An Objective-C midi event class that is part of a sequencer engine that I wrote for iOS before CoreMidi. The class saves actual universal midi event packages but allows initializing events with simple Int parameters. The sequencer engine is a circular buffer that stores events played at the eventTimeInTicks. CoreMidi was first available in iOS 4…

MidiEvent.h

//
//  MidiEvent.h - Part of a music sequencer audio engine framework written by Andre Todman.
//  Used in several audio applications in the App Store (2007-2010).
//  Created by Andre Todman on 8/8/09.
//
// 	Copyright 2009 Pubfuse Inc. All rights reserved.

/* ******************************************************************************************* *\
*  A midi event class that is part of a sequencer engine that I wrote for iOS before CoreMidi.  *
*  The class saves actual universal midi event packages but allows initializing events with     *
*  simple Int parameters. See: https://en.wikipedia.org/wiki/MIDI_1.0                           *
*  The sequencer engine is a circular buffer that stores events played at the eventTimeInTicks. *
*  CoreMidi was first available in iOS 4.1 around 2010.                                         *
\* ******************************************************************************************* */

// Struct to store modes for offset event times.
// Each mode has different strengths that will trigger events with a different swing
// This allow a more natural feel during playback
struct swingQuantizeTime {
	
	 float closest_for_setting_0;
	 float closest_for_setting_1;
	 float closest_for_setting_2;
	 float closest_for_setting_3;
	 float closest_for_setting_4;
	 float closest_for_setting_5;
	 float closest_for_setting_6;
	 float closest_for_setting_7;
	 float closest_for_setting_8;
	 float closest_for_setting_9;
 };

/// Class to store a Midi Event with properties that use midi event messages
@interface MidiEvent : NSObject   {
		
	struct	swingQuantizeTime  quantizedTime; 	// value to snap event time to
	
	NSNumber* on;								// On or off
	NSNumber* triggerPlay;						// Trigger midi play message
	NSNumber* triggerStop;  					// Trigger midi stop message
	NSNumber* didPlay;							// Save playback state each loop.
	NSNumber* midiVelocity;						// Volume for the event
	NSNumber* beatPosition_0First_15ForLast;	// Position of playback in simple 16/th beat mode
	NSNumber* timeExact0__to_late7;				// Offset event time randomly between abount to allow a natural feel
	NSNumber* midiBar;							// Bar in beats where the even is played
	NSNumber* midiNote; 						// The value of the midi note, for example 63 for middle C
	NSNumber* midiChan;		   					// Midi Channel of the event
	NSNumber* eventTimeInTicks;					// The event time in ticks per beat
}

//- Generated getters & setters
@property(nonatomic,retain)NSNumber* on;
@property(nonatomic,retain)NSNumber* triggerPlay;  
@property(nonatomic,retain)NSNumber* triggerStop;  
@property(nonatomic,retain)NSNumber* didPlay;  
@property(nonatomic,retain)NSNumber* midiVelocity;  
@property(nonatomic,retain)NSNumber* beatPosition_0First_15ForLast;  
@property(nonatomic,retain)NSNumber* timeExact0__to_late7;  
@property(nonatomic,retain)NSNumber* midiBar;  
@property(nonatomic,retain)NSNumber* midiNote;  
@property(nonatomic,retain)NSNumber* midiChan;		  
@property(nonatomic,retain)NSNumber* eventTimeInTicks;   
@property struct swingQuantizeTime  quantizedTime;

/// Creates a new MidiEvent and initializes it's position of playback, the bar, the note on off display, and the assigned pad number
/// @param beatColNumber Position of playback in simple 16/th beat
/// @param precisionRowNumber Int that stores the position of playback for the event
/// @param theBarNumber Int that stores the bar of playback time
/// @param onOffOther_123 Int that stores on (1), off (0) or other (Custom Midi Message) state.
/// @param padNum The pad number that binds to the midi event. When pressed, allows the sequencer to save the event
-(id) initWithBeatNumber_0__to_15:(int)beatColNumber precision_0_to_7:(int)precisionRowNumber  barNumber:(int)theBarNumber setOn1_off0__other2:(int)onOffOther_123 andPad:(int)padNum;

/// Returns the MidiEvent tickPerBeat as Float with swing time forin the current swing setting.
/// Changing during playback in the sequencer engine, you would hear a drummer play more relaxed, for example.
/// @param n Int Setting to use a for swing
-(float)getQuantizedTimeForSetting:(int)n;

/// Change  MidiEvent and  it's position of playback, the bar, the note on off display
/// @param beat Position of playback in simple 16/th beat
/// @param barNumber Int that stores the bar of playback time
/// @param timeExact Swing setting as in where 0 is exact playback time and 7 is late
-(void)setBeatPosition__0First_15ForLast:(int)beat andBar:(int)barNumber andTimeExact0__to_late7:(int)timeExact;

/// Sets note on/off
/// @param Set note on or off
-(void)setOn1_off0__other2:(int)n;

/// Get NoteOn,NoteOff or Other value
-(int)getOn1_off0__other2 ;

/// Set Quantization offset
/// @param n quantize number as Int
/// @param ev time in ticks of event
-(void)setQuantizeNumber:(int)n withTime:(float)ev;

/// Set bar in beat to play event
/// @param n Bar number to play the event at
-(void)setBar:(int)n;

/// Compare another event to see if it is equal
/// @param midi other event
-(BOOL)isEqual:(MidiEvent*)midi;

/// Copy another midi event
/// @param midi another midi event
-(void)copyEvent:(MidiEvent*)midi;
@end

MidiEvent.mm

//
//  MidiEvent.h - Part of a music sequencer audio engine framework written by Andre Todman.
//  Used in several audio applications in the App Store (2007-2010).
//  Created by Andre Todman on 8/8/09.
//
// 	Copyright 2009 Pubfuse Inc. All rights reserved.

/* ******************************************************************************************* *\
*  A midi event class that is part of a sequencer engine that I wrote for iOS before CoreMidi.  *
*  The class saves actual universal midi event packages but allows initializing events with     *
*  simple Int parameters. See: https://en.wikipedia.org/wiki/MIDI_1.0                           *
*  The sequencer engine is a circular buffer that stores events played at the eventTimeInTicks. *
*  CoreMidi was first available in iOS 4.1 around 2010.                                         *
\* ******************************************************************************************* */

#import "MidiEvent.h"

@implementation MidiEvent

@synthesize on;
@synthesize triggerPlay;
@synthesize triggerStop;
@synthesize didPlay;
@synthesize midiVelocity;
@synthesize beatPosition_0First_15ForLast;
@synthesize timeExact0__to_late7;
@synthesize midiBar;
@synthesize midiNote;
@synthesize midiChan;
@synthesize eventTimeInTicks;
@synthesize quantizedTime;


/// Initializes a midi event
-(id) init {
	if (self = [super init]) {
		
		on = [[[NSNumber alloc]init ]retain] ;  
		triggerPlay  = [[[NSNumber alloc]init ]retain] ; 
		triggerStop  = [[[NSNumber alloc]init ]retain] ; 
		didPlay   = [[[NSNumber alloc]init ]retain] ;   
		midiVelocity   = [[[NSNumber alloc]init ]retain] ;  		
		beatPosition_0First_15ForLast  = [[[NSNumber alloc]init ]retain] ; 
		timeExact0__to_late7  = [[[NSNumber alloc]init ]retain] ;   
		midiBar  = [[[NSNumber alloc]init ]retain] ;  
		midiNote  = [[NSNumber alloc]init ] ;   
		midiChan  = [[[NSNumber alloc]init ]retain] ;		 
		eventTimeInTicks  = [[[NSNumber alloc]init ]retain] ;  
	}
	
	return self;
}

/// Creates a new MidiEvent and initializes it's position of playback, the bar, the note on off display, and the assigned pad number
/// @param beatColNumber Position of playback in simple 16/th beat
/// @param precisionRowNumber Int that stores the position of playback for the event
/// @param theBarNumber Int that stores the bar of playback time
/// @param onOffOther_123 Int that stores on (1), off (0) or other (Custom Midi Message) state.
/// @param padNum The pad number that binds to the midi event. When pressed, allows the sequencer to save the event
-(id) initWithBeatNumber_0__to_15:(int)beatColNumber precision_0_to_7:(int)precisionRowNumber  barNumber:(int)theBarNumber setOn1_off0__other2:(int)onOffOther_123  andPad:(int)padNum{
	
	if (self = [super init]) {
		
		[self setOn:[ NSNumber numberWithInt:-1]];
		[self setTriggerPlay:[ NSNumber numberWithBool:NO]];
		[self setTriggerStop:[ NSNumber numberWithBool:NO]];
		[self setDidPlay:[ NSNumber numberWithBool:NO]];
		[self setMidiVelocity:[ NSNumber numberWithFloat:1.0f]];
		[self setBeatPosition_0First_15ForLast:[ NSNumber numberWithInt:0]];
		[self setTimeExact0__to_late7:[ NSNumber numberWithInt:0]];
		[self setMidiBar:[ NSNumber numberWithInt:theBarNumber]];
		[self setMidiNote:[ NSNumber numberWithInt:padNum]];
		[self setMidiChan:[ NSNumber numberWithInt:0]];
		[self setEventTimeInTicks:[ NSNumber numberWithInt:0]];
		
		if(onOffOther_123 == 1){
			
			[self setOn:[ NSNumber numberWithBool:YES]];
			[self setTriggerPlay:[ NSNumber numberWithBool:YES]];
			[self setTriggerStop:[ NSNumber numberWithBool:NO]];
		}
		else if(onOffOther_123 == 0){
			
			[self setOn:[ NSNumber numberWithBool:YES]];
			[self setTriggerPlay:[ NSNumber numberWithBool:NO]];
			[self setTriggerStop:[ NSNumber numberWithBool:YES]];
		}
		else if(onOffOther_123 == 2){
			
			[self setOn:[ NSNumber numberWithBool:YES]];
			[self setTriggerPlay:[ NSNumber numberWithBool:NO]];
			[self setTriggerStop:[ NSNumber numberWithBool:NO]];
		}
	}
	
	return self;
}



/// Allows Initializing a saved object automatically when the app is loaded
/// @param coder the save encoded object to load
-(id) initWithCoder:(NSCoder *)coder {
	
	[super init];
	
	on = [[coder decodeObjectForKey:@"on"] retain];
	triggerPlay = [[coder decodeObjectForKey:@"triggerPlay"] retain];
	triggerStop = [[coder decodeObjectForKey:@"triggerStop"] retain];
	didPlay = [[coder decodeObjectForKey:@"didPlay"] retain];
	midiVelocity = [[coder decodeObjectForKey:@"midiVelocity"] retain];
	beatPosition_0First_15ForLast= [[coder decodeObjectForKey:@"beatPosition_0First_15ForLast"] retain];
	timeExact0__to_late7= [[coder decodeObjectForKey:@"timeExact0__to_late7"] retain];
	midiBar= [[coder decodeObjectForKey:@"midiBar"] retain];
	midiNote= [[coder decodeObjectForKey:@"midiNote"] retain];
	midiChan= [[coder decodeObjectForKey:@"midiChan"] retain];
	eventTimeInTicks= [[coder decodeObjectForKey:@"eventTimeInTicks"] retain];
	
	return self;
}


/// Saves the current object and it's values
/// @param encoder encoded object ref
-(void) encodeWithCoder:(NSCoder *)encoder {
	
	[encoder   encodeObject:on forKey:@"on"];
	[encoder   encodeObject:triggerPlay forKey:@"triggerPlay"];
	[encoder   encodeObject:triggerStop forKey:@"triggerStop"];
	[encoder   encodeObject:didPlay forKey:@"didPlay"];
	[encoder  encodeObject:midiVelocity forKey:@"midiVelocity"];
	[encoder  encodeObject:beatPosition_0First_15ForLast forKey:@"beatPosition_0First_15ForLast"];
	[encoder  encodeObject:timeExact0__to_late7 forKey:@"timeExact0__to_late7"];
	[encoder  encodeObject:midiBar forKey:@"midiBar"];
	[encoder  encodeObject:midiNote forKey:@"midiNote"];
	[encoder  encodeObject:midiChan forKey:@"midiChan"];
	[encoder  encodeObject:eventTimeInTicks forKey:@"eventTimeInTicks"];
}


/// Sets the midi note
/// @param n Value of the midi key, 63 is middle C
-(void)setNote:(int)n{
	[self setMidiNote:[ NSNumber numberWithInt:n]];
}


/// Sets the midi channel
/// @param n New midi channel to use
-(void)setChan:(int)n{
	[self setMidiChan:[ NSNumber numberWithInt:n]];
}


/// Sets Velocity to of the note
/// @param n Velocity amount
-(void)setVelocity:(float)n{
	
	[self setMidiVelocity:[ NSNumber numberWithFloat:n]];
}

/// Returns the MidiEvent tickPerBeat as Float with swing time forin the current swing setting.
/// Changing during playback in the sequencer engine, you would hear a drummer play more relaxed, for example.
/// @param n Int Setting to use a for swing
-(float)getQuantizedTimeForSetting:(int)n{
	
	switch (n) {
		case 0:
			return quantizedTime.closest_for_setting_0;
			break;
		case 1:
			return quantizedTime.closest_for_setting_1;
			break;
		case 2:
			return quantizedTime.closest_for_setting_2;
			break;
		case 3:
			return quantizedTime.closest_for_setting_3;
			break;
		case 4:
			return quantizedTime.closest_for_setting_4;
			break;
		case 5:
			return quantizedTime.closest_for_setting_5;
			break;
		case 6:
			return quantizedTime.closest_for_setting_6;
			break;
		case 7:
			return quantizedTime.closest_for_setting_7;
			break;
		case 8:
			return quantizedTime.closest_for_setting_8;
			break;
		case 9:
			return quantizedTime.closest_for_setting_9;
			break;
		default:
			return -100;
			break;
	}
}

/// Change  MidiEvent and  it's position of playback, the bar, the note on off display
/// @param beat Position of playback in simple 16/th beat
/// @param barNumber Int that stores the bar of playback time
/// @param timeExact Swing setting as in where 0 is exact playback time and 7 is late
-(void)setBeatPosition__0First_15ForLast:(int)beat andBar:(int)barNumber andTimeExact0__to_late7:(int)timeExact{
	
	[self setBeatPosition_0First_15ForLast:[ NSNumber numberWithInt:beat]];
	[self setTimeExact0__to_late7:[ NSNumber numberWithInt:timeExact]];
	[self setBar: barNumber ];
}

/// Set bar in beat to play event
/// @param n Bar number to play the event at
-(void)setBar:(int)n{
	
 	[self setMidiBar:[ NSNumber numberWithInt:n]];
}

/// Set Quantization offset
/// @param n quantize number as Int
/// @param ev time in ticks of event
-(void) setQuantizeNumber:(int)n withTime:(float)ev{
	
	switch (n) {
		case 0:
			quantizedTime.closest_for_setting_0 = ev;
			break;
		case 1:
			 quantizedTime.closest_for_setting_1= ev;
			break;
		case 2:
			 quantizedTime.closest_for_setting_2= ev;
			break;
		case 3:
			  quantizedTime.closest_for_setting_3= ev;
			break;
		case 4:
			  quantizedTime.closest_for_setting_4= ev;
			break;
		case 5:
			  quantizedTime.closest_for_setting_5= ev;
			break;
		case 6:
			  quantizedTime.closest_for_setting_6= ev;
			break;
		case 7:
			  quantizedTime.closest_for_setting_7= ev;
			break;
		case 8:
			  quantizedTime.closest_for_setting_8= ev;
			break;
		case 9:
			  quantizedTime.closest_for_setting_9= ev;
			break;
		
	}
}


/// Sets note on
-(void)setNoteOn{
	
	[self setOn:[ NSNumber numberWithBool:YES]];
}


/// Sets note off
-(void)setNoteOff{
	
	[self setOn:[ NSNumber numberWithBool:YES]];
}


/// Triggers a stop event when played if this is enabled
/// @param n set if enabled
-(void)shouldTriggerStop:(BOOL)n{
	[self setOn:[ NSNumber numberWithBool:YES]];
	[self setTriggerStop:[ NSNumber numberWithBool:n]];
}
 

/// Deallocate objects
-(void)dealloc{
	
	[ on release]; 
	[ triggerPlay release];  
	[ triggerStop release];  
	[ didPlay release];  
	[ midiVelocity release]; 
	[ beatPosition_0First_15ForLast release];  
	[ timeExact0__to_late7 release];  
	[ midiBar release];   
	[ midiNote release];  
	[ midiChan release];
	[ eventTimeInTicks release];
	
	[super dealloc];	
}

/// Sets note on/off
/// @param Set note on or off
-(void)setOn1_off0__other2:(int)n{
	
	if(n == 1){

		[self setOn:[ NSNumber numberWithBool:YES]];
		[self setTriggerPlay:[ NSNumber numberWithBool:YES]];
		[self setTriggerStop:[ NSNumber numberWithBool:NO]];

	}
	else if(n == 0){

		[self setOn:[ NSNumber numberWithBool:YES]];
		[self setTriggerPlay:[ NSNumber numberWithBool:NO]];
		[self setTriggerStop:[ NSNumber numberWithBool:YES]];

	}
	else if(n == 2){

		[self setOn:[ NSNumber numberWithBool:YES]];
		[self setTriggerPlay:[ NSNumber numberWithBool:NO]];
		[self setTriggerStop:[ NSNumber numberWithBool:NO]];
	}
}

/// Get NoteOn,NoteOff or Other value
-(int)getOn1_off0__other2{
	int result;
	
	if(triggerPlay.boolValue == YES && triggerStop.boolValue ==NO){
		result =1	;
	}
	else if(triggerPlay.boolValue == NO && triggerStop.boolValue ==YES){
		result =0;
	}
	else if(triggerPlay.boolValue == NO && triggerStop.boolValue ==NO){
		result  =2;
	}
	
	return result;
}

/// Compare another event to see if it is equal
/// @param midi other event
-(BOOL)isEqual:(MidiEvent*)midi{
	
	BOOL result = NO;
	
	if(
	   on == [midi on] &&
	   triggerPlay  == [midi triggerPlay] &&
	   triggerStop  == [midi triggerStop] &&
	   didPlay   == [midi didPlay] &&
	   midiVelocity   == [midi midiVelocity] &&
	   beatPosition_0First_15ForLast  == [midi beatPosition_0First_15ForLast] &&
	   timeExact0__to_late7  == [midi timeExact0__to_late7] &&
	   midiBar  == [midi midiBar] &&
	   midiNote  == [midi midiNote] &&
	   midiChan  == [midi midiChan] &&
	   eventTimeInTicks  == [midi eventTimeInTicks]
	)result = YES;
	
	return result;
}

/// Copy another midi event
/// @param midi another midi event
-(void)copyEvent:(MidiEvent*)midi{
	 
	on = [NSNumber numberWithBool:[midi on].boolValue]; 
	triggerPlay  = [NSNumber numberWithBool:[midi triggerPlay].boolValue]; 
	triggerStop  = [NSNumber numberWithBool:[midi triggerStop].boolValue]; 
	didPlay   = [NSNumber numberWithBool:YES] ;
	
	midiVelocity   = [ NSNumber numberWithFloat: [midi midiVelocity].floatValue] ;  		
	beatPosition_0First_15ForLast  =[NSNumber numberWithInt: [midi beatPosition_0First_15ForLast].intValue] ; 
	timeExact0__to_late7  = [NSNumber numberWithInt: [midi timeExact0__to_late7].intValue] ;  
	midiBar  = [NSNumber numberWithInt: [midi midiBar] .intValue];
	midiNote  = [NSNumber numberWithInt: [midi midiNote].intValue] ;  
	midiChan  = [NSNumber numberWithInt: [midi midiChan].intValue];	 
	eventTimeInTicks  =[NSNumber numberWithInt:  [midi eventTimeInTicks].intValue ] ; 
	quantizedTime = [midi	quantizedTime];
 }
@end