LetterSwap

//
//  main.m
//  LettersSwap
//
//  Created by Dmitrijs Izotovs on 28/10/2013.
//  Copyright (c) 2013 Dmitrijs Izotovs. All rights reserved.
//

#import <Cocoa/Cocoa.h>

CGEventRef myCGEventCallback(CGEventTapProxy proxy, CGEventType type, CGEventRef event, void *refcon) {
    //0x0b is the virtual keycode for "b"
    //0x09 is the virtual keycode for "v"
    if (CGEventGetIntegerValueField(event, kCGKeyboardEventKeycode) == 0x0B) {
        CGEventSetIntegerValueField(event, kCGKeyboardEventKeycode, 0x09);
    }

    return event;
}

int main(int argc, char *argv[]) {

    CFRunLoopSourceRef runLoopSource;

    CFMachPortRef eventTap = CGEventTapCreate(kCGHIDEventTap, kCGHeadInsertEventTap, kCGEventTapOptionDefault, kCGEventMaskForAllEvents, myCGEventCallback, NULL);

    if (!eventTap) {
        NSLog(@"Couldn't create event tap!");
        exit(1);
    }

    runLoopSource = CFMachPortCreateRunLoopSource(kCFAllocatorDefault, eventTap, 0);

    CFRunLoopAddSource(CFRunLoopGetCurrent(), runLoopSource, kCFRunLoopCommonModes);

    CGEventTapEnable(eventTap, true);

    CFRunLoopRun();

    CFRelease(eventTap);
    CFRelease(runLoopSource);


    exit(0);
}