Added iOS/tvOS hidapi 0.14.0 support

src/hidapi/SDL_hidapi.c

@@ -1633,6 +1633,7 @@ int SDL_hid_get_report_descriptor(SDL_hid_device *device, unsigned char *buf, si
 void SDL_hid_ble_scan(SDL_bool active)
 {
 #if !defined(SDL_HIDAPI_DISABLED) && (defined(__IOS__) || defined(__TVOS__))
+    extern void hid_ble_scan(int bStart);
     hid_ble_scan(active);
 #endif
 }

src/hidapi/ios/hid.m

@@ -0,0 +1,1038 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 2021 Valve Corporation
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+#include "SDL_internal.h"
+
+#ifndef SDL_HIDAPI_DISABLED
+
+
+#define hid_close                    PLATFORM_hid_close
+#define hid_device                   PLATFORM_hid_device
+#define hid_device_                  PLATFORM_hid_device_
+#define hid_enumerate                PLATFORM_hid_enumerate
+#define hid_error                    PLATFORM_hid_error
+#define hid_exit                     PLATFORM_hid_exit
+#define hid_free_enumeration         PLATFORM_hid_free_enumeration
+#define hid_get_device_info          PLATFORM_hid_get_device_info
+#define hid_get_feature_report       PLATFORM_hid_get_feature_report
+#define hid_get_indexed_string       PLATFORM_hid_get_indexed_string
+#define hid_get_input_report         PLATFORM_hid_get_input_report
+#define hid_get_manufacturer_string  PLATFORM_hid_get_manufacturer_string
+#define hid_get_product_string       PLATFORM_hid_get_product_string
+#define hid_get_report_descriptor    PLATFORM_hid_get_report_descriptor
+#define hid_get_serial_number_string PLATFORM_hid_get_serial_number_string
+#define hid_init                     PLATFORM_hid_init
+#define hid_open_path                PLATFORM_hid_open_path
+#define hid_open                     PLATFORM_hid_open
+#define hid_read                     PLATFORM_hid_read
+#define hid_read_timeout             PLATFORM_hid_read_timeout
+#define hid_send_feature_report      PLATFORM_hid_send_feature_report
+#define hid_set_nonblocking          PLATFORM_hid_set_nonblocking
+#define hid_version                  PLATFORM_hid_version
+#define hid_version_str              PLATFORM_hid_version_str
+#define hid_write                    PLATFORM_hid_write
+
+#include <CoreBluetooth/CoreBluetooth.h>
+#include <QuartzCore/QuartzCore.h>
+#import <UIKit/UIKit.h>
+#import <mach/mach_time.h>
+#include <pthread.h>
+#include <sys/time.h>
+#include <unistd.h>
+#include "../hidapi/hidapi.h"
+
+#define VALVE_USB_VID       0x28DE
+#define D0G_BLE2_PID        0x1106
+
+typedef uint32_t uint32;
+typedef uint64_t uint64;
+
+// enables detailed NSLog logging of feature reports
+#define FEATURE_REPORT_LOGGING	0
+
+#define REPORT_SEGMENT_DATA_FLAG	0x80
+#define REPORT_SEGMENT_LAST_FLAG	0x40
+
+#define VALVE_SERVICE		@"100F6C32-1735-4313-B402-38567131E5F3"
+
+// (READ/NOTIFICATIONS)
+#define VALVE_INPUT_CHAR	@"100F6C33-1735-4313-B402-38567131E5F3"
+
+//  (READ/WRITE)
+#define VALVE_REPORT_CHAR	@"100F6C34-1735-4313-B402-38567131E5F3"
+
+// TODO: create CBUUID's in __attribute__((constructor)) rather than doing [CBUUID UUIDWithString:...] everywhere
+
+#pragma pack(push,1)
+
+typedef struct
+{
+	uint8_t		segmentHeader;
+	uint8_t		featureReportMessageID;
+	uint8_t		length;
+	uint8_t		settingIdentifier;
+	union {
+		uint16_t	usPayload;
+		uint32_t	uPayload;
+		uint64_t	ulPayload;
+		uint8_t		ucPayload[15];
+	};
+} bluetoothSegment;
+
+typedef struct {
+	uint8_t		id;
+	union {
+		bluetoothSegment segment;
+		struct {
+			uint8_t		segmentHeader;
+			uint8_t		featureReportMessageID;
+			uint8_t		length;
+			uint8_t		settingIdentifier;
+			union {
+				uint16_t	usPayload;
+				uint32_t	uPayload;
+				uint64_t	ulPayload;
+				uint8_t		ucPayload[15];
+			};
+		};
+	};
+} hidFeatureReport;
+
+#pragma pack(pop)
+
+size_t GetBluetoothSegmentSize(bluetoothSegment *segment)
+{
+    return segment->length + 3;
+}
+
+#define RingBuffer_cbElem   19
+#define RingBuffer_nElem    4096
+
+typedef struct {
+	int _first, _last;
+	uint8_t _data[ ( RingBuffer_nElem * RingBuffer_cbElem ) ];
+	pthread_mutex_t accessLock;
+} RingBuffer;
+
+static void RingBuffer_init( RingBuffer *this )
+{
+    this->_first = -1;
+    this->_last = 0;
+    pthread_mutex_init( &this->accessLock, 0 );
+}
+
+static bool RingBuffer_write( RingBuffer *this, const uint8_t *src )
+{
+    pthread_mutex_lock( &this->accessLock );
+    memcpy( &this->_data[ this->_last ], src, RingBuffer_cbElem );
+    if ( this->_first == -1 )
+    {
+        this->_first = this->_last;
+    }
+    this->_last = ( this->_last + RingBuffer_cbElem ) % (RingBuffer_nElem * RingBuffer_cbElem);
+    if ( this->_last == this->_first )
+    {
+        this->_first = ( this->_first + RingBuffer_cbElem ) % (RingBuffer_nElem * RingBuffer_cbElem);
+        pthread_mutex_unlock( &this->accessLock );
+        return false;
+    }
+    pthread_mutex_unlock( &this->accessLock );
+    return true;
+}
+
+static bool RingBuffer_read( RingBuffer *this, uint8_t *dst )
+{
+    pthread_mutex_lock( &this->accessLock );
+    if ( this->_first == -1 )
+    {
+        pthread_mutex_unlock( &this->accessLock );
+        return false;
+    }
+    memcpy( dst, &this->_data[ this->_first ], RingBuffer_cbElem );
+    this->_first = ( this->_first + RingBuffer_cbElem ) % (RingBuffer_nElem * RingBuffer_cbElem);
+    if ( this->_first == this->_last )
+    {
+        this->_first = -1;
+    }
+    pthread_mutex_unlock( &this->accessLock );
+    return true;
+}
+
+
+#pragma mark HIDBLEDevice Definition
+
+typedef enum
+{
+	BLEDeviceWaitState_None,
+	BLEDeviceWaitState_Waiting,
+	BLEDeviceWaitState_Complete,
+	BLEDeviceWaitState_Error
+} BLEDeviceWaitState;
+
+@interface HIDBLEDevice : NSObject <CBPeripheralDelegate>
+{
+	RingBuffer _inputReports;
+	uint8_t	_featureReport[20];
+	BLEDeviceWaitState	_waitStateForReadFeatureReport;
+	BLEDeviceWaitState	_waitStateForWriteFeatureReport;
+}
+
+@property (nonatomic, readwrite) bool connected;
+@property (nonatomic, readwrite) bool ready;
+
+@property (nonatomic, strong) CBPeripheral     *bleSteamController;
+@property (nonatomic, strong) CBCharacteristic *bleCharacteristicInput;
+@property (nonatomic, strong) CBCharacteristic *bleCharacteristicReport;
+
+- (id)initWithPeripheral:(CBPeripheral *)peripheral;
+
+@end
+
+
+@interface HIDBLEManager : NSObject <CBCentralManagerDelegate>
+
+@property (nonatomic) int nPendingScans;
+@property (nonatomic) int nPendingPairs;
+@property (nonatomic, strong) CBCentralManager *centralManager;
+@property (nonatomic, strong) NSMapTable<CBPeripheral *, HIDBLEDevice *> *deviceMap;
+@property (nonatomic, retain) dispatch_queue_t bleSerialQueue;
+
++ (instancetype)sharedInstance;
+- (void)startScan:(int)duration;
+- (void)stopScan;
+- (int)updateConnectedSteamControllers:(BOOL) bForce;
+- (void)appWillResignActiveNotification:(NSNotification *)note;
+- (void)appDidBecomeActiveNotification:(NSNotification *)note;
+
+@end
+
+
+// singleton class - access using HIDBLEManager.sharedInstance
+@implementation HIDBLEManager
+
++ (instancetype)sharedInstance
+{
+	static HIDBLEManager *sharedInstance = nil;
+	static dispatch_once_t onceToken;
+	dispatch_once(&onceToken, ^{
+		sharedInstance = [HIDBLEManager new];
+		sharedInstance.nPendingScans = 0;
+		sharedInstance.nPendingPairs = 0;
+
+        // Bluetooth is currently only used for Steam Controllers, so check that hint
+        // before initializing Bluetooth, which will prompt the user for permission.
+		if ( SDL_GetHintBoolean( SDL_HINT_JOYSTICK_HIDAPI_STEAM, SDL_FALSE ) )
+		{
+			[[NSNotificationCenter defaultCenter] addObserver:sharedInstance selector:@selector(appWillResignActiveNotification:) name: UIApplicationWillResignActiveNotification object:nil];
+			[[NSNotificationCenter defaultCenter] addObserver:sharedInstance selector:@selector(appDidBecomeActiveNotification:) name:UIApplicationDidBecomeActiveNotification object:nil];
+
+			// receive reports on a high-priority serial-queue. optionally put writes on the serial queue to avoid logical
+			// race conditions talking to the controller from multiple threads, although BLE fragmentation/assembly means
+			// that we can still screw this up.
+			// most importantly we need to consume reports at a high priority to avoid the OS thinking we aren't really
+			// listening to the BLE device, as iOS on slower devices may stop delivery of packets to the app WITHOUT ACTUALLY
+			// DISCONNECTING FROM THE DEVICE if we don't react quickly enough to their delivery.
+			// see also the error-handling states in the peripheral delegate to re-open the device if it gets closed
+			sharedInstance.bleSerialQueue = dispatch_queue_create( "com.valvesoftware.steamcontroller.ble", DISPATCH_QUEUE_SERIAL );
+			dispatch_set_target_queue( sharedInstance.bleSerialQueue, dispatch_get_global_queue( DISPATCH_QUEUE_PRIORITY_HIGH, 0 ) );
+
+			// creating a CBCentralManager will always trigger a future centralManagerDidUpdateState:
+			// where any scanning gets started or connecting to existing peripherals happens, it's never already in a
+			// powered-on state for a newly launched application.
+			sharedInstance.centralManager = [[CBCentralManager alloc] initWithDelegate:sharedInstance queue:sharedInstance.bleSerialQueue];
+		}
+		sharedInstance.deviceMap = [[NSMapTable alloc] initWithKeyOptions:NSMapTableWeakMemory valueOptions:NSMapTableStrongMemory capacity:4];
+	});
+	return sharedInstance;
+}
+
+// called for NSNotification UIApplicationWillResignActiveNotification
+- (void)appWillResignActiveNotification:(NSNotification *)note
+{
+	// we'll get resign-active notification if pairing is happening.
+	if ( self.nPendingPairs > 0 )
+		return;
+
+	for ( CBPeripheral *peripheral in self.deviceMap )
+	{
+		HIDBLEDevice *steamController = [self.deviceMap objectForKey:peripheral];
+		if ( steamController )
+		{
+			steamController.connected = NO;
+			steamController.ready = NO;
+			[self.centralManager cancelPeripheralConnection:peripheral];
+		}
+	}
+	[self.deviceMap removeAllObjects];
+}
+
+// called for NSNotification UIApplicationDidBecomeActiveNotification
+//  whenever the application comes back from being inactive, trigger a 20s pairing scan and reconnect
+//  any devices that may have paired while we were inactive.
+- (void)appDidBecomeActiveNotification:(NSNotification *)note
+{
+	[self updateConnectedSteamControllers:true];
+	[self startScan:20];
+}
+
+- (int)updateConnectedSteamControllers:(BOOL) bForce
+{
+	static uint64_t s_unLastUpdateTick = 0;
+	static mach_timebase_info_data_t s_timebase_info;
+
+	if ( self.centralManager == nil )
+    {
+		return 0;
+    }
+
+	if (s_timebase_info.denom == 0)
+	{
+		mach_timebase_info( &s_timebase_info );
+	}
+
+	uint64_t ticksNow = mach_approximate_time();
+	if ( !bForce && ( ( (ticksNow - s_unLastUpdateTick) * s_timebase_info.numer ) / s_timebase_info.denom ) < (5ull * NSEC_PER_SEC) )
+		return (int)self.deviceMap.count;
+
+	// we can see previously connected BLE peripherals but can't connect until the CBCentralManager
+	// is fully powered up - only do work when we are in that state
+	if ( self.centralManager.state != CBManagerStatePoweredOn )
+		return (int)self.deviceMap.count;
+
+	// only update our last-check-time if we actually did work, otherwise there can be a long delay during initial power-up
+	s_unLastUpdateTick = mach_approximate_time();
+
+	// if a pair is in-flight, the central manager may still give it back via retrieveConnected... and
+	// cause the SDL layer to attempt to initialize it while some of its endpoints haven't yet been established
+	if ( self.nPendingPairs > 0 )
+		return (int)self.deviceMap.count;
+
+	NSArray<CBPeripheral *> *peripherals = [self.centralManager retrieveConnectedPeripheralsWithServices: @[ [CBUUID UUIDWithString:@"180A"]]];
+	for ( CBPeripheral *peripheral in peripherals )
+	{
+		// we already know this peripheral
+		if ( [self.deviceMap objectForKey: peripheral] != nil )
+			continue;
+
+		NSLog( @"connected peripheral: %@", peripheral );
+		if ( [peripheral.name isEqualToString:@"SteamController"] )
+		{
+			self.nPendingPairs += 1;
+			HIDBLEDevice *steamController = [[HIDBLEDevice alloc] initWithPeripheral:peripheral];
+			[self.deviceMap setObject:steamController forKey:peripheral];
+			[self.centralManager connectPeripheral:peripheral options:nil];
+		}
+	}
+
+	return (int)self.deviceMap.count;
+}
+
+// manual API for folks to start & stop scanning
+- (void)startScan:(int)duration
+{
+	if ( self.centralManager == nil )
+	{
+		return;
+	}
+
+	NSLog( @"BLE: requesting scan for %d seconds", duration );
+	@synchronized (self)
+	{
+		if ( _nPendingScans++ == 0 )
+		{
+			[self.centralManager scanForPeripheralsWithServices:nil options:nil];
+		}
+	}
+
+	if ( duration != 0 )
+	{
+		dispatch_after( dispatch_time( DISPATCH_TIME_NOW, (int64_t)(duration * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
+			[self stopScan];
+		});
+	}
+}
+
+- (void)stopScan
+{
+	if ( self.centralManager == nil )
+	{
+		return;
+	}
+
+	NSLog( @"BLE: stopping scan" );
+	@synchronized (self)
+	{
+		if ( --_nPendingScans <= 0 )
+		{
+			_nPendingScans = 0;
+			[self.centralManager stopScan];
+		}
+	}
+}
+
+
+#pragma mark CBCentralManagerDelegate Implementation
+
+// called whenever the BLE hardware state changes.
+- (void)centralManagerDidUpdateState:(CBCentralManager *)central
+{
+	switch ( central.state )
+	{
+		case CBCentralManagerStatePoweredOn:
+		{
+			NSLog( @"CoreBluetooth BLE hardware is powered on and ready" );
+
+			// at startup, if we have no already attached peripherals, do a 20s scan for new unpaired devices,
+			// otherwise callers should occaisionally do additional scans. we don't want to continuously be
+			// scanning because it drains battery, causes other nearby people to have a hard time pairing their
+			// Steam Controllers, and may also trigger firmware weirdness when a device attempts to start
+			// the pairing sequence multiple times concurrently
+			if ( [self updateConnectedSteamControllers:false] == 0 )
+			{
+				// TODO: we could limit our scan to only peripherals supporting the SteamController service, but
+				//  that service doesn't currently fit in the base advertising packet, we'd need to put it into an
+				//  extended scan packet. Useful optimization downstream, but not currently necessary
+				//	NSArray *services = @[[CBUUID UUIDWithString:VALVE_SERVICE]];
+				[self startScan:20];
+			}
+			break;
+		}
+
+		case CBCentralManagerStatePoweredOff:
+			NSLog( @"CoreBluetooth BLE hardware is powered off" );
+			break;
+
+		case CBCentralManagerStateUnauthorized:
+			NSLog( @"CoreBluetooth BLE state is unauthorized" );
+			break;
+
+		case CBCentralManagerStateUnknown:
+			NSLog( @"CoreBluetooth BLE state is unknown" );
+			break;
+
+		case CBCentralManagerStateUnsupported:
+			NSLog( @"CoreBluetooth BLE hardware is unsupported on this platform" );
+			break;
+
+		case CBCentralManagerStateResetting:
+			NSLog( @"CoreBluetooth BLE manager is resetting" );
+			break;
+	}
+}
+
+- (void)centralManager:(CBCentralManager *)central didConnectPeripheral:(CBPeripheral *)peripheral
+{
+	HIDBLEDevice *steamController = [_deviceMap objectForKey:peripheral];
+	steamController.connected = YES;
+	self.nPendingPairs -= 1;
+}
+
+- (void)centralManager:(CBCentralManager *)central didFailToConnectPeripheral:(CBPeripheral *)peripheral error:(NSError *)error
+{
+	NSLog( @"Failed to connect: %@", error );
+	[_deviceMap removeObjectForKey:peripheral];
+	self.nPendingPairs -= 1;
+}
+
+- (void)centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral *)peripheral advertisementData:(NSDictionary *)advertisementData RSSI:(NSNumber *)RSSI
+{
+	NSString *localName = [advertisementData objectForKey:CBAdvertisementDataLocalNameKey];
+	NSString *log = [NSString stringWithFormat:@"Found '%@'", localName];
+
+	if ( [localName isEqualToString:@"SteamController"] )
+	{
+		NSLog( @"%@ : %@ - %@", log, peripheral, advertisementData );
+		self.nPendingPairs += 1;
+		HIDBLEDevice *steamController = [[HIDBLEDevice alloc] initWithPeripheral:peripheral];
+		[self.deviceMap setObject:steamController forKey:peripheral];
+		[self.centralManager connectPeripheral:peripheral options:nil];
+	}
+}
+
+- (void)centralManager:(CBCentralManager *)central didDisconnectPeripheral:(CBPeripheral *)peripheral error:(NSError *)error
+{
+	HIDBLEDevice *steamController = [self.deviceMap objectForKey:peripheral];
+	if ( steamController )
+	{
+		steamController.connected = NO;
+		steamController.ready = NO;
+		[self.deviceMap removeObjectForKey:peripheral];
+	}
+}
+
+@end
+
+
+// Core Bluetooth devices calling back on event boundaries of their run-loops. so annoying.
+static void process_pending_events(void)
+{
+	CFRunLoopRunResult res;
+	do
+	{
+		res = CFRunLoopRunInMode( kCFRunLoopDefaultMode, 0.001, FALSE );
+	}
+	while( res != kCFRunLoopRunFinished && res != kCFRunLoopRunTimedOut );
+}
+
+@implementation HIDBLEDevice
+
+- (id)init
+{
+	if ( self = [super init] )
+	{
+        RingBuffer_init( &_inputReports );
+		self.bleSteamController = nil;
+		self.bleCharacteristicInput = nil;
+		self.bleCharacteristicReport = nil;
+		_connected = NO;
+		_ready = NO;
+	}
+	return self;
+}
+
+- (id)initWithPeripheral:(CBPeripheral *)peripheral
+{
+	if ( self = [super init] )
+	{
+        RingBuffer_init( &_inputReports );
+		_connected = NO;
+		_ready = NO;
+		self.bleSteamController = peripheral;
+		if ( peripheral )
+		{
+			peripheral.delegate = self;
+		}
+		self.bleCharacteristicInput = nil;
+		self.bleCharacteristicReport = nil;
+	}
+	return self;
+}
+
+- (void)setConnected:(bool)connected
+{
+	_connected = connected;
+	if ( _connected )
+	{
+		[_bleSteamController discoverServices:nil];
+	}
+	else
+	{
+		NSLog( @"Disconnected" );
+	}
+}
+
+- (size_t)read_input_report:(uint8_t *)dst
+{
+	if ( RingBuffer_read( &_inputReports, dst+1 ) )
+	{
+		*dst = 0x03;
+		return 20;
+	}
+	return 0;
+}
+
+- (int)send_report:(const uint8_t *)data length:(size_t)length
+{
+	[_bleSteamController writeValue:[NSData dataWithBytes:data length:length] forCharacteristic:_bleCharacteristicReport type:CBCharacteristicWriteWithResponse];
+	return (int)length;
+}
+
+- (int)send_feature_report:(hidFeatureReport *)report
+{
+#if FEATURE_REPORT_LOGGING
+	uint8_t *reportBytes = (uint8_t *)report;
+
+	NSLog( @"HIDBLE:send_feature_report (%02zu/19) [%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x]", GetBluetoothSegmentSize( report->segment ),
+		  reportBytes[1], reportBytes[2], reportBytes[3], reportBytes[4], reportBytes[5], reportBytes[6],
+		  reportBytes[7], reportBytes[8], reportBytes[9], reportBytes[10], reportBytes[11], reportBytes[12],
+		  reportBytes[13], reportBytes[14], reportBytes[15], reportBytes[16], reportBytes[17], reportBytes[18],
+		  reportBytes[19] );
+#endif
+
+	int sendSize = (int)GetBluetoothSegmentSize( &report->segment );
+	if ( sendSize > 20 )
+		sendSize = 20;
+
+#if 1
+	// fire-and-forget - we are going to not wait for the response here because all Steam Controller BLE send_feature_report's are ignored,
+	//  except errors.
+	[_bleSteamController writeValue:[NSData dataWithBytes:&report->segment length:sendSize] forCharacteristic:_bleCharacteristicReport type:CBCharacteristicWriteWithResponse];
+
+	// pretend we received a result anybody cares about
+	return 19;
+
+#else
+	// this is technically the correct send_feature_report logic if you want to make sure it gets through and is
+	// acknowledged or errors out
+	_waitStateForWriteFeatureReport = BLEDeviceWaitState_Waiting;
+	[_bleSteamController writeValue:[NSData dataWithBytes:&report->segment length:sendSize
+									 ] forCharacteristic:_bleCharacteristicReport type:CBCharacteristicWriteWithResponse];
+
+	while ( _waitStateForWriteFeatureReport == BLEDeviceWaitState_Waiting )
+	{
+		process_pending_events();
+	}
+
+	if ( _waitStateForWriteFeatureReport == BLEDeviceWaitState_Error )
+	{
+		_waitStateForWriteFeatureReport = BLEDeviceWaitState_None;
+		return -1;
+	}
+
+	_waitStateForWriteFeatureReport = BLEDeviceWaitState_None;
+	return 19;
+#endif
+}
+
+- (int)get_feature_report:(uint8_t)feature into:(uint8_t *)buffer
+{
+	_waitStateForReadFeatureReport = BLEDeviceWaitState_Waiting;
+	[_bleSteamController readValueForCharacteristic:_bleCharacteristicReport];
+
+	while ( _waitStateForReadFeatureReport == BLEDeviceWaitState_Waiting )
+		process_pending_events();
+
+	if ( _waitStateForReadFeatureReport == BLEDeviceWaitState_Error )
+	{
+		_waitStateForReadFeatureReport = BLEDeviceWaitState_None;
+		return -1;
+	}
+
+	memcpy( buffer, _featureReport, sizeof(_featureReport) );
+
+	_waitStateForReadFeatureReport = BLEDeviceWaitState_None;
+
+#if FEATURE_REPORT_LOGGING
+	NSLog( @"HIDBLE:get_feature_report (19) [%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x]",
+		  buffer[1], buffer[2], buffer[3], buffer[4], buffer[5], buffer[6],
+		  buffer[7], buffer[8], buffer[9], buffer[10], buffer[11], buffer[12],
+		  buffer[13], buffer[14], buffer[15], buffer[16], buffer[17], buffer[18],
+		  buffer[19] );
+#endif
+
+	return 19;
+}
+
+#pragma mark CBPeripheralDelegate Implementation
+
+- (void)peripheral:(CBPeripheral *)peripheral didDiscoverServices:(NSError *)error
+{
+	for (CBService *service in peripheral.services)
+	{
+		NSLog( @"Found Service: %@", service );
+		if ( [service.UUID isEqual:[CBUUID UUIDWithString:VALVE_SERVICE]] )
+		{
+			[peripheral discoverCharacteristics:nil forService:service];
+		}
+	}
+}
+
+- (void)peripheral:(CBPeripheral *)peripheral didDiscoverDescriptorsForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error
+{
+	// nothing yet needed here, enable for logging
+	if ( /* DISABLES CODE */ (0) )
+	{
+		for ( CBDescriptor *descriptor in characteristic.descriptors )
+		{
+			NSLog( @" - Descriptor '%@'", descriptor );
+		}
+	}
+}
+
+- (void)peripheral:(CBPeripheral *)peripheral didDiscoverCharacteristicsForService:(CBService *)service error:(NSError *)error
+{
+	if ([service.UUID isEqual:[CBUUID UUIDWithString:VALVE_SERVICE]])
+	{
+		for (CBCharacteristic *aChar in service.characteristics)
+		{
+			NSLog( @"Found Characteristic %@", aChar );
+
+			if ( [aChar.UUID isEqual:[CBUUID UUIDWithString:VALVE_INPUT_CHAR]] )
+			{
+				self.bleCharacteristicInput = aChar;
+			}
+			else if ( [aChar.UUID isEqual:[CBUUID UUIDWithString:VALVE_REPORT_CHAR]] )
+			{
+				self.bleCharacteristicReport = aChar;
+				[self.bleSteamController discoverDescriptorsForCharacteristic: aChar];
+			}
+		}
+	}
+}
+
+- (void)peripheral:(CBPeripheral *)peripheral didUpdateValueForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error
+{
+	static uint64_t s_ticksLastOverflowReport = 0;
+
+	// receiving an input report is the final indicator that the user accepted a pairing
+	// request and that we successfully established notification. CoreBluetooth has no
+	// notification of the pairing acknowledgement, which is a bad oversight.
+	if ( self.ready == NO )
+	{
+		self.ready = YES;
+		HIDBLEManager.sharedInstance.nPendingPairs -= 1;
+	}
+
+	if ( [characteristic.UUID isEqual:_bleCharacteristicInput.UUID] )
+	{
+		NSData *data = [characteristic value];
+		if ( data.length != 19 )
+		{
+			NSLog( @"HIDBLE: incoming data is %lu bytes should be exactly 19", (unsigned long)data.length );
+		}
+		if ( !RingBuffer_write( &_inputReports, (const uint8_t *)data.bytes ) )
+		{
+			uint64_t ticksNow = mach_approximate_time();
+			if ( ticksNow - s_ticksLastOverflowReport > (5ull * NSEC_PER_SEC / 10) )
+			{
+				NSLog( @"HIDBLE: input report buffer overflow" );
+				s_ticksLastOverflowReport = ticksNow;
+			}
+		}
+	}
+	else if ( [characteristic.UUID isEqual:_bleCharacteristicReport.UUID] )
+	{
+		memset( _featureReport, 0, sizeof(_featureReport) );
+
+		if ( error != nil )
+		{
+			NSLog( @"HIDBLE: get_feature_report error: %@", error );
+			_waitStateForReadFeatureReport = BLEDeviceWaitState_Error;
+		}
+		else
+		{
+			NSData *data = [characteristic value];
+			if ( data.length != 20 )
+			{
+				NSLog( @"HIDBLE: incoming data is %lu bytes should be exactly 20", (unsigned long)data.length );
+			}
+			memcpy( _featureReport, data.bytes, MIN( data.length, sizeof(_featureReport) ) );
+			_waitStateForReadFeatureReport = BLEDeviceWaitState_Complete;
+		}
+	}
+}
+
+- (void)peripheral:(CBPeripheral *)peripheral didWriteValueForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error
+{
+	if ( [characteristic.UUID isEqual:[CBUUID UUIDWithString:VALVE_REPORT_CHAR]] )
+	{
+		if ( error != nil )
+		{
+			NSLog( @"HIDBLE: write_feature_report error: %@", error );
+			_waitStateForWriteFeatureReport = BLEDeviceWaitState_Error;
+		}
+		else
+		{
+			_waitStateForWriteFeatureReport = BLEDeviceWaitState_Complete;
+		}
+	}
+}
+
+- (void)peripheral:(CBPeripheral *)peripheral didUpdateNotificationStateForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error
+{
+	NSLog( @"didUpdateNotifcationStateForCharacteristic %@ (%@)", characteristic, error );
+}
+
+@end
+
+
+#pragma mark hid_api implementation
+
+struct hid_device_ {
+	void *device_handle;
+	int blocking;
+	struct hid_device_info* device_info;
+	hid_device *next;
+};
+
+int HID_API_EXPORT HID_API_CALL hid_init(void)
+{
+	return ( HIDBLEManager.sharedInstance == nil ) ? -1 : 0;
+}
+
+int HID_API_EXPORT HID_API_CALL hid_exit(void)
+{
+	return 0;
+}
+
+void HID_API_EXPORT HID_API_CALL hid_ble_scan( int bStart )
+{
+	HIDBLEManager *bleManager = HIDBLEManager.sharedInstance;
+	if ( bStart )
+	{
+		[bleManager startScan:0];
+	}
+	else
+	{
+		[bleManager stopScan];
+	}
+}
+
+HID_API_EXPORT hid_device * HID_API_CALL hid_open(unsigned short vendor_id, unsigned short product_id, const wchar_t *serial_number)
+{
+	return NULL;
+}
+
+HID_API_EXPORT hid_device * HID_API_CALL hid_open_path( const char *path )
+{
+	hid_device *result = NULL;
+	NSString *nssPath = [NSString stringWithUTF8String:path];
+	HIDBLEManager *bleManager = HIDBLEManager.sharedInstance;
+	NSEnumerator<HIDBLEDevice *> *devices = [bleManager.deviceMap objectEnumerator];
+
+	for ( HIDBLEDevice *device in devices )
+	{
+		// we have the device but it hasn't found its service or characteristics until it is connected
+		if ( !device.ready || !device.connected || !device.bleCharacteristicInput )
+			continue;
+
+		if ( [device.bleSteamController.identifier.UUIDString isEqualToString:nssPath] )
+		{
+			result = (hid_device *)malloc( sizeof( hid_device ) );
+			memset( result, 0, sizeof( hid_device ) );
+			result->device_handle = (void*)CFBridgingRetain( device );
+			result->blocking = NO;
+			// enable reporting input events on the characteristic
+			[device.bleSteamController setNotifyValue:YES forCharacteristic:device.bleCharacteristicInput];
+			return result;
+		}
+	}
+	return result;
+}
+
+void  HID_API_EXPORT hid_free_enumeration(struct hid_device_info *devs)
+{
+	/* This function is identical to the Linux version. Platform independent. */
+	struct hid_device_info *d = devs;
+	while (d) {
+		struct hid_device_info *next = d->next;
+		free(d->path);
+		free(d->serial_number);
+		free(d->manufacturer_string);
+		free(d->product_string);
+		free(d);
+		d = next;
+	}
+}
+
+int HID_API_EXPORT hid_set_nonblocking(hid_device *dev, int nonblock)
+{
+	/* All Nonblocking operation is handled by the library. */
+	dev->blocking = !nonblock;
+
+	return 0;
+}
+
+static struct hid_device_info *create_device_info_for_hid_device(HIDBLEDevice *device)
+{
+    // We currently only support the Steam Controller
+    struct hid_device_info *device_info = (struct hid_device_info *)malloc( sizeof(struct hid_device_info) );
+    memset( device_info, 0, sizeof(struct hid_device_info) );
+    device_info->path = strdup( device.bleSteamController.identifier.UUIDString.UTF8String );
+    device_info->vendor_id = VALVE_USB_VID;
+    device_info->product_id = D0G_BLE2_PID;
+    device_info->product_string = wcsdup( L"Steam Controller" );
+    device_info->manufacturer_string = wcsdup( L"Valve Corporation" );
+    return device_info;
+}
+
+struct hid_device_info  HID_API_EXPORT *hid_enumerate(unsigned short vendor_id, unsigned short product_id)
+{ @autoreleasepool {
+	struct hid_device_info *root = NULL;
+	const char *hint = SDL_GetHint(SDL_HINT_HIDAPI_IGNORE_DEVICES);
+
+	/* See if there are any devices we should skip in enumeration */
+	if (hint) {
+		char vendor_match[16], product_match[16];
+		SDL_snprintf(vendor_match, sizeof(vendor_match), "0x%.4x/0x0000", VALVE_USB_VID);
+		SDL_snprintf(product_match, sizeof(product_match), "0x%.4x/0x%.4x", VALVE_USB_VID, D0G_BLE2_PID);
+		if (SDL_strcasestr(hint, vendor_match) || SDL_strcasestr(hint, product_match)) {
+			return NULL;
+		}
+	}
+
+	if ( ( vendor_id == 0 && product_id == 0 ) ||
+		 ( vendor_id == VALVE_USB_VID && product_id == D0G_BLE2_PID ) )
+	{
+		HIDBLEManager *bleManager = HIDBLEManager.sharedInstance;
+		[bleManager updateConnectedSteamControllers:false];
+		NSEnumerator<HIDBLEDevice *> *devices = [bleManager.deviceMap objectEnumerator];
+		for ( HIDBLEDevice *device in devices )
+		{
+			// there are several brief windows in connecting to an already paired device and
+			// one long window waiting for users to confirm pairing where we don't want
+			// to consider a device ready - if we hand it back to SDL or another
+			// Steam Controller consumer, their additional SC setup work will fail
+			// in unusual/silent ways and we can actually corrupt the BLE stack for
+			// the entire system and kill the appletv remote's Menu button (!)
+			if ( device.bleSteamController.state != CBPeripheralStateConnected ||
+				 device.connected == NO || device.ready == NO )
+			{
+				if ( device.ready == NO && device.bleCharacteristicInput != nil )
+				{
+					// attempt to register for input reports. this call will silently fail
+					// until the pairing finalizes with user acceptance. oh, apple.
+					[device.bleSteamController setNotifyValue:YES forCharacteristic:device.bleCharacteristicInput];
+				}
+				continue;
+			}
+			struct hid_device_info *device_info = create_device_info_for_hid_device(device);
+			device_info->next = root;
+			root = device_info;
+		}
+	}
+	return root;
+}}
+
+int HID_API_EXPORT_CALL hid_get_manufacturer_string(hid_device *dev, wchar_t *string, size_t maxlen)
+{
+	static wchar_t s_wszManufacturer[] = L"Valve Corporation";
+	wcsncpy( string, s_wszManufacturer, sizeof(s_wszManufacturer)/sizeof(s_wszManufacturer[0]) );
+	return 0;
+}
+
+int HID_API_EXPORT_CALL hid_get_product_string(hid_device *dev, wchar_t *string, size_t maxlen)
+{
+	static wchar_t s_wszProduct[] = L"Steam Controller";
+	wcsncpy( string, s_wszProduct, sizeof(s_wszProduct)/sizeof(s_wszProduct[0]) );
+	return 0;
+}
+
+int HID_API_EXPORT_CALL hid_get_serial_number_string(hid_device *dev, wchar_t *string, size_t maxlen)
+{
+	static wchar_t s_wszSerial[] = L"12345";
+	wcsncpy( string, s_wszSerial, sizeof(s_wszSerial)/sizeof(s_wszSerial[0]) );
+	return 0;
+}
+
+int HID_API_EXPORT_CALL hid_get_indexed_string(hid_device *dev, int string_index, wchar_t *string, size_t maxlen)
+{
+	return -1;
+}
+
+struct hid_device_info *hid_get_device_info(hid_device *dev)
+{
+    HIDBLEDevice *device_handle = (__bridge HIDBLEDevice *)dev->device_handle;
+
+	if (!dev->device_info) {
+		// Lazy initialize device_info
+		dev->device_info = create_device_info_for_hid_device(device_handle);
+	}
+
+	// create_device_info_for_hid_device will set an error if needed
+	return dev->device_info;
+}
+
+int hid_get_report_descriptor(hid_device *device, unsigned char *buf, size_t buf_size)
+{
+    // Not implemented
+    return -1;
+}
+
+int HID_API_EXPORT hid_write(hid_device *dev, const unsigned char *data, size_t length)
+{
+    HIDBLEDevice *device_handle = (__bridge HIDBLEDevice *)dev->device_handle;
+
+	if ( !device_handle.connected )
+		return -1;
+
+	return [device_handle send_report:data length:length];
+}
+
+void HID_API_EXPORT hid_close(hid_device *dev)
+{
+    HIDBLEDevice *device_handle = CFBridgingRelease( dev->device_handle );
+
+	// disable reporting input events on the characteristic
+	if ( device_handle.connected ) {
+		[device_handle.bleSteamController setNotifyValue:NO forCharacteristic:device_handle.bleCharacteristicInput];
+	}
+
+    hid_free_enumeration(dev->device_info);
+
+	free( dev );
+}
+
+int HID_API_EXPORT hid_send_feature_report(hid_device *dev, const unsigned char *data, size_t length)
+{
+    HIDBLEDevice *device_handle = (__bridge HIDBLEDevice *)dev->device_handle;
+
+	if ( !device_handle.connected )
+		return -1;
+
+	return [device_handle send_feature_report:(hidFeatureReport *)(void *)data];
+}
+
+int HID_API_EXPORT hid_get_feature_report(hid_device *dev, unsigned char *data, size_t length)
+{
+    HIDBLEDevice *device_handle = (__bridge HIDBLEDevice *)dev->device_handle;
+
+	if ( !device_handle.connected )
+		return -1;
+
+	size_t written = [device_handle get_feature_report:data[0] into:data];
+
+	return written == length-1 ? (int)length : (int)written;
+}
+
+int HID_API_EXPORT hid_get_input_report(hid_device *dev, unsigned char *data, size_t length)
+{
+    // Not supported
+    return -1;
+}
+
+int HID_API_EXPORT hid_read(hid_device *dev, unsigned char *data, size_t length)
+{
+    HIDBLEDevice *device_handle = (__bridge HIDBLEDevice *)dev->device_handle;
+
+	if ( !device_handle.connected )
+		return -1;
+
+	return hid_read_timeout(dev, data, length, 0);
+}
+
+int HID_API_EXPORT hid_read_timeout(hid_device *dev, unsigned char *data, size_t length, int milliseconds)
+{
+    HIDBLEDevice *device_handle = (__bridge HIDBLEDevice *)dev->device_handle;
+
+	if ( !device_handle.connected )
+		return -1;
+
+	if ( milliseconds != 0 )
+	{
+		NSLog( @"hid_read_timeout with non-zero wait" );
+	}
+	int result = (int)[device_handle read_input_report:data];
+#if FEATURE_REPORT_LOGGING
+	NSLog( @"HIDBLE:hid_read_timeout (%d) [%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x]", result,
+		  data[1], data[2], data[3], data[4], data[5], data[6],
+		  data[7], data[8], data[9], data[10], data[11], data[12],
+		  data[13], data[14], data[15], data[16], data[17], data[18],
+		  data[19] );
+#endif
+	return result;
+}
+
+HID_API_EXPORT const wchar_t* HID_API_CALL hid_error(hid_device *dev)
+{
+	return NULL;
+}
+
+#endif /* !SDL_HIDAPI_DISABLED */