Use existing track names from midi file instead of overwriting them w…

…ith "InitializedTrack" (#2903)

* - Read track names from midi file instead of naming them "InitializedTrack"
- Do not set a track name for tracks not named in midi file

* Remove double space in comment

* Use parameter position in function addMetaEvent and make it optional

* Allow overwriting track name from meta event and replace existing meta event.
Only use existing track name from meta event, if the name parameter is an empty string

* Fix whitespace and statement position violations reported by hound bot

---------

Co-authored-by: Matthias Bauer <[email protected]>

Sources/AudioKit/Sequencing/Apple Sequencer/AppleSequencer.swift

@@ -668,7 +668,7 @@ open class AppleSequencer: NSObject {
  MusicSequenceGetIndTrack(existingSequence, UInt32(i), &musicTrack)
  }
  if let existingMusicTrack = musicTrack {
- tracks.append(MusicTrackManager(musicTrack: existingMusicTrack, name: "InitializedTrack"))
+ tracks.append(MusicTrackManager(musicTrack: existingMusicTrack, name: ""))
  }
  }
 

Sources/AudioKit/Sequencing/Apple Sequencer/MusicTrack.swift

@@ -81,25 +81,47 @@ open class MusicTrackManager {
  ///
  /// - parameter musicTrack: An Apple Music Track
  /// - parameter name: Name for the track
+ /// - if name is an empty string, the name is read from track name meta event.
+ /// - if name is not empty, that name is used and a track name meta event is added or replaced.
  ///
  public init(musicTrack: MusicTrack, name: String = "Unnamed") {
  self.name = name
  internalMusicTrack = musicTrack
  trackPointer = UnsafeMutablePointer(musicTrack)
 
- let data = [MIDIByte](name.utf8)
-
- let metaEventPtr = MIDIMetaEvent.allocate(metaEventType: 3, data: data)
- defer { metaEventPtr.deallocate() }
-
- let result = MusicTrackNewMetaEvent(musicTrack, MusicTimeStamp(0), metaEventPtr)
- if result != 0 {
- Log("Unable to name Track")
+ if name == "" {
+ // Use track name from meta event (or empty name if no meta event found)
+ self.name = tryReadTrackNameFromMetaEvent() ?? ""
+ } else {
+ // Clear track name meta event if exists
+ clearMetaEvent(3)
+ // Add meta event with new track name
+ let data = [MIDIByte](name.utf8)
+ addMetaEvent(metaEventType: 3, data: data)
  }
 
  initSequence()
  }
 
+ /// Try to read existing track name from meta event
+ ///
+ /// - returns: the found track name or nil
+ ///
+ func tryReadTrackNameFromMetaEvent() -> String? {
+ var trackName: String?
+
+ eventData?.forEach({ event in
+ if event.type == kMusicEventType_Meta {
+ let metaEventPointer = UnsafeMIDIMetaEventPointer(event.data)
+ let metaEvent = metaEventPointer!.event.pointee
+ if metaEvent.metaEventType == 0x03 {
+ trackName = String(decoding: metaEventPointer!.payload, as: UTF8.self)
+ }
+ }
+ })
+ return trackName
+ }
+
  /// Initialize with a music track and the NoteEventSequence
  ///
  /// - parameter musicTrack: An Apple Music Track
@@ -360,6 +382,48 @@ open class MusicTrackManager {
  DisposeMusicEventIterator(iterator)
  }
 
+ /// Clear a specific meta event
+ public func clearMetaEvent(_ metaEventType: MIDIByte) {
+ guard let track = internalMusicTrack else {
+ Log("internalMusicTrack does not exist")
+ return
+ }
+ var tempIterator: MusicEventIterator?
+ NewMusicEventIterator(track, &tempIterator)
+ guard let iterator = tempIterator else {
+ Log("Unable to create iterator in clearNote")
+ return
+ }
+ var eventTime = MusicTimeStamp(0)
+ var eventType = MusicEventType()
+ var eventData: UnsafeRawPointer?
+ var eventDataSize: UInt32 = 0
+ var hasNextEvent: DarwinBoolean = false
+ var isReadyForNextEvent: Bool
+
+ MusicEventIteratorHasCurrentEvent(iterator, &hasNextEvent)
+ while hasNextEvent.boolValue {
+ isReadyForNextEvent = true
+ MusicEventIteratorGetEventInfo(iterator,
+ &eventTime,
+ &eventType,
+ &eventData,
+ &eventDataSize)
+ if eventType == kMusicEventType_Meta {
+ if let convertedData = eventData?.load(as: MIDIMetaEvent.self) {
+ if convertedData.metaEventType == metaEventType {
+ MusicEventIteratorDeleteEvent(iterator)
+ isReadyForNextEvent = false
+ }
+ }
+ }
+
+ if isReadyForNextEvent { MusicEventIteratorNextEvent(iterator) }
+ MusicEventIteratorHasCurrentEvent(iterator, &hasNextEvent)
+ }
+ DisposeMusicEventIterator(iterator)
+ }
+
  /// Determine if the sequence is empty
  open var isEmpty: Bool {
  guard let track = internalMusicTrack else {
@@ -559,6 +623,28 @@ open class MusicTrackManager {
  }
  }
 
+ /// Add MetaEvent to sequence
+ ///
+ /// - Parameters:
+ /// - data: The MIDI data byte array - standard bytes containing the length of the data are added automatically
+ /// - position: Where in the sequence to start the note (expressed in beats)
+ ///
+ public func addMetaEvent(metaEventType: MIDIByte,
+ data: [MIDIByte],
+ position: Duration = Duration(beats: 0)) {
+ guard let track = internalMusicTrack else {
+ Log("internalMusicTrack does not exist")
+ return
+ }
+ let metaEventPtr = MIDIMetaEvent.allocate(metaEventType: metaEventType, data: data)
+ defer { metaEventPtr.deallocate() }
+
+ let result = MusicTrackNewMetaEvent(track, position.musicTimeStamp, metaEventPtr)
+ if result != 0 {
+ Log("Unable to write meta event")
+ }
+ }
+
  /// Add Pitch Bend change to sequence
  ///
  /// - Parameters: