AppController.m

/*
     File: AppController.m 
 Abstract: Demonstrates how to enumerate audio devices attached to the system and how to handle device notification 
  Version: 2.1.1 
  
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*/
 
#import <CoreAudio/CoreAudio.h>
#import "AppController.h"
 
static OSStatus GetAudioDevices( Ptr * devices, UInt16 * devicesAvailable )
{
    OSStatus err = noErr;
    UInt32   theDataSize = 0;
    
    // find out how many audio devices there are, if any
    AudioObjectPropertyAddress theAddress = { kAudioHardwarePropertyDevices,
                                              kAudioObjectPropertyScopeGlobal,
                                              kAudioObjectPropertyElementMaster };
    
 
    err = AudioObjectGetPropertyDataSize(kAudioObjectSystemObject, &theAddress, 0, NULL, &theDataSize);
    if ( err != noErr ) return err;
   
    // calculate the number of device available
    *devicesAvailable = theDataSize / (UInt32)sizeof(AudioObjectID);                        
    if ( *devicesAvailable < 1 ) {
        fprintf( stderr, "No devices\n" );
        return err;
    }
    
    // make space for the devices we are about to get
    if (*devices != NULL) free(*devices);
    *devices = (Ptr)malloc(theDataSize);
    memset( *devices, 0, theDataSize );
    
    err = AudioObjectGetPropertyData(kAudioObjectSystemObject, &theAddress, 0, NULL, &theDataSize, (void *)*devices);
 
    return err;
}
 
OSStatus AOPropertyListenerProc(AudioObjectID inObjectID, UInt32 inNumberAddresses, const AudioObjectPropertyAddress inAddresses[], void* inClientData)
{
    AppController *app = (AppController*)inClientData;
    
    for (UInt32 x=0; x<inNumberAddresses; x++) {
    
        switch (inAddresses[x].mSelector)
        {
    /*
     * These are the other types of notifications we might receive, however, they are beyond
     * the scope of this sample and we ignore them.
     *
            case kAudioHardwarePropertyDefaultInputDevice:
                fprintf(stderr, "AOPropertyListenerProc: default input device changed\n");
            break;
                
            case kAudioHardwarePropertyDefaultOutputDevice:
                fprintf(stderr, "AOPropertyListenerProc: default output device changed\n");
            break;
                
            case kAudioHardwarePropertyDefaultSystemOutputDevice:
                fprintf(stderr, "AOPropertyListenerProc: default system output device changed\n");
            break;
    */
            case kAudioHardwarePropertyDevices:
            {
                fprintf(stderr, "AOPropertyListenerProc: kAudioHardwarePropertyDevices\n");
                [app performSelectorOnMainThread:@selector(updateDeviceList) withObject:nil waitUntilDone:NO];
            }
            break;
                
            default:
                fprintf(stderr, "AOPropertyListenerProc: unknown message\n");
            break;
        }
    }
    
    return noErr;
}
 
@implementation AppController
 
-(void) awakeFromNib
{
    // create empty array to hold device info
    deviceArray = [[NSMutableArray alloc] init];
    if(!deviceArray)
        return;
 
    // generate initial device list
    [self updateDeviceList];
    
    // install kAudioHardwarePropertyDevices notification listener
    AudioObjectPropertyAddress theAddress = { kAudioHardwarePropertyDevices,
                                              kAudioObjectPropertyScopeGlobal,
                                              kAudioObjectPropertyElementMaster };
    
    AudioObjectAddPropertyListener(kAudioObjectSystemObject, &theAddress, AOPropertyListenerProc, self);
}
 
- (void)windowWillClose:(NSNotification *)notification
{
    // remove kAudioHardwarePropertyDevices notification listener
    AudioObjectPropertyAddress theAddress = { kAudioHardwarePropertyDevices,
                                              kAudioObjectPropertyScopeGlobal,
                                              kAudioObjectPropertyElementMaster };
    
    AudioObjectRemovePropertyListener(kAudioObjectSystemObject, &theAddress, AOPropertyListenerProc, self);
}
 
- (void)updateDeviceList
{
    OSStatus    err = noErr;
    UInt32      ioSize = 0;
    UInt32      theNumberInputChannels  = 0;
    UInt32      theNumberOutputChannels = 0;
    UInt32      theIndex = 0;
    UInt16      devicesAvailable = 0;
    UInt16      loopCount = 0;
    
    AudioBufferList *theBufferList = NULL;
    CFNumberRef     tempNumberRef = NULL;
    CFStringRef     tempStringRef = NULL;
    
    // clear out any current entries in device array
    [deviceArray removeAllObjects];
    
    // fetch a pointer to the list of available devices
    if(GetAudioDevices((Ptr*)&devices, &devicesAvailable) != noErr)
        return;
    
    // iterate over each device gathering information
    for(loopCount = 0; loopCount < devicesAvailable; loopCount++)
    {
        CFMutableDictionaryRef theDict = NULL;
        UInt16 deviceID = devices[loopCount];
        
        // create dictionary to hold device info
        theDict = CFDictionaryCreateMutable(kCFAllocatorDefault, 0, &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks);
        if ( theDict == NULL )
        {
            fprintf(stderr, "Dictionary Creation Failed\n" );
            return;
        }
 
        // save device id
        tempNumberRef = CFNumberCreate(kCFAllocatorDefault,kCFNumberShortType,&deviceID);
        if(tempNumberRef)
        {
            CFDictionarySetValue(theDict, CFSTR("id"), tempNumberRef);
            CFRelease(tempNumberRef);
        }
        
        // get device name
        AudioObjectPropertyAddress theAddress = { kAudioObjectPropertyName,
                                                  kAudioObjectPropertyScopeGlobal,
                                                  kAudioObjectPropertyElementMaster };
                                                  
        ioSize = sizeof(CFStringRef);
        err = AudioObjectGetPropertyData(devices[loopCount], &theAddress, 0, NULL, &ioSize, &tempStringRef);
        if(tempStringRef && noErr == err)
        {
            CFDictionarySetValue(theDict, CFSTR("name"), tempStringRef);
            CFRelease(tempStringRef);
        }
        
        // get number of input channels
        ioSize = 0;
        theNumberInputChannels = 0;
        
        theAddress.mSelector = kAudioDevicePropertyStreamConfiguration;
        theAddress.mScope =  kAudioObjectPropertyScopeInput;
        theAddress.mElement = 0;
        
        err = AudioObjectGetPropertyDataSize(devices[loopCount], &theAddress, 0, NULL, &ioSize);
        if((err == noErr) && (ioSize != 0))
        {
            theBufferList = (AudioBufferList*)malloc(ioSize);
            if(theBufferList != NULL)
            {
                // get the input stream configuration
                err = AudioObjectGetPropertyData(devices[loopCount], &theAddress, 0, NULL, &ioSize, theBufferList);
                if(err == noErr)
                {
                    // count the total number of input channels in the stream
                    for(theIndex = 0; theIndex < theBufferList->mNumberBuffers; ++theIndex)
                            theNumberInputChannels += theBufferList->mBuffers[theIndex].mNumberChannels;
                }
                free(theBufferList);
                tempNumberRef = CFNumberCreate(kCFAllocatorDefault,kCFNumberSInt32Type,&theNumberInputChannels);
                if(tempNumberRef) {
                    CFDictionarySetValue(theDict, CFSTR("ich"), tempNumberRef);
                    CFRelease(tempNumberRef);
                }
            }
        }
        
        // get number of output channels
        ioSize = 0;
        theNumberOutputChannels = 0;
        
        theAddress.mScope = kAudioObjectPropertyScopeOutput;
        
        err = AudioObjectGetPropertyDataSize(devices[loopCount], &theAddress, 0, NULL, &ioSize);
        if((err == noErr) && (ioSize != 0))
        {
            theBufferList = (AudioBufferList*)malloc(ioSize);
            if(theBufferList != NULL)
            {
                // get the input stream configuration
                err = AudioObjectGetPropertyData(devices[loopCount], &theAddress, 0, NULL, &ioSize, theBufferList);
                if(err == noErr)
                {
                    // count the total number of output channels in the stream
                    for(theIndex = 0; theIndex < theBufferList->mNumberBuffers; ++theIndex)
                            theNumberOutputChannels += theBufferList->mBuffers[theIndex].mNumberChannels;
                }
                free(theBufferList);
                tempNumberRef = CFNumberCreate(kCFAllocatorDefault,kCFNumberSInt32Type,&theNumberOutputChannels);
                if(tempNumberRef) {
                    CFDictionarySetValue(theDict, CFSTR("och"), tempNumberRef);
                    CFRelease(tempNumberRef);
                }
            }
        }
        
        [deviceArray addObject:(NSDictionary*)theDict];
        CFRelease(theDict);
    }
    
    [myTable reloadData];
}
 
- (NSUInteger)numberOfRowsInTableView:(NSTableView *)aTableView
{
    return [deviceArray count];
}
 
- (id)tableView:(NSTableView *)aTableView
      objectValueForTableColumn:(NSTableColumn *)aTableColumn
      row:(int)rowIndex
{
    NSDictionary *deviceDict = NULL;
    
    deviceDict = [deviceArray objectAtIndex:rowIndex];
    return [deviceDict objectForKey:[aTableColumn identifier]];
}
 
@end