HID Device to UDP

gistfile1.m

#import <Foundation/Foundation.h>
#import <IOKit/hid/IOHIDManager.h>
#import <IOKit/hid/IOHIDUsageTables.h>

#define KEYS 4


static void Handle_InputCallback(void *inContext, IOReturn inResult, void *inSender, IOHIDValueRef value)
{   
    IOHIDElementRef elem = IOHIDValueGetElement(value);

    uint16_t scancode = IOHIDElementGetUsage(elem);
    
    if (scancode < 4 || scancode > 231) {
        return;
    }
    
    NSLog(@"Key event received");
}


static void Handle_DeviceMatchingCallback(void * inContext, IOReturn inResult, void * inSender, IOHIDDeviceRef inIOHIDDeviceRef)
{
    NSLog(@"Connected");
}

static void Handle_RemovalCallback(void * inContext, IOReturn inResult, void * inSender, IOHIDDeviceRef inIOHIDDeviceRef)
{
    NSLog(@"Removed");
}


int main(int argc, const char * argv[])
{
    @autoreleasepool {
        IOHIDManagerRef manager = IOHIDManagerCreate(kCFAllocatorDefault, kIOHIDManagerOptionNone);
        
        if (CFGetTypeID(manager) != IOHIDManagerGetTypeID()) {
            exit(1);
        }
        
        int vendorId = 0x05ac;
        //vendorId = 0x1234;
        int productId = 0x0237;
        //productId = 0x5678;
        int usagePage = kHIDPage_GenericDesktop;
        int usage = kHIDUsage_GD_Keyboard;
        
        CFStringRef keys[KEYS] = {
            CFSTR(kIOHIDVendorIDKey),
            CFSTR(kIOHIDProductIDKey),
            CFSTR(kIOHIDDeviceUsagePageKey),
            CFSTR(kIOHIDDeviceUsageKey),
        };
        
        CFNumberRef values[KEYS] = {
            CFNumberCreate(kCFAllocatorDefault, kCFNumberSInt32Type, &vendorId),
            CFNumberCreate(kCFAllocatorDefault, kCFNumberSInt32Type, &productId),
            CFNumberCreate(kCFAllocatorDefault, kCFNumberSInt32Type, &usagePage),
            CFNumberCreate(kCFAllocatorDefault, kCFNumberSInt32Type, &usage),
        };
        
        CFDictionaryRef matchingDict = CFDictionaryCreate(kCFAllocatorDefault,
                                                          (const void **) keys, (const void **) values, KEYS,
                                                          &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks);

        for (int i=0; i<KEYS; i++) {
            CFRelease(keys[i]);
            CFRelease(values[i]);
        }
        
        IOHIDManagerSetDeviceMatching(manager, matchingDict);
        CFRelease(matchingDict);
        
        IOHIDManagerRegisterDeviceMatchingCallback(manager, Handle_DeviceMatchingCallback, null);
        IOHIDManagerRegisterDeviceRemovalCallback(manager, Handle_RemovalCallback, null);
        IOHIDManagerRegisterInputValueCallback(manager, Handle_InputCallback, null);
        
        IOHIDManagerOpen(manager, kIOHIDOptionsTypeSeizeDevice);

        IOHIDManagerScheduleWithRunLoop(manager, CFRunLoopGetCurrent(), kCFRunLoopDefaultMode);
    
        [[NSRunLoop mainRunLoop] run];
    }
    return 0;
}