macosx: set volume

#import <AudioToolbox/AudioServices.h>

// getting system volume

+(float)volume 
{
	Float32			outputVolume;
	
	UInt32 propertySize = 0;
	OSStatus status = noErr;
	AudioObjectPropertyAddress propertyAOPA;
	propertyAOPA.mElement = kAudioObjectPropertyElementMaster;
	propertyAOPA.mSelector = kAudioHardwareServiceDeviceProperty_VirtualMasterVolume;
	propertyAOPA.mScope = kAudioDevicePropertyScopeOutput;
	
	AudioDeviceID outputDeviceID = [KNVolumeControl defaultOutputDeviceID];
		
	if (outputDeviceID == kAudioObjectUnknown)
	{
		NSLog(@"Unknown device");
		return 0.0;
	}
	
	if (!AudioHardwareServiceHasProperty(outputDeviceID, &propertyAOPA))
	{
		NSLog(@"No volume returned for device 0x%0x", outputDeviceID);
		return 0.0;
	}
	
	propertySize = sizeof(Float32);
	
	status = AudioHardwareServiceGetPropertyData(outputDeviceID, &propertyAOPA, 0, NULL, &propertySize, &outputVolume);
	
	if (status)
	{
		NSLog(@"No volume returned for device 0x%0x", outputDeviceID);
		return 0.0;
	}
	
	if (outputVolume < 0.0 || outputVolume > 1.0) return 0.0;
	
	return outputVolume;
}

// setting system volume - mutes if under threshhold 
+(void)setVolume:(Float32)newVolume
{
if (newVolume < 0.0 || newVolume > 1.0)
	{
		NSLog("Requested volume out of range (%.2f)", newVolume);
		return;
		
	}

	// get output device device
	UInt32 propertySize = 0;
	OSStatus status = noErr;
	AudioObjectPropertyAddress propertyAOPA;
	propertyAOPA.mElement = kAudioObjectPropertyElementMaster;
	propertyAOPA.mScope = kAudioDevicePropertyScopeOutput;
	
	if (newVolume < 0.001)
	{
		NSLog("Requested mute");
		propertyAOPA.mSelector = kAudioDevicePropertyMute;

	}
	else
	{
		NSLog("Requested volume %.2f", newVolume);
		propertyAOPA.mSelector = kAudioHardwareServiceDeviceProperty_VirtualMasterVolume;
	}
	
	AudioDeviceID outputDeviceID = [KNVolumeControl defaultOutputDeviceID];
	
	if (outputDeviceID == kAudioObjectUnknown)
	{
		NSLog(@"Unknown device");
		return;
	}
	
	if (!AudioHardwareServiceHasProperty(outputDeviceID, &propertyAOPA))
	{
		NSLog(@"Device 0x%0x does not support volume control", outputDeviceID);
		return;
	}
	
	Boolean canSetVolume = NO;
	
	status = AudioHardwareServiceIsPropertySettable(outputDeviceID, &propertyAOPA, &canSetVolume);
	
	if (status || canSetVolume == NO)
	{
		NSLog(@"Device 0x%0x does not support volume control", outputDeviceID);
		return;
	}
	
	if (propertyAOPA.mSelector == kAudioDevicePropertyMute)
	{
		propertySize = sizeof(UInt32);
		UInt32 mute = 1;
		status = AudioHardwareServiceSetPropertyData(outputDeviceID, &propertyAOPA, 0, NULL, propertySize, &mute);		
	}
	else
	{
		propertySize = sizeof(Float32);
		
		status = AudioHardwareServiceSetPropertyData(outputDeviceID, &propertyAOPA, 0, NULL, propertySize, &newVolume);	
		
		if (status)
		{
			NSLog(@"Unable to set volume for device 0x%0x", outputDeviceID);
		}
		
		// make sure we're not muted
		propertyAOPA.mSelector = kAudioDevicePropertyMute;
		propertySize = sizeof(UInt32);
		UInt32 mute = 0;
		
		if (!AudioHardwareServiceHasProperty(outputDeviceID, &propertyAOPA))
		{
			NSLog(@"Device 0x%0x does not support muting", outputDeviceID);
			return;
		}
		
		Boolean canSetMute = NO;
		
		status = AudioHardwareServiceIsPropertySettable(outputDeviceID, &propertyAOPA, &canSetMute);
		
		if (status || !canSetMute)
		{
			NSLog(@"Device 0x%0x does not support muting", outputDeviceID);
			return;
		}
		
		status = AudioHardwareServiceSetPropertyData(outputDeviceID, &propertyAOPA, 0, NULL, propertySize, &mute);
	}
		
	if (status)
	{
		NSLog(@"Unable to set volume for device 0x%0x", outputDeviceID);
	}

}

+(AudioDeviceID)defaultOutputDeviceID
{
	AudioDeviceID	outputDeviceID = kAudioObjectUnknown;
	
	// get output device device
	UInt32 propertySize = 0;
	OSStatus status = noErr;
	AudioObjectPropertyAddress propertyAOPA;
	propertyAOPA.mScope = kAudioObjectPropertyScopeGlobal;
	propertyAOPA.mElement = kAudioObjectPropertyElementMaster;
	propertyAOPA.mSelector = kAudioHardwarePropertyDefaultOutputDevice;
	
	if (!AudioHardwareServiceHasProperty(kAudioObjectSystemObject, &propertyAOPA))
	{
		NSLog(@"Cannot find default output device!");
		return outputDeviceID;
	}
	
	propertySize = sizeof(AudioDeviceID);
	
	status = AudioHardwareServiceGetPropertyData(kAudioObjectSystemObject, &propertyAOPA, 0, NULL, &propertySize, &outputDeviceID);
	
	if(status) 
	{
		NSLog(@"Cannot find default output device!");
	}
	return outputDeviceID;
}