	DLL_LOAD_FUNC(hid, HidD_GetManufacturerString, TRUE);
  	DLL_LOAD_FUNC(hid, HidD_GetProductString, TRUE);
  	DLL_LOAD_FUNC(hid, HidD_GetSerialNumberString, TRUE);
  	DLL_LOAD_FUNC(hid, HidP_GetCaps, TRUE);
  	DLL_LOAD_FUNC(hid, HidD_SetNumInputBuffers, TRUE);
  	DLL_LOAD_FUNC(hid, HidD_SetFeature, TRUE);
  	DLL_LOAD_FUNC(hid, HidD_GetFeature, TRUE);
  	DLL_LOAD_FUNC(hid, HidD_GetPhysicalDescriptor, TRUE);
  	DLL_LOAD_FUNC(hid, HidD_GetInputReport, FALSE);
  	DLL_LOAD_FUNC(hid, HidD_SetOutputReport, FALSE);
  	DLL_LOAD_FUNC(hid, HidD_FlushQueue, TRUE);
  	DLL_LOAD_FUNC(hid, HidP_GetValueCaps, TRUE);
  
  	api_hid_available = true;
  	return LIBUSB_SUCCESS;
  }
  
  static int hid_exit(int sub_api)
  {
  	DLL_FREE_HANDLE(hid);
  
  	return LIBUSB_SUCCESS;
  }
  
  // NB: open and close must ensure that they only handle interface of
  // the right API type, as these functions can be called wholesale from
  // composite_open(), with interfaces belonging to different APIs
  static int hid_open(int sub_api, struct libusb_device_handle *dev_handle)
  {
  	struct libusb_context *ctx = DEVICE_CTX(dev_handle->dev);
  	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
  	struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
  	HIDD_ATTRIBUTES hid_attributes;
  	PHIDP_PREPARSED_DATA preparsed_data = NULL;
  	HIDP_CAPS capabilities;
  	HIDP_VALUE_CAPS *value_caps;
  	HANDLE hid_handle = INVALID_HANDLE_VALUE;
  	int i, j;
  	// report IDs handling
  	ULONG size[3];
  	int nb_ids[2]; // zero and nonzero report IDs
  #if defined(ENABLE_LOGGING)
  	const char *type[3] = {"input", "output", "feature"};
  #endif
  
  	CHECK_HID_AVAILABLE;
  
  	if (priv->hid == NULL) {
  		usbi_err(ctx, "program assertion failed - private HID structure is unitialized");
  		return LIBUSB_ERROR_NOT_FOUND;
  	}
  
  	for (i = 0; i < USB_MAXINTERFACES; i++) {
  		if ((priv->usb_interface[i].path != NULL)
  				&& (priv->usb_interface[i].apib->id == USB_API_HID)) {
  			hid_handle = CreateFileA(priv->usb_interface[i].path, GENERIC_WRITE | GENERIC_READ, FILE_SHARE_WRITE | FILE_SHARE_READ,
  				NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED, NULL);
  			/*
  			 * http://www.lvr.com/hidfaq.htm: Why do I receive "Access denied" when attempting to access my HID?
  			 * "Windows 2000 and later have exclusive read/write access to HIDs that are configured as a system
  			 * keyboards or mice. An application can obtain a handle to a system keyboard or mouse by not
  			 * requesting READ or WRITE access with CreateFile. Applications can then use HidD_SetFeature and
  			 * HidD_GetFeature (if the device supports Feature reports)."
  			 */
  			if (hid_handle == INVALID_HANDLE_VALUE) {
  				usbi_warn(ctx, "could not open HID device in R/W mode (keyboard or mouse?) - trying without");
  				hid_handle = CreateFileA(priv->usb_interface[i].path, 0, FILE_SHARE_WRITE | FILE_SHARE_READ,
  					NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL | FILE_FLAG_OVERLAPPED, NULL);
  				if (hid_handle == INVALID_HANDLE_VALUE) {
  					usbi_err(ctx, "could not open device %s (interface %d): %s", priv->path, i, windows_error_str(0));
  					switch(GetLastError()) {
  					case ERROR_FILE_NOT_FOUND: // The device was disconnected
  						return LIBUSB_ERROR_NO_DEVICE;
  					case ERROR_ACCESS_DENIED:
  						return LIBUSB_ERROR_ACCESS;
  					default:
  						return LIBUSB_ERROR_IO;
  					}
  				}
  				priv->usb_interface[i].restricted_functionality = true;
  			}
  			handle_priv->interface_handle[i].api_handle = hid_handle;
  		}
  	}
  
  	hid_attributes.Size = sizeof(hid_attributes);
  	do {
  		if (!HidD_GetAttributes(hid_handle, &hid_attributes)) {
  			usbi_err(ctx, "could not gain access to HID top collection (HidD_GetAttributes)");
  			break;
  		}
  
  		priv->hid->vid = hid_attributes.VendorID;
  		priv->hid->pid = hid_attributes.ProductID;
  
  		// Set the maximum available input buffer size
  		for (i = 32; HidD_SetNumInputBuffers(hid_handle, i); i *= 2);
  		usbi_dbg("set maximum input buffer size to %d", i / 2);
  
  		// Get the maximum input and output report size
  		if (!HidD_GetPreparsedData(hid_handle, &preparsed_data) || !preparsed_data) {
  			usbi_err(ctx, "could not read HID preparsed data (HidD_GetPreparsedData)");
  			break;
  		}
  		if (HidP_GetCaps(preparsed_data, &capabilities) != HIDP_STATUS_SUCCESS) {
  			usbi_err(ctx, "could not parse HID capabilities (HidP_GetCaps)");
  			break;
  		}
  
  		// Find out if interrupt will need report IDs
  		size[0] = capabilities.NumberInputValueCaps;
  		size[1] = capabilities.NumberOutputValueCaps;
  		size[2] = capabilities.NumberFeatureValueCaps;
  		for (j = HidP_Input; j <= HidP_Feature; j++) {
  			usbi_dbg("%u HID %s report value(s) found", (unsigned int)size[j], type[j]);
  			priv->hid->uses_report_ids[j] = false;
  			if (size[j] > 0) {
  				value_caps = calloc(size[j], sizeof(HIDP_VALUE_CAPS));
  				if ((value_caps != NULL)
  						&& (HidP_GetValueCaps((HIDP_REPORT_TYPE)j, value_caps, &size[j], preparsed_data) == HIDP_STATUS_SUCCESS)
  						&& (size[j] >= 1)) {
  					nb_ids[0] = 0;
  					nb_ids[1] = 0;
  					for (i = 0; i < (int)size[j]; i++) {
  						usbi_dbg("  Report ID: 0x%02X", value_caps[i].ReportID);
  						if (value_caps[i].ReportID != 0)
  							nb_ids[1]++;
  						else
  							nb_ids[0]++;
  					}
  					if (nb_ids[1] != 0) {
  						if (nb_ids[0] != 0)
  							usbi_warn(ctx, "program assertion failed: zero and nonzero report IDs used for %s",
  								type[j]);
  						priv->hid->uses_report_ids[j] = true;
  					}
  				} else {
  					usbi_warn(ctx, "  could not process %s report IDs", type[j]);
  				}
  				safe_free(value_caps);
  			}
  		}
  
  		// Set the report sizes
  		priv->hid->input_report_size = capabilities.InputReportByteLength;
  		priv->hid->output_report_size = capabilities.OutputReportByteLength;
  		priv->hid->feature_report_size = capabilities.FeatureReportByteLength;
  
  		// Fetch string descriptors
  		priv->hid->string_index[0] = priv->dev_descriptor.iManufacturer;
  		if (priv->hid->string_index[0] != 0)
  			HidD_GetManufacturerString(hid_handle, priv->hid->string[0], sizeof(priv->hid->string[0]));
  		else
  			priv->hid->string[0][0] = 0;
  
  		priv->hid->string_index[1] = priv->dev_descriptor.iProduct;
  		if (priv->hid->string_index[1] != 0)
  			HidD_GetProductString(hid_handle, priv->hid->string[1], sizeof(priv->hid->string[1]));
  		else
  			priv->hid->string[1][0] = 0;
  
  		priv->hid->string_index[2] = priv->dev_descriptor.iSerialNumber;
  		if (priv->hid->string_index[2] != 0)
  			HidD_GetSerialNumberString(hid_handle, priv->hid->string[2], sizeof(priv->hid->string[2]));
  		else
  			priv->hid->string[2][0] = 0;
  	} while(0);
  
  	if (preparsed_data)
  		HidD_FreePreparsedData(preparsed_data);
  
  	return LIBUSB_SUCCESS;
  }
  
  static void hid_close(int sub_api, struct libusb_device_handle *dev_handle)
  {
  	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
  	struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
  	HANDLE file_handle;
  	int i;
  
  	if (!api_hid_available)
  		return;
  
  	for (i = 0; i < USB_MAXINTERFACES; i++) {
  		if (priv->usb_interface[i].apib->id == USB_API_HID) {
  			file_handle = handle_priv->interface_handle[i].api_handle;
  			if (HANDLE_VALID(file_handle))
  				CloseHandle(file_handle);
  		}
  	}
  }
  
  static int hid_claim_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface)
  {
  	struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
  	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
  
  	CHECK_HID_AVAILABLE;
  
  	// NB: Disconnection detection is not possible in this function
  	if (priv->usb_interface[iface].path == NULL)
  		return LIBUSB_ERROR_NOT_FOUND; // invalid iface
  
  	// We use dev_handle as a flag for interface claimed
  	if (handle_priv->interface_handle[iface].dev_handle == INTERFACE_CLAIMED)
  		return LIBUSB_ERROR_BUSY; // already claimed
  
  
  	handle_priv->interface_handle[iface].dev_handle = INTERFACE_CLAIMED;
  
  	usbi_dbg("claimed interface %d", iface);
  	handle_priv->active_interface = iface;
  
  	return LIBUSB_SUCCESS;
  }
  
  static int hid_release_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface)
  {
  	struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
  	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
  
  	CHECK_HID_AVAILABLE;
  
  	if (priv->usb_interface[iface].path == NULL)
  		return LIBUSB_ERROR_NOT_FOUND; // invalid iface
  
  	if (handle_priv->interface_handle[iface].dev_handle != INTERFACE_CLAIMED)
  		return LIBUSB_ERROR_NOT_FOUND; // invalid iface
  
  	handle_priv->interface_handle[iface].dev_handle = INVALID_HANDLE_VALUE;
  
  	return LIBUSB_SUCCESS;
  }
  
  static int hid_set_interface_altsetting(int sub_api, struct libusb_device_handle *dev_handle, int iface, int altsetting)
  {
  	struct libusb_context *ctx = DEVICE_CTX(dev_handle->dev);
  
  	CHECK_HID_AVAILABLE;
  
  	if (altsetting > 255)
  		return LIBUSB_ERROR_INVALID_PARAM;
  
  	if (altsetting != 0) {
  		usbi_err(ctx, "set interface altsetting not supported for altsetting >0");
  		return LIBUSB_ERROR_NOT_SUPPORTED;
  	}
  
  	return LIBUSB_SUCCESS;
  }
  
  static int hid_submit_control_transfer(int sub_api, struct usbi_transfer *itransfer)
  {
  	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
  	struct windows_transfer_priv *transfer_priv = usbi_transfer_get_os_priv(itransfer);
  	struct windows_device_handle_priv *handle_priv = _device_handle_priv(transfer->dev_handle);
  	struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
  	struct libusb_context *ctx = DEVICE_CTX(transfer->dev_handle->dev);
  	WINUSB_SETUP_PACKET *setup = (WINUSB_SETUP_PACKET *)transfer->buffer;
  	HANDLE hid_handle;
  	struct winfd wfd;
  	int current_interface, config;
  	size_t size;
  	int r = LIBUSB_ERROR_INVALID_PARAM;
  
  	CHECK_HID_AVAILABLE;
  
  	transfer_priv->pollable_fd = INVALID_WINFD;
  	safe_free(transfer_priv->hid_buffer);
  	transfer_priv->hid_dest = NULL;
  	size = transfer->length - LIBUSB_CONTROL_SETUP_SIZE;
  
  	if (size > MAX_CTRL_BUFFER_LENGTH)
  		return LIBUSB_ERROR_INVALID_PARAM;
  
  	current_interface = get_valid_interface(transfer->dev_handle, USB_API_HID);
  	if (current_interface < 0) {
  		if (auto_claim(transfer, &current_interface, USB_API_HID) != LIBUSB_SUCCESS)
  			return LIBUSB_ERROR_NOT_FOUND;
  	}
  
  	usbi_dbg("will use interface %d", current_interface);
  	hid_handle = handle_priv->interface_handle[current_interface].api_handle;
  	// Always use the handle returned from usbi_create_fd (wfd.handle)
  	wfd = usbi_create_fd(hid_handle, RW_READ, NULL, NULL);
  	if (wfd.fd < 0)
  		return LIBUSB_ERROR_NOT_FOUND;
  
  	switch(LIBUSB_REQ_TYPE(setup->request_type)) {
  	case LIBUSB_REQUEST_TYPE_STANDARD:
  		switch(setup->request) {
  		case LIBUSB_REQUEST_GET_DESCRIPTOR:
  			r = _hid_get_descriptor(priv->hid, wfd.handle, LIBUSB_REQ_RECIPIENT(setup->request_type),
  				(setup->value >> 8) & 0xFF, setup->value & 0xFF, transfer->buffer + LIBUSB_CONTROL_SETUP_SIZE, &size);
  			break;
  		case LIBUSB_REQUEST_GET_CONFIGURATION:
  			r = windows_get_configuration(transfer->dev_handle, &config);
  			if (r == LIBUSB_SUCCESS) {
  				size = 1;
  				((uint8_t *)transfer->buffer)[LIBUSB_CONTROL_SETUP_SIZE] = (uint8_t)config;
  				r = LIBUSB_COMPLETED;
  			}
  			break;
  		case LIBUSB_REQUEST_SET_CONFIGURATION:
  			if (setup->value == priv->active_config) {
  				r = LIBUSB_COMPLETED;
  			} else {
  				usbi_warn(ctx, "cannot set configuration other than the default one");
  				r = LIBUSB_ERROR_NOT_SUPPORTED;
  			}
  			break;
  		case LIBUSB_REQUEST_GET_INTERFACE:
  			size = 1;
  			((uint8_t *)transfer->buffer)[LIBUSB_CONTROL_SETUP_SIZE] = 0;
  			r = LIBUSB_COMPLETED;
  			break;
  		case LIBUSB_REQUEST_SET_INTERFACE:
  			r = hid_set_interface_altsetting(0, transfer->dev_handle, setup->index, setup->value);
  			if (r == LIBUSB_SUCCESS)
  				r = LIBUSB_COMPLETED;
  			break;
  		default:
  			usbi_warn(ctx, "unsupported HID control request");
  			r = LIBUSB_ERROR_NOT_SUPPORTED;
  			break;
  		}
  		break;
  	case LIBUSB_REQUEST_TYPE_CLASS:
  		r = _hid_class_request(priv->hid, wfd.handle, setup->request_type, setup->request, setup->value,
  			setup->index, transfer->buffer + LIBUSB_CONTROL_SETUP_SIZE, transfer_priv,
  			&size, wfd.overlapped);
  		break;
  	default:
  		usbi_warn(ctx, "unsupported HID control request");
  		r = LIBUSB_ERROR_NOT_SUPPORTED;
  		break;
  	}
  
  	if (r == LIBUSB_COMPLETED) {
  		// Force request to be completed synchronously. Transferred size has been set by previous call
  		wfd.overlapped->Internal = STATUS_COMPLETED_SYNCHRONOUSLY;
  		// http://msdn.microsoft.com/en-us/library/ms684342%28VS.85%29.aspx
  		// set InternalHigh to the number of bytes transferred
  		wfd.overlapped->InternalHigh = (DWORD)size;
  		r = LIBUSB_SUCCESS;
  	}
  
  	if (r == LIBUSB_SUCCESS) {
  		// Use priv_transfer to store data needed for async polling
  		transfer_priv->pollable_fd = wfd;
  		transfer_priv->interface_number = (uint8_t)current_interface;
  	} else {
  		usbi_free_fd(&wfd);
  	}
  
  	return r;
  }
  
  static int hid_submit_bulk_transfer(int sub_api, struct usbi_transfer *itransfer)
  {
  	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
  	struct windows_transfer_priv *transfer_priv = usbi_transfer_get_os_priv(itransfer);
  	struct libusb_context *ctx = DEVICE_CTX(transfer->dev_handle->dev);
  	struct windows_device_handle_priv *handle_priv = _device_handle_priv(transfer->dev_handle);
  	struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
  	struct winfd wfd;
  	HANDLE hid_handle;
  	bool direction_in, ret;
  	int current_interface, length;
  	DWORD size;
  	int r = LIBUSB_SUCCESS;
  
  	CHECK_HID_AVAILABLE;
  
  	transfer_priv->pollable_fd = INVALID_WINFD;
  	transfer_priv->hid_dest = NULL;
  	safe_free(transfer_priv->hid_buffer);
  
  	current_interface = interface_by_endpoint(priv, handle_priv, transfer->endpoint);
  	if (current_interface < 0) {
  		usbi_err(ctx, "unable to match endpoint to an open interface - cancelling transfer");
  		return LIBUSB_ERROR_NOT_FOUND;
  	}
  
  	usbi_dbg("matched endpoint %02X with interface %d", transfer->endpoint, current_interface);
  
  	hid_handle = handle_priv->interface_handle[current_interface].api_handle;
  	direction_in = transfer->endpoint & LIBUSB_ENDPOINT_IN;
  
  	wfd = usbi_create_fd(hid_handle, direction_in?RW_READ:RW_WRITE, NULL, NULL);
  	// Always use the handle returned from usbi_create_fd (wfd.handle)
  	if (wfd.fd < 0)
  		return LIBUSB_ERROR_NO_MEM;
  
  	// If report IDs are not in use, an extra prefix byte must be added
  	if (((direction_in) && (!priv->hid->uses_report_ids[0]))
  			|| ((!direction_in) && (!priv->hid->uses_report_ids[1])))
  		length = transfer->length + 1;
  	else
  		length = transfer->length;
  
  	// Add a trailing byte to detect overflows on input
  	transfer_priv->hid_buffer = calloc(1, length + 1);
  	if (transfer_priv->hid_buffer == NULL)
  		return LIBUSB_ERROR_NO_MEM;
  
  	transfer_priv->hid_expected_size = length;
  
  	if (direction_in) {
  		transfer_priv->hid_dest = transfer->buffer;
  		usbi_dbg("reading %d bytes (report ID: 0x00)", length);
  		ret = ReadFile(wfd.handle, transfer_priv->hid_buffer, length + 1, &size, wfd.overlapped);
  	} else {
  		if (!priv->hid->uses_report_ids[1])
  			memcpy(transfer_priv->hid_buffer + 1, transfer->buffer, transfer->length);
  		else
  			// We could actually do without the calloc and memcpy in this case
  			memcpy(transfer_priv->hid_buffer, transfer->buffer, transfer->length);
  
  		usbi_dbg("writing %d bytes (report ID: 0x%02X)", length, transfer_priv->hid_buffer[0]);
  		ret = WriteFile(wfd.handle, transfer_priv->hid_buffer, length, &size, wfd.overlapped);
  	}
  
  	if (!ret) {
  		if (GetLastError() != ERROR_IO_PENDING) {
  			usbi_err(ctx, "HID transfer failed: %s", windows_error_str(0));
  			usbi_free_fd(&wfd);
  			safe_free(transfer_priv->hid_buffer);
  			return LIBUSB_ERROR_IO;
  		}
  	} else {
  		// Only write operations that completed synchronously need to free up
  		// hid_buffer. For reads, copy_transfer_data() handles that process.
  		if (!direction_in)
  			safe_free(transfer_priv->hid_buffer);
  
  		if (size == 0) {
  			usbi_err(ctx, "program assertion failed - no data was transferred");
  			size = 1;
  		}
  		if (size > (size_t)length) {
  			usbi_err(ctx, "OVERFLOW!");
  			r = LIBUSB_ERROR_OVERFLOW;
  		}
  		wfd.overlapped->Internal = STATUS_COMPLETED_SYNCHRONOUSLY;
  		wfd.overlapped->InternalHigh = size;
  	}
  
  	transfer_priv->pollable_fd = wfd;
  	transfer_priv->interface_number = (uint8_t)current_interface;
  
  	return r;
  }
  
  static int hid_abort_transfers(int sub_api, struct usbi_transfer *itransfer)
  {
  	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
  	struct windows_transfer_priv *transfer_priv = usbi_transfer_get_os_priv(itransfer);
  	struct windows_device_handle_priv *handle_priv = _device_handle_priv(transfer->dev_handle);
  	HANDLE hid_handle;
  	int current_interface;
  
  	CHECK_HID_AVAILABLE;
  
  	current_interface = transfer_priv->interface_number;
  	hid_handle = handle_priv->interface_handle[current_interface].api_handle;
  	CancelIo(hid_handle);
  
  	return LIBUSB_SUCCESS;
  }
  
  static int hid_reset_device(int sub_api, struct libusb_device_handle *dev_handle)
  {
  	struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
  	HANDLE hid_handle;
  	int current_interface;
  
  	CHECK_HID_AVAILABLE;
  
  	// Flushing the queues on all interfaces is the best we can achieve
  	for (current_interface = 0; current_interface < USB_MAXINTERFACES; current_interface++) {
  		hid_handle = handle_priv->interface_handle[current_interface].api_handle;
  		if (HANDLE_VALID(hid_handle))
  			HidD_FlushQueue(hid_handle);
  	}
  
  	return LIBUSB_SUCCESS;
  }
  
  static int hid_clear_halt(int sub_api, struct libusb_device_handle *dev_handle, unsigned char endpoint)
  {
  	struct libusb_context *ctx = DEVICE_CTX(dev_handle->dev);
  	struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
  	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
  	HANDLE hid_handle;
  	int current_interface;
  
  	CHECK_HID_AVAILABLE;
  
  	current_interface = interface_by_endpoint(priv, handle_priv, endpoint);
  	if (current_interface < 0) {
  		usbi_err(ctx, "unable to match endpoint to an open interface - cannot clear");
  		return LIBUSB_ERROR_NOT_FOUND;
  	}
  
  	usbi_dbg("matched endpoint %02X with interface %d", endpoint, current_interface);
  	hid_handle = handle_priv->interface_handle[current_interface].api_handle;
  
  	// No endpoint selection with Microsoft's implementation, so we try to flush the
  	// whole interface. Should be OK for most case scenarios
  	if (!HidD_FlushQueue(hid_handle)) {
  		usbi_err(ctx, "Flushing of HID queue failed: %s", windows_error_str(0));
  		// Device was probably disconnected
  		return LIBUSB_ERROR_NO_DEVICE;
  	}
  
  	return LIBUSB_SUCCESS;
  }
  
  // This extra function is only needed for HID
  static int hid_copy_transfer_data(int sub_api, struct usbi_transfer *itransfer, uint32_t io_size)
  {
  	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
  	struct libusb_context *ctx = DEVICE_CTX(transfer->dev_handle->dev);
  	struct windows_transfer_priv *transfer_priv = usbi_transfer_get_os_priv(itransfer);
  	int r = LIBUSB_TRANSFER_COMPLETED;
  	uint32_t corrected_size = io_size;
  
  	if (transfer_priv->hid_buffer != NULL) {
  		// If we have a valid hid_buffer, it means the transfer was async
  		if (transfer_priv->hid_dest != NULL) { // Data readout
  			if (corrected_size > 0) {
  				// First, check for overflow
  				if (corrected_size > transfer_priv->hid_expected_size) {
  					usbi_err(ctx, "OVERFLOW!");
  					corrected_size = (uint32_t)transfer_priv->hid_expected_size;
  					r = LIBUSB_TRANSFER_OVERFLOW;
  				}
  
  				if (transfer_priv->hid_buffer[0] == 0) {
  					// Discard the 1 byte report ID prefix
  					corrected_size--;
  					memcpy(transfer_priv->hid_dest, transfer_priv->hid_buffer + 1, corrected_size);
  				} else {
  					memcpy(transfer_priv->hid_dest, transfer_priv->hid_buffer, corrected_size);
  				}
  			}
  			transfer_priv->hid_dest = NULL;
  		}
  		// For write, we just need to free the hid buffer
  		safe_free(transfer_priv->hid_buffer);
  	}
  
  	itransfer->transferred += corrected_size;
  	return r;
  }
  
  
  /*
   * Composite API functions
   */
  static int composite_init(int sub_api, struct libusb_context *ctx)
  {
  	return LIBUSB_SUCCESS;
  }
  
  static int composite_exit(int sub_api)
  {
  	return LIBUSB_SUCCESS;
  }
  
  static int composite_open(int sub_api, struct libusb_device_handle *dev_handle)
  {
  	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
  	int r = LIBUSB_ERROR_NOT_FOUND;
  	uint8_t i;
  	// SUB_API_MAX + 1 as the SUB_API_MAX pos is used to indicate availability of HID
  	bool available[SUB_API_MAX + 1] = { 0 };
  
  	for (i = 0; i < USB_MAXINTERFACES; i++) {
  		switch (priv->usb_interface[i].apib->id) {
  		case USB_API_WINUSBX:
  			if (priv->usb_interface[i].sub_api != SUB_API_NOTSET)
  				available[priv->usb_interface[i].sub_api] = true;
  			break;
  		case USB_API_HID:
  			available[SUB_API_MAX] = true;
  			break;
  		default:
  			break;
  		}
  	}
  
  	for (i = 0; i < SUB_API_MAX; i++) { // WinUSB-like drivers
  		if (available[i]) {
  			r = usb_api_backend[USB_API_WINUSBX].open(i, dev_handle);
  			if (r != LIBUSB_SUCCESS)
  				return r;
  		}
  	}
  
  	if (available[SUB_API_MAX]) // HID driver
  		r = hid_open(SUB_API_NOTSET, dev_handle);
  
  	return r;
  }
  
  static void composite_close(int sub_api, struct libusb_device_handle *dev_handle)
  {
  	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
  	uint8_t i;
  	// SUB_API_MAX + 1 as the SUB_API_MAX pos is used to indicate availability of HID
  	bool available[SUB_API_MAX + 1] = { 0 };
  
  	for (i = 0; i < USB_MAXINTERFACES; i++) {
  		switch (priv->usb_interface[i].apib->id) {
  		case USB_API_WINUSBX:
  			if (priv->usb_interface[i].sub_api != SUB_API_NOTSET)
  				available[priv->usb_interface[i].sub_api] = true;
  			break;
  		case USB_API_HID:
  			available[SUB_API_MAX] = true;
  			break;
  		default:
  			break;
  		}
  	}
  
  	for (i = 0; i < SUB_API_MAX; i++) { // WinUSB-like drivers
  		if (available[i])
  			usb_api_backend[USB_API_WINUSBX].close(i, dev_handle);
  	}
  
  	if (available[SUB_API_MAX]) // HID driver
  		hid_close(SUB_API_NOTSET, dev_handle);
  }
  
  static int composite_claim_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface)
  {
  	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
  
  	return priv->usb_interface[iface].apib->
  		claim_interface(priv->usb_interface[iface].sub_api, dev_handle, iface);
  }
  
  static int composite_set_interface_altsetting(int sub_api, struct libusb_device_handle *dev_handle, int iface, int altsetting)
  {
  	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
  
  	return priv->usb_interface[iface].apib->
  		set_interface_altsetting(priv->usb_interface[iface].sub_api, dev_handle, iface, altsetting);
  }
  
  static int composite_release_interface(int sub_api, struct libusb_device_handle *dev_handle, int iface)
  {
  	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
  
  	return priv->usb_interface[iface].apib->
  		release_interface(priv->usb_interface[iface].sub_api, dev_handle, iface);
  }
  
  static int composite_submit_control_transfer(int sub_api, struct usbi_transfer *itransfer)
  {
  	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
  	struct libusb_context *ctx = DEVICE_CTX(transfer->dev_handle->dev);
  	struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
  	struct libusb_config_descriptor *conf_desc;
  	WINUSB_SETUP_PACKET *setup = (WINUSB_SETUP_PACKET *)transfer->buffer;
  	int iface, pass, r;
  
  	// Interface shouldn't matter for control, but it does in practice, with Windows'
  	// restrictions with regards to accessing HID keyboards and mice. Try to target
  	// a specific interface first, if possible.
  	switch (LIBUSB_REQ_RECIPIENT(setup->request_type)) {
  	case LIBUSB_RECIPIENT_INTERFACE:
  		iface = setup->index & 0xFF;
  		break;
  	case LIBUSB_RECIPIENT_ENDPOINT:
  		r = libusb_get_active_config_descriptor(transfer->dev_handle->dev, &conf_desc);
  		if (r == LIBUSB_SUCCESS) {
  			iface = get_interface_by_endpoint(conf_desc, (setup->index & 0xFF));
  			libusb_free_config_descriptor(conf_desc);
  			break;
  		}
  		// Fall through if not able to determine interface
  	default:
  		iface = -1;
  		break;
  	}
  
  	// Try and target a specific interface if the control setup indicates such
  	if ((iface >= 0) && (iface < USB_MAXINTERFACES)) {
  		usbi_dbg("attempting control transfer targeted to interface %d", iface);
  		if (priv->usb_interface[iface].path != NULL) {
  			r = priv->usb_interface[iface].apib->submit_control_transfer(priv->usb_interface[iface].sub_api, itransfer);
  			if (r == LIBUSB_SUCCESS)
  				return r;
  		}
  	}
  
  	// Either not targeted to a specific interface or no luck in doing so.
  	// Try a 2 pass approach with all interfaces.
  	for (pass = 0; pass < 2; pass++) {
  		for (iface = 0; iface < USB_MAXINTERFACES; iface++) {
  			if (priv->usb_interface[iface].path != NULL) {
  				if ((pass == 0) && (priv->usb_interface[iface].restricted_functionality)) {
  					usbi_dbg("trying to skip restricted interface #%d (HID keyboard or mouse?)", iface);
  					continue;
  				}
  				usbi_dbg("using interface %d", iface);
  				r = priv->usb_interface[iface].apib->submit_control_transfer(priv->usb_interface[iface].sub_api, itransfer);
  				// If not supported on this API, it may be supported on another, so don't give up yet!!
  				if (r == LIBUSB_ERROR_NOT_SUPPORTED)
  					continue;
  				return r;
  			}
  		}
  	}
  
  	usbi_err(ctx, "no libusb supported interfaces to complete request");
  	return LIBUSB_ERROR_NOT_FOUND;
  }
  
  static int composite_submit_bulk_transfer(int sub_api, struct usbi_transfer *itransfer) {
  	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
  	struct libusb_context *ctx = DEVICE_CTX(transfer->dev_handle->dev);
  	struct windows_device_handle_priv *handle_priv = _device_handle_priv(transfer->dev_handle);
  	struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
  	int current_interface;
  
  	current_interface = interface_by_endpoint(priv, handle_priv, transfer->endpoint);
  	if (current_interface < 0) {
  		usbi_err(ctx, "unable to match endpoint to an open interface - cancelling transfer");
  		return LIBUSB_ERROR_NOT_FOUND;
  	}
  
  	return priv->usb_interface[current_interface].apib->
  		submit_bulk_transfer(priv->usb_interface[current_interface].sub_api, itransfer);
  }
  
  static int composite_submit_iso_transfer(int sub_api, struct usbi_transfer *itransfer) {
  	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
  	struct libusb_context *ctx = DEVICE_CTX(transfer->dev_handle->dev);
  	struct windows_device_handle_priv *handle_priv = _device_handle_priv(transfer->dev_handle);
  	struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
  	int current_interface;
  
  	current_interface = interface_by_endpoint(priv, handle_priv, transfer->endpoint);
  	if (current_interface < 0) {
  		usbi_err(ctx, "unable to match endpoint to an open interface - cancelling transfer");
  		return LIBUSB_ERROR_NOT_FOUND;
  	}
  
  	return priv->usb_interface[current_interface].apib->
  		submit_iso_transfer(priv->usb_interface[current_interface].sub_api, itransfer);
  }
  
  static int composite_clear_halt(int sub_api, struct libusb_device_handle *dev_handle, unsigned char endpoint)
  {
  	struct libusb_context *ctx = DEVICE_CTX(dev_handle->dev);
  	struct windows_device_handle_priv *handle_priv = _device_handle_priv(dev_handle);
  	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
  	int current_interface;
  
  	current_interface = interface_by_endpoint(priv, handle_priv, endpoint);
  	if (current_interface < 0) {
  		usbi_err(ctx, "unable to match endpoint to an open interface - cannot clear");
  		return LIBUSB_ERROR_NOT_FOUND;
  	}
  
  	return priv->usb_interface[current_interface].apib->
  		clear_halt(priv->usb_interface[current_interface].sub_api, dev_handle, endpoint);
  }
  
  static int composite_abort_control(int sub_api, struct usbi_transfer *itransfer)
  {
  	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
  	struct windows_transfer_priv *transfer_priv = usbi_transfer_get_os_priv(itransfer);
  	struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
  
  	return priv->usb_interface[transfer_priv->interface_number].apib->
  		abort_control(priv->usb_interface[transfer_priv->interface_number].sub_api, itransfer);
  }
  
  static int composite_abort_transfers(int sub_api, struct usbi_transfer *itransfer)
  {
  	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
  	struct windows_transfer_priv *transfer_priv = usbi_transfer_get_os_priv(itransfer);
  	struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
  
  	return priv->usb_interface[transfer_priv->interface_number].apib->
  		abort_transfers(priv->usb_interface[transfer_priv->interface_number].sub_api, itransfer);
  }
  
  static int composite_reset_device(int sub_api, struct libusb_device_handle *dev_handle)
  {
  	struct windows_device_priv *priv = _device_priv(dev_handle->dev);
  	int r;
  	uint8_t i;
  	bool available[SUB_API_MAX];
  
  	for (i = 0; i < SUB_API_MAX; i++)
  		available[i] = false;
  
  	for (i = 0; i < USB_MAXINTERFACES; i++) {
  		if ((priv->usb_interface[i].apib->id == USB_API_WINUSBX)
  				&& (priv->usb_interface[i].sub_api != SUB_API_NOTSET))
  			available[priv->usb_interface[i].sub_api] = true;
  	}
  
  	for (i = 0; i < SUB_API_MAX; i++) {
  		if (available[i]) {
  			r = usb_api_backend[USB_API_WINUSBX].reset_device(i, dev_handle);
  			if (r != LIBUSB_SUCCESS)
  				return r;
  		}
  	}
  
  	return LIBUSB_SUCCESS;
  }
  
  static int composite_copy_transfer_data(int sub_api, struct usbi_transfer *itransfer, uint32_t io_size)
  {
  	struct libusb_transfer *transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
  	struct windows_transfer_priv *transfer_priv = usbi_transfer_get_os_priv(itransfer);
  	struct windows_device_priv *priv = _device_priv(transfer->dev_handle->dev);
  
  	return priv->usb_interface[transfer_priv->interface_number].apib->
  		copy_transfer_data(priv->usb_interface[transfer_priv->interface_number].sub_api, itransfer, io_size);
  }
  
  #endif /* !USE_USBDK */
  