Bumps version

Exposes AudioEngine’s mainMixerNode
Added missing documentation

AudioExample/AudioExample/Controllers/PlayerViewController.swift

@@ -55,7 +55,7 @@ class PlayerViewController: UIViewController {
         tableView.translatesAutoresizingMaskIntoConstraints = false
         tableView.delegate = self
         tableView.dataSource = self
-        tableView.register(UITableViewCell.self, forCellReuseIdentifier: "PlaylistCell")
+        tableView.register(PlaylistTableViewCell.self, forCellReuseIdentifier: "PlaylistCell")
 
         let controlsController = controlsProvider()
         playerControlsController = controlsController
@@ -120,6 +120,7 @@ extension PlayerViewController: UITableViewDataSource {
             return cell
         }
         cell.textLabel?.text = item.name
+        cell.detailTextLabel?.text = item.queues ? "Queue item" : nil
         update(status: item.status, of: cell)
         return cell
     }
@@ -147,3 +148,15 @@ extension PlayerViewController: UITableViewDelegate {
         viewModel.playItem(at: indexPath)
     }
 }
+
+
+final class PlaylistTableViewCell: UITableViewCell {
+    override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
+        super.init(style: .subtitle, reuseIdentifier: reuseIdentifier)
+    }
+
+    @available(*, unavailable)
+    required init?(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+}

AudioExample/AudioExample/Controllers/PlayerViewModel.swift

@@ -47,7 +47,7 @@ final class PlayerViewModel {
             print("malformed url error")
             return
         }
-        playlistItemsService.add(item: PlaylistItem(url: url, name: urlString, status: .stopped))
+        playlistItemsService.add(item: PlaylistItem(url: url, name: urlString, status: .stopped, queues: false))
         reloadContent?(.all)
     }
 
@@ -57,13 +57,20 @@ final class PlayerViewModel {
 
     func playItem(at indexPath: IndexPath) {
         guard let item = item(at: indexPath) else { return }
-        if let index = currentPlayingItemIndex {
-            playlistItemsService.setStatus(for: index, status: .stopped)
-            reloadContent?(.item(IndexPath(row: index, section: 0)))
-            currentPlayingItemIndex = nil
+        if item.queues {
+            playerService.queue(url: item.url)
+            if currentPlayingItemIndex == nil {
+                currentPlayingItemIndex = indexPath.row
+            }
+        } else {
+            if let index = currentPlayingItemIndex {
+                playlistItemsService.setStatus(for: index, status: .stopped)
+                reloadContent?(.item(IndexPath(row: index, section: 0)))
+                currentPlayingItemIndex = nil
+            }
+            playerService.play(url: item.url)
+            currentPlayingItemIndex = indexPath.row
         }
-        playerService.play(url: item.url)
-        currentPlayingItemIndex = indexPath.row
     }
 }
 

AudioExample/AudioExample/Services/AudioContent.swift

@@ -12,6 +12,7 @@ enum AudioContent: Int, CaseIterable {
     case offradio
     case enlefko
     case pepper966
+    case kosmos
     case radiox
     case khruangbin
     case piano
@@ -26,6 +27,8 @@ enum AudioContent: Int, CaseIterable {
             return "Enlefko (stream)"
         case .pepper966:
             return "Pepper 96.6 (stream)"
+        case .kosmos:
+            return "Kosmos 93.6 (stream)"
         case .radiox:
             return "Radio X (stream)"
         case .khruangbin:
@@ -47,6 +50,8 @@ enum AudioContent: Int, CaseIterable {
             return URL(string: "https://s3.yesstreaming.net:17062/stream")!
         case .pepper966:
             return URL(string: "https://ample-09.radiojar.com/pepper.m4a?1593699983=&rj-tok=AAABcw_1KyMAIViq2XpI098ZSQ&rj-ttl=5")!
+        case .kosmos:
+            return URL(string: "https://radiostreaming.ert.gr/ert-kosmos")!
         case .radiox:
             return URL(string: "https://media-ssl.musicradio.com/RadioXLondon")!
         case .khruangbin:

AudioExample/AudioExample/Services/AudioPlayerService.swift

@@ -56,6 +56,11 @@ final class AudioPlayerService {
         player.play(url: url)
     }
 
+    func queue(url: URL) {
+        activateAudioSession()
+        player.queue(url: url)
+    }
+
     func stop() {
         player.stop()
         deactivateAudioSession()

AudioExample/AudioExample/Services/PlaylistItemsService.swift

@@ -19,17 +19,20 @@ struct PlaylistItem: Equatable {
     let url: URL
     let name: String
     let status: Status
+    let queues: Bool
 
-    init(content: AudioContent) {
+    init(content: AudioContent, queues: Bool) {
         name = content.title
         url = content.streamUrl
         status = .stopped
+        self.queues = queues
     }
 
-    init(url: URL, name: String, status: Status) {
+    init(url: URL, name: String, status: Status, queues: Bool) {
         self.url = url
         self.name = name
         self.status = status
+        self.queues = queues
     }
 }
 
@@ -70,10 +73,14 @@ final class PlaylistItemsService {
         guard let item = item(at: index) else {
             return
         }
-        items[index] = PlaylistItem(url: item.url, name: item.name, status: status)
+        items[index] = PlaylistItem(url: item.url, name: item.name, status: status, queues: item.queues)
     }
 }
 
 func provideInitialPlaylistItems() -> [PlaylistItem] {
-    AudioContent.allCases.map(PlaylistItem.init(content:))
+    let allCases = AudioContent.allCases
+    let casesForQueueing: [AudioContent] = [.piano, .local, .khruangbin]
+    let allItems = allCases.map { PlaylistItem.init(content: $0 , queues: false) }
+    let casesForQueuingItems = casesForQueueing.map { PlaylistItem.init(content: $0 , queues: true) }
+    return allItems + casesForQueuingItems
 }

AudioStreaming.podspec

@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name = 'AudioStreaming'
-  s.version = '0.2.0'
+  s.version = '0.5.1'
   s.license = 'MIT'
   s.summary = 'An AudioPlayer/Streaming library for iOS written in Swift using AVAudioEngine.'
   s.homepage = 'https://github.com/dimitris-c/AudioStreaming'

AudioStreaming.xcodeproj/project.pbxproj

@@ -53,6 +53,8 @@
 		B5AEDBB824744153007D8101 /* AudioStreaming.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = B5AEDBAE24744153007D8101 /* AudioStreaming.framework */; };
 		B5AEDBBF24744153007D8101 /* AudioStreaming.h in Headers */ = {isa = PBXBuildFile; fileRef = B5AEDBB124744153007D8101 /* AudioStreaming.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		B5B3B7CC248647ED00656828 /* AudioPlayerState.swift in Sources */ = {isa = PBXBuildFile; fileRef = B5B3B7CB248647ED00656828 /* AudioPlayerState.swift */; };
+		B5D4A40925D9321400E1450C /* IcycastHeaderParser.swift in Sources */ = {isa = PBXBuildFile; fileRef = B5D4A40825D9321400E1450C /* IcycastHeaderParser.swift */; };
+		B5D4A41025D948EF00E1450C /* IcycastHeadersProcessor.swift in Sources */ = {isa = PBXBuildFile; fileRef = B5D4A40B25D9445600E1450C /* IcycastHeadersProcessor.swift */; };
 		B5D82E65255DD562009EDAA4 /* NetStatusService.swift in Sources */ = {isa = PBXBuildFile; fileRef = B5D82E64255DD562009EDAA4 /* NetStatusService.swift */; };
 		B5DB66E2255C2EAB00B8DF53 /* AudioEntryProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = B5DB66E1255C2EAB00B8DF53 /* AudioEntryProvider.swift */; };
 		B5E1DE2524B70B4200955BFB /* AudioPlayerConfiguration.swift in Sources */ = {isa = PBXBuildFile; fileRef = B5E1DE2424B70B4200955BFB /* AudioPlayerConfiguration.swift */; };
@@ -143,6 +145,8 @@
 		B5AEDBB724744153007D8101 /* AudioStreamingTests.xctest */ = {isa = PBXFileReference; explicitFileType = wrapper.cfbundle; includeInIndex = 0; path = AudioStreamingTests.xctest; sourceTree = BUILT_PRODUCTS_DIR; };
 		B5AEDBBE24744153007D8101 /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
 		B5B3B7CB248647ED00656828 /* AudioPlayerState.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AudioPlayerState.swift; sourceTree = "<group>"; };
+		B5D4A40825D9321400E1450C /* IcycastHeaderParser.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = IcycastHeaderParser.swift; sourceTree = "<group>"; };
+		B5D4A40B25D9445600E1450C /* IcycastHeadersProcessor.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = IcycastHeadersProcessor.swift; sourceTree = "<group>"; };
 		B5D82E64255DD562009EDAA4 /* NetStatusService.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NetStatusService.swift; sourceTree = "<group>"; };
 		B5DB66DA255C079C00B8DF53 /* AVFoundation.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = AVFoundation.framework; path = System/Library/Frameworks/AVFoundation.framework; sourceTree = SDKROOT; };
 		B5DB66E1255C2EAB00B8DF53 /* AudioEntryProvider.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AudioEntryProvider.swift; sourceTree = "<group>"; };
@@ -205,6 +209,7 @@
 				B55CEAB32485107C0001C498 /* Parser.swift */,
 				B55A736B247FCB420050C53D /* HTTPHeaderParser.swift */,
 				B55CE96D248058B60001C498 /* MetadataParser.swift */,
+				B5D4A40825D9321400E1450C /* IcycastHeaderParser.swift */,
 			);
 			path = Parsers;
 			sourceTree = "<group>";
@@ -257,6 +262,7 @@
 				B5667A8F2499018D00D93F85 /* AudioFileStreamProcessor.swift */,
 				B5667B3D249BC43000D93F85 /* AudioPlayerRenderProcessor.swift */,
 				B55CE97024810DE20001C498 /* MetadataStreamProcessor.swift */,
+				B5D4A40B25D9445600E1450C /* IcycastHeadersProcessor.swift */,
 			);
 			path = Processors;
 			sourceTree = "<group>";
@@ -594,6 +600,7 @@
 				B51B9F9A24DBE5BF00BDEAA2 /* AVAudioFormat+Convenience.swift in Sources */,
 				B51FE0C624890CCB00F2A4D2 /* PlayerQueueEntries.swift in Sources */,
 				B5EF9557247E9439003E8FF8 /* AudioStreamSource.swift in Sources */,
+				B5D4A40925D9321400E1450C /* IcycastHeaderParser.swift in Sources */,
 				B59DF1A32493E90C0043C498 /* AudioFileStream+Helpers.swift in Sources */,
 				B54D876D2490E4A000C361A0 /* UnitDescriptions.swift in Sources */,
 				B514657F248E3884005C03F7 /* DispatchTimerSource.swift in Sources */,
@@ -604,6 +611,7 @@
 				B5EF955B247EBCB3003E8FF8 /* AudioFileType.swift in Sources */,
 				B592E1252545FF9A008866FB /* BiMap.swift in Sources */,
 				B5DB66E2255C2EAB00B8DF53 /* AudioEntryProvider.swift in Sources */,
+				B5D4A41025D948EF00E1450C /* IcycastHeadersProcessor.swift in Sources */,
 				B5667A902499018D00D93F85 /* AudioFileStreamProcessor.swift in Sources */,
 				B59D0B6F255C904900D6CCE5 /* FileAudioSource.swift in Sources */,
 				B5EF9555247E9393003E8FF8 /* AudioEntry.swift in Sources */,
@@ -786,6 +794,7 @@
 			buildSettings = {
 				CLANG_ENABLE_MODULES = YES;
 				CODE_SIGN_STYLE = Automatic;
+				CURRENT_PROJECT_VERSION = 2;
 				DEFINES_MODULE = YES;
 				DYLIB_COMPATIBILITY_VERSION = 1;
 				DYLIB_CURRENT_VERSION = 1;
@@ -798,7 +807,7 @@
 					"@executable_path/Frameworks",
 					"@loader_path/Frameworks",
 				);
-				MARKETING_VERSION = 0.2.0;
+				MARKETING_VERSION = 0.5.1;
 				OTHER_LDFLAGS = "-ObjC";
 				PRODUCT_BUNDLE_IDENTIFIER = com.decimal.AudioStreaming;
 				PRODUCT_NAME = "$(TARGET_NAME:c99extidentifier)";
@@ -816,6 +825,7 @@
 			buildSettings = {
 				CLANG_ENABLE_MODULES = YES;
 				CODE_SIGN_STYLE = Automatic;
+				CURRENT_PROJECT_VERSION = 2;
 				DEFINES_MODULE = YES;
 				DYLIB_COMPATIBILITY_VERSION = 1;
 				DYLIB_CURRENT_VERSION = 1;
@@ -828,7 +838,7 @@
 					"@executable_path/Frameworks",
 					"@loader_path/Frameworks",
 				);
-				MARKETING_VERSION = 0.2.0;
+				MARKETING_VERSION = 0.5.1;
 				OTHER_LDFLAGS = "-ObjC";
 				PRODUCT_BUNDLE_IDENTIFIER = com.decimal.AudioStreaming;
 				PRODUCT_NAME = "$(TARGET_NAME:c99extidentifier)";

AudioStreaming/Streaming/Audio Entry/AudioEntryProvider.swift

@@ -46,10 +46,10 @@ final class AudioEntryProvider: AudioEntryProviding {
         FileAudioSource(url: url, underlyingQueue: underlyingQueue)
     }
 
-    func source(for url: URL, headers _: [String: String]) -> CoreAudioStreamSource {
+    func source(for url: URL, headers: [String: String]) -> CoreAudioStreamSource {
         guard !url.isFileURL else {
             return provideFileAudioSource(url: url)
         }
-        return provideAudioSource(url: url, headers: [:])
+        return provideAudioSource(url: url, headers: headers)
     }
 }

AudioStreaming/Streaming/Audio Source/RemoteAudioSource.swift

@@ -29,9 +29,13 @@ public class RemoteAudioSource: AudioStreamSource {
     private var parsedHeaderOutput: HTTPHeaderParserOutput?
     private var relativePosition: Int
     private var seekOffset: Int
+    private var supportsSeek: Bool
 
     internal var metadataStreamProcessor: MetadataStreamSource
 
+    private var shouldTryParsingIcycastHeaders: Bool = false
+    private let icycastHeadersProcessor: IcycastHeadersProcessor
+
     internal var audioFileHint: AudioFileTypeID {
         guard let output = parsedHeaderOutput, output.typeId != 0 else {
             return audioFileType(fileExtension: url.pathExtension)
@@ -47,6 +51,7 @@ public class RemoteAudioSource: AudioStreamSource {
 
     init(networking: NetworkingClient,
          metadataStreamSource: MetadataStreamSource,
+         icycastHeadersProcessor: IcycastHeadersProcessor,
          netStatusProvider: NetStatusProvider,
          retrier: Retrier,
          url: URL,
@@ -59,7 +64,9 @@ public class RemoteAudioSource: AudioStreamSource {
         additionalRequestHeaders = httpHeaders
         relativePosition = 0
         seekOffset = 0
+        supportsSeek = false
         netStatusService = netStatusProvider
+        self.icycastHeadersProcessor = icycastHeadersProcessor
         self.underlyingQueue = underlyingQueue
         streamOperationQueue = OperationQueue()
         streamOperationQueue.underlyingQueue = underlyingQueue
@@ -78,9 +85,11 @@ public class RemoteAudioSource: AudioStreamSource {
         let metadataParser = MetadataParser()
         let metadataProcessor = MetadataStreamProcessor(parser: metadataParser.eraseToAnyParser())
         let netStatusProvider = NetStatusService(network: NWPathMonitor())
+        let icyheaderProcessor = IcycastHeadersProcessor()
         let retrierTimout = Retrier(interval: .seconds(1), maxInterval: 5, underlyingQueue: nil)
         self.init(networking: networking,
                   metadataStreamSource: metadataProcessor,
+                  icycastHeadersProcessor: icyheaderProcessor,
                   netStatusProvider: netStatusProvider,
                   retrier: retrierTimout,
                   url: url,
@@ -116,14 +125,14 @@ public class RemoteAudioSource: AudioStreamSource {
         relativePosition = 0
         seekOffset = offset
 
-        if let supportsSeek = parsedHeaderOutput?.supportsSeek,
-           !supportsSeek, offset != relativePosition
-        {
+        if !supportsSeek, offset != relativePosition {
             return
         }
 
         retrierTimeout.cancel()
         metadataStreamProcessor.reset()
+        icycastHeadersProcessor.reset()
+        shouldTryParsingIcycastHeaders = false
 
         performOpen(seek: offset)
     }
@@ -189,16 +198,26 @@ public class RemoteAudioSource: AudioStreamSource {
     private func handleStreamEvent(event: NetworkDataStream.StreamResult) {
         switch event {
         case let .success(value):
-            if let data = value.data {
+            if let audioData = value.data {
                 addStreamOperation { [weak self] in
                     guard let self = self else { return }
-                    if self.metadataStreamProcessor.canProccessMetadata {
-                        let extractedAudioData = self.metadataStreamProcessor.proccessMetadata(data: data)
-                        self.delegate?.dataAvailable(source: self, data: extractedAudioData)
-                    } else {
-                        self.delegate?.dataAvailable(source: self, data: data)
+                    if self.shouldTryParsingIcycastHeaders {
+                        let (header, extractedAudio) = self.icycastHeadersProcessor.proccess(data: audioData)
+                        if let header = header {
+                            self.shouldTryParsingIcycastHeaders = false
+                            let parser = IcycastHeaderParser()
+                            self.parsedHeaderOutput = parser.parse(input: header)
+                            if let metadataStep = self.parsedHeaderOutput?.metadataStep {
+                                self.metadataStreamProcessor.metadataAvailable(step: metadataStep)
+                            }
+
+                            let audioCount = self.processAudio(data: extractedAudio)
+                            self.relativePosition += audioCount
+                            return
+                        }
                     }
-                    self.relativePosition += data.count
+                    let audioCount = self.processAudio(data: audioData)
+                    self.relativePosition += audioCount
                 }
             }
         case .failure:
@@ -211,20 +230,49 @@ public class RemoteAudioSource: AudioStreamSource {
         }
     }
 
+    /// Processing audio data, extracting metadata if needed.
+    /// - Parameter data: The audio to be processed
+    /// - Returns: An `Int` value representing the amount of audio data bytes.
+    private func processAudio(data: Data) -> Int {
+        if self.metadataStreamProcessor.canProccessMetadata {
+            let extractedAudioData = self.metadataStreamProcessor.proccessMetadata(data: data)
+            self.delegate?.dataAvailable(source: self, data: extractedAudioData)
+            return extractedAudioData.count
+        } else {
+            self.delegate?.dataAvailable(source: self, data: data)
+            return data.count
+        }
+    }
+
     private func parseResponseHeader(response: HTTPURLResponse?) {
         guard let response = response else { return }
         let httpStatusCode = response.statusCode
         let parser = HTTPHeaderParser()
         parsedHeaderOutput = parser.parse(input: response)
+
+        if parsedHeaderOutput == nil {
+            shouldTryParsingIcycastHeaders = true
+            checkHTTP(statusCode: httpStatusCode)
+            return
+        }
+
+        if let acceptRanges = parser.value(forHTTPHeaderField: HeaderField.acceptRanges, in: response) {
+            supportsSeek = acceptRanges != "none"
+        }
+
         // check to see if we have metadata to proccess
         if let metadataStep = parsedHeaderOutput?.metadataStep {
             metadataStreamProcessor.metadataAvailable(step: metadataStep)
         }
+        checkHTTP(statusCode: httpStatusCode)
+    }
+
+    private func checkHTTP(statusCode: Int) {
         // check for error
-        if httpStatusCode == 416 { // range not satisfied error
+        if statusCode == 416 { // range not satisfied error
             if length >= 0 { seekOffset = length }
             delegate?.endOfFileOccured(source: self)
-        } else if httpStatusCode >= 300 {
+        } else if statusCode >= 300 {
             delegate?.errorOccured(source: self, error: NetworkError.serverError)
         }
     }
@@ -242,7 +290,7 @@ public class RemoteAudioSource: AudioStreamSource {
         urlRequest.addValue("1", forHTTPHeaderField: "Icy-MetaData")
         urlRequest.addValue("identity", forHTTPHeaderField: "Accept-Encoding")
 
-        if let supportsSeek = parsedHeaderOutput?.supportsSeek, supportsSeek, seekOffset > 0 {
+        if supportsSeek && seekOffset > 0 {
             urlRequest.addValue("bytes=\(seekOffset)-", forHTTPHeaderField: "Range")
         }
         return urlRequest
@@ -281,4 +329,3 @@ extension RemoteAudioSource: MetadataStreamSourceDelegate {
         delegate?.metadataReceived(data: data)
     }
 }
-

AudioStreaming/Streaming/AudioPlayer/AudioPlayer.swift

@@ -6,7 +6,7 @@
 import AVFoundation
 import CoreAudio
 
-public final class AudioPlayer {
+open class AudioPlayer {
     public weak var delegate: AudioPlayerDelegate?
 
     public var muted: Bool {
@@ -70,7 +70,14 @@ public final class AudioPlayer {
         playerContext.entriesLock.lock()
         let playingEntry = playerContext.audioPlayingEntry
         playerContext.entriesLock.unlock()
-        guard let entry = playingEntry, !entry.seekRequest.requested else { return 0 }
+        guard let entry = playingEntry else { return 0 }
+        entry.seekRequest.lock.lock()
+        let seekRequested = entry.seekRequest.requested
+        let seekTime = entry.seekRequest.time
+        entry.seekRequest.lock.unlock()
+        if seekRequested {
+            return seekTime
+        }
         return entry.progress
     }
 
@@ -88,28 +95,33 @@ public final class AudioPlayer {
     private var stateBeforePaused: InternalState = .initial
 
     /// The underlying `AVAudioEngine` object
-    let audioEngine = AVAudioEngine()
+    private let audioEngine = AVAudioEngine()
     /// An `AVAudioUnit` object that represents the audio player
     private(set) var player = AVAudioUnit()
     /// An `AVAudioUnitTimePitch` that controls the playback rate of the audio engine
-    let rateNode = AVAudioUnitTimePitch()
+    private let rateNode = AVAudioUnitTimePitch()
 
     /// A Boolean value that indicates whether the audio engine is running.
     /// `true` if the engine is running, otherwise, `false`
-    var isEngineRunning: Bool { audioEngine.isRunning }
+    public var isEngineRunning: Bool { audioEngine.isRunning }
+
+    /// The `AVAudioMixerNode` as created by the underlying audio engine
+    public var mainMixerNode: AVAudioMixerNode {
+        audioEngine.mainMixerNode
+    }
 
     /// An object representing the context of the audio render.
     /// Holds the audio buffer and in/out lists as required by the audio rendering
-    let rendererContext: AudioRendererContext
+    private let rendererContext: AudioRendererContext
     /// An object representing the context of the player.
     /// Holds the player's state, current playing and reading entries.
-    let playerContext: AudioPlayerContext
+    private let playerContext: AudioPlayerContext
 
-    let fileStreamProcessor: AudioFileStreamProcessor
-    let playerRenderProcessor: AudioPlayerRenderProcessor
+    private let fileStreamProcessor: AudioFileStreamProcessor
+    private let playerRenderProcessor: AudioPlayerRenderProcessor
 
     private let audioReadSource: DispatchTimerSource
-    private let underlyingQueue = DispatchQueue(label: "streaming.core.queue", qos: .userInitiated, attributes: .concurrent)
+    private let serializationQueue: DispatchQueue
     private let sourceQueue: DispatchQueue
 
     private let entryProvider: AudioEntryProviding
@@ -123,7 +135,8 @@ public final class AudioPlayer {
         playerContext = AudioPlayerContext()
         entriesQueue = PlayerQueueEntries()
 
-        sourceQueue = DispatchQueue(label: "source.queue", qos: .userInitiated, target: underlyingQueue)
+        serializationQueue = DispatchQueue(label: "streaming.core.queue", qos: .userInitiated)
+        sourceQueue = DispatchQueue(label: "source.queue", qos: .userInitiated)
         audioReadSource = DispatchTimerSource(interval: .milliseconds(200), queue: sourceQueue)
 
         entryProvider = AudioEntryProvider(networkingClient: NetworkingClient(),
@@ -144,7 +157,6 @@ public final class AudioPlayer {
     }
 
     deinit {
-        // todo more stuff to release...
         playerContext.audioPlayingEntry?.close()
         clearQueue()
         stopReadProccessFromSource()
@@ -167,18 +179,21 @@ public final class AudioPlayer {
     public func play(url: URL, headers: [String: String]) {
         let audioEntry = entryProvider.provideAudioEntry(url: url, headers: headers)
         audioEntry.delegate = self
-        clearQueue()
-        entriesQueue.enqueue(item: audioEntry, type: .upcoming)
-        playerContext.setInternalState(to: .pendingNext)
 
         checkRenderWaitingAndNotifyIfNeeded()
-        sourceQueue.async { [weak self] in
-            guard let self = self else { return }
+        serializationQueue.sync {
+            clearQueue()
+            entriesQueue.enqueue(item: audioEntry, type: .upcoming)
+            playerContext.setInternalState(to: .pendingNext)
             do {
                 try self.startEngineIfNeeded()
             } catch {
                 self.raiseUnxpected(error: .audioSystemError(.engineFailure))
             }
+        }
+
+        sourceQueue.async { [weak self] in
+            guard let self = self else { return }
             self.processSource()
             self.startReadProcessFromSourceIfNeeded()
         }
@@ -186,19 +201,47 @@ public final class AudioPlayer {
 
     /// Queues the specified URL
     ///
-    /// - Parameter url: A `URL` specifying the audio context to be played.
+    /// - Parameter url: A `URL` specifying the audio content to be played.
     public func queue(url: URL) {
         queue(url: url, headers: [:])
     }
 
+    /// Queues the specified URLs
+    ///
+    /// - Parameter url: A `URL` specifying the audio content to be played.
+    public func queue(urls: [URL]) {
+        queue(urls: urls, headers: [:])
+    }
+
     /// Queues the specified URL
     ///
-    /// - Parameter url: A `URL` specifying the audio context to be played.
+    /// - Parameter url: A `URL` specifying the audio content to be played.
     /// - parameter headers: A `Dictionary` specifying any additional headers to be pass to the network request.
     public func queue(url: URL, headers: [String: String]) {
-        let audioEntry = entryProvider.provideAudioEntry(url: url, headers: headers)
-        audioEntry.delegate = self
-        entriesQueue.enqueue(item: audioEntry, type: .upcoming)
+        serializationQueue.sync {
+            let audioEntry = entryProvider.provideAudioEntry(url: url, headers: headers)
+            audioEntry.delegate = self
+            entriesQueue.enqueue(item: audioEntry, type: .upcoming)
+        }
+        checkRenderWaitingAndNotifyIfNeeded()
+        sourceQueue.async { [weak self] in
+            self?.processSource()
+        }
+    }
+
+    /// Queues the specified URLs
+    ///
+    /// - Parameter url: A array of `URL`s specifying the audio content to be played.
+    /// - parameter headers: A `Dictionary` specifying any additional headers to be pass to the network request.
+    public func queue(urls: [URL], headers: [String: String]) {
+        serializationQueue.sync {
+            for url in urls {
+                let audioEntry = entryProvider.provideAudioEntry(url: url, headers: headers)
+                audioEntry.delegate = self
+                entriesQueue.enqueue(item: audioEntry, type: .upcoming)
+            }
+        }
+        checkRenderWaitingAndNotifyIfNeeded()
         sourceQueue.async { [weak self] in
             self?.processSource()
         }
@@ -208,8 +251,11 @@ public final class AudioPlayer {
     public func stop() {
         guard playerContext.internalState != .stopped else { return }
 
-        stopEngine(reason: .userAction)
         stopReadProccessFromSource()
+        serializationQueue.sync {
+            stopEngine(reason: .userAction)
+        }
+        checkRenderWaitingAndNotifyIfNeeded()
         sourceQueue.async { [weak self] in
             guard let self = self else { return }
             self.playerContext.audioReadingEntry?.delegate = nil
@@ -226,7 +272,6 @@ public final class AudioPlayer {
 
             self.processSource()
         }
-        checkRenderWaitingAndNotifyIfNeeded()
     }
 
     /// Pauses the audio playback
@@ -234,8 +279,9 @@ public final class AudioPlayer {
         if playerContext.internalState != .paused, playerContext.internalState.contains(.running) {
             stateBeforePaused = playerContext.internalState
             playerContext.setInternalState(to: .paused)
-
-            pauseEngine()
+            serializationQueue.sync {
+                pauseEngine()
+            }
             stopReadProccessFromSource()
             playerContext.audioPlayingEntry?.suspend()
             sourceQueue.async { [weak self] in
@@ -248,23 +294,25 @@ public final class AudioPlayer {
     public func resume() {
         guard playerContext.internalState == .paused else { return }
         playerContext.setInternalState(to: stateBeforePaused)
-        // check if seek time requested and reset buffers
-        do {
-            try startEngine()
-        } catch {
-            Logger.debug("resuming audio engine failed: %@", category: .generic, args: error.localizedDescription)
-        }
-
-        if let playingEntry = playerContext.audioReadingEntry {
-            if playingEntry.seekRequest.requested {
-                rendererContext.resetBuffers()
+        serializationQueue.sync {
+            do {
+                try startEngine()
+            } catch {
+                Logger.debug("resuming audio engine failed: %@", category: .generic, args: error.localizedDescription)
             }
-            playingEntry.resume()
+            if let playingEntry = playerContext.audioReadingEntry {
+                if playingEntry.seekRequest.requested {
+                    rendererContext.resetBuffers()
+                }
+                playingEntry.resume()
+            }
+            startPlayer(resetBuffers: false)
         }
-        startPlayer(resetBuffers: false)
         startReadProcessFromSourceIfNeeded()
     }
 
+    /// Seeks the audio to the specified time.
+    /// - Parameter time: A `Double` value specifing the time of the requested seek in seconds
     public func seek(to time: Double) {
         guard let playingEntry = playerContext.audioPlayingEntry else {
             return
@@ -287,10 +335,16 @@ public final class AudioPlayer {
         }
     }
 
+    /// Attaches the given `AVAudioNode` to the engine
+    /// - Note: The node will be added after the default rate node
+    /// - Parameter node: An instance of `AVAudioNode`
     public func attach(node: AVAudioNode) {
         attach(nodes: [node])
     }
 
+    /// Attaches the given `AVAudioNode`s to the engine
+    /// - Note: The nodes will be added after the default rate node
+    /// - Parameter node: An array of `AVAudioNode` instances
     public func attach(nodes: [AVAudioNode]) {
         nodes.forEach { node in
             customAttachedNodes.append(node)
@@ -300,6 +354,8 @@ public final class AudioPlayer {
         reattachCustomNodes()
     }
 
+    /// Detaches the given `AVAudioNode` from the engine
+    /// - Parameter node: An instance of `AVAudioNode`
     public func detach(node: AVAudioNode) {
         guard customAttachedNodes.contains(node) else {
             return
@@ -309,6 +365,8 @@ public final class AudioPlayer {
         reattachCustomNodes()
     }
 
+    /// Detaches the given `AVAudioNode`s from the engine
+    /// - Parameter node: An array of `AVAudioNode` instances
     public func detachCustomAttachedNodes() {
         customAttachedNodes.forEach { node in
             audioEngine.detach(node)
@@ -375,9 +433,11 @@ public final class AudioPlayer {
 
         playerRenderProcessor.audioFinishedPlaying = { [weak self] entry in
             guard let self = self else { return }
-            self.sourceQueue.async {
+            self.serializationQueue.sync {
                 let nextEntry = self.entriesQueue.dequeue(type: .buffering)
                 self.processFinishPlaying(entry: entry, with: nextEntry)
+            }
+            self.sourceQueue.async {
                 self.processSource()
             }
         }
@@ -455,10 +515,6 @@ public final class AudioPlayer {
     ///
     /// - parameter reason: A value of `AudioPlayerStopReason` indicating the reason the engine stopped.
     private func stopEngine(reason: AudioPlayerStopReason) {
-        guard isEngineRunning && player.auAudioUnit.isRunning else {
-            Logger.debug("already already stopped 🛑", category: .generic)
-            return
-        }
         audioEngine.stop()
         player.auAudioUnit.stopHardware()
         rendererContext.resetBuffers()
@@ -491,11 +547,8 @@ public final class AudioPlayer {
         if resetBuffers {
             rendererContext.resetBuffers()
         }
-        if !isEngineRunning && !player.auAudioUnit.isRunning {
-            Logger.debug("trying to start the player when audio engine and player are already running", category: .generic)
-            return
-        }
         do {
+            try startEngineIfNeeded()
             try player.auAudioUnit.allocateRenderResources()
             try player.auAudioUnit.startHardware()
         } catch {
@@ -542,7 +595,7 @@ public final class AudioPlayer {
                 let entry = entriesQueue.dequeue(type: .upcoming)
                 let shouldStartPlaying = playerContext.audioPlayingEntry == nil
                 playerContext.setInternalState(to: .waitingForData)
-                setCurrentReading(entry: entry, startPlaying: shouldStartPlaying, shouldClearQueue: true)
+                setCurrentReading(entry: entry, startPlaying: shouldStartPlaying, shouldClearQueue: false)
             } else if playerContext.audioPlayingEntry == nil {
                 if playerContext.internalState != .stopped {
                     stopReadProccessFromSource()
@@ -574,7 +627,8 @@ public final class AudioPlayer {
     }
 
     private func proccessSeekTime() {
-        assert(playerContext.audioReadingEntry === playerContext.audioPlayingEntry, "reading and playing entry must be the same")
+        assert(playerContext.audioReadingEntry === playerContext.audioPlayingEntry,
+               "reading and playing entry must be the same")
         fileStreamProcessor.processSeek()
     }
 
@@ -662,7 +716,9 @@ public final class AudioPlayer {
             playerContext.audioPlayingEntry = nil
             playerContext.entriesLock.unlock()
         }
-        processSource()
+        sourceQueue.async { [weak self] in
+            self?.processSource()
+        }
         checkRenderWaitingAndNotifyIfNeeded()
     }
 

AudioStreaming/Streaming/AudioPlayer/Processors/AudioFileStreamProcessor.swift

@@ -191,7 +191,11 @@ final class AudioFileStreamProcessor {
             guard AudioFileStreamGetProperty(fileStream, kAudioFileStreamProperty_MagicCookieData, &cookieSize, &cookie) == noErr else {
                 return
             }
-            guard AudioFileStreamSetProperty(fileStream, kAudioConverterDecompressionMagicCookie, cookieSize, cookie) == noErr else {
+            guard let converter = audioConverter else {
+                fileStreamCallback?(.raiseError(.audioSystemError(.fileStreamError(.unknownError))))
+                 return
+            }
+            guard AudioConverterSetProperty(converter, kAudioConverterDecompressionMagicCookie, cookieSize, cookie) == noErr else {
                 fileStreamCallback?(.raiseError(.audioSystemError(.fileStreamError(.unknownError))))
                 return
             }
@@ -446,7 +450,7 @@ final class AudioFileStreamProcessor {
                     fillUsedFrames(framesCount: framesAdded)
                     return
                 } else if status != 0 {
-                    /// raise undexpected error... codec error
+                    fileStreamCallback?(.raiseError(.codecError))
                     return
                 }
 
@@ -475,7 +479,7 @@ final class AudioFileStreamProcessor {
                     fillUsedFrames(framesCount: framesAdded)
                     continue packetProccess
                 } else if status != 0 {
-                    /// raise undexpected error... codec error
+                    fileStreamCallback?(.raiseError(.codecError))
                     return
                 }
             } else {
@@ -502,7 +506,7 @@ final class AudioFileStreamProcessor {
                     fillUsedFrames(framesCount: framesAdded)
                     continue packetProccess
                 } else if status != 0 {
-                    /// raise undexpected error... codec error
+                    fileStreamCallback?(.raiseError(.codecError))
                     return
                 }
             }

AudioStreaming/Streaming/AudioPlayer/Processors/IcycastHeadersProcessor.swift

@@ -0,0 +1,91 @@
+//
+//  IcycastHeadersProcessor.swift
+//  AudioStreaming
+//
+//  Created by Dimitrios C on 14/02/2021.
+//  Copyright © 2021 Decimal. All rights reserved.
+//
+
+import Foundation
+
+/// ICY is built on HTTP some old servers might still send headers in the stream.
+/// From a server point of view, this should be considered deprecated and should not be used as it might break HTML5 compatibility.
+/// Although there are some servers still using this, this class will extract those headers from the stream
+///
+/// The format of the headers is as follows:
+/// ```
+/// =================================================================
+/// [ ICY 200 OK                                                    ]
+/// [ icy-mentaint: the number of bytes between 2 metadata chunks   ]
+/// [ icy-br: send the bitrate in kilobits per second               ]
+/// [ icy-genre: sends the genre                                    ]
+/// [ icy-name: sends the stream's name                             ]
+/// [ icy-url: is the URL of the radio station                      ]
+/// [ icy-pub: can be 1 or 0 to tell if it is listed or not         ]
+/// =================================================================
+/// ```
+
+final class IcycastHeadersProcessor {
+
+    private var icecastHeaders = Data(capacity: 1024)
+    private var searchComplete = false
+    private var iceHeaderAvailable = false
+
+    func reset() {
+        icecastHeaders = Data(capacity: 1024)
+        searchComplete = false
+        iceHeaderAvailable = false
+    }
+
+    @inline(__always)
+    func proccess(data: Data) -> (Data?, Data) {
+        let stopProccessingCheckOne: [UInt8] = Array("\n\n".utf8)
+        let stopProccessingCheckTwo: [UInt8] = Array("\r\n\r\n".utf8)
+        let icyPrefix: [UInt8] = Array("ICY ".utf8)
+        let httpPrefix: [UInt8] = Array("HTTP".utf8)
+        return data.withUnsafeBytes { buffer -> (Data?, Data) in
+            var bytesRead = 0
+            let bytes = buffer.baseAddress!.assumingMemoryBound(to: UInt8.self)
+            // Read through the bytes and stop when our search is complete
+            // Since we don't know the amount of bytes to be proccessed
+            // we add each character up until we found on of the checks as defined above.
+            while bytesRead < buffer.count, !searchComplete {
+                let pointer = bytes + bytesRead
+                icecastHeaders.append(pointer, count: 1)
+
+                if icecastHeaders.count >= stopProccessingCheckOne.count {
+                    if icecastHeaders.suffix(stopProccessingCheckOne.count) == stopProccessingCheckOne {
+                        iceHeaderAvailable = true
+                        searchComplete = true
+                        break
+                    }
+                }
+
+                if icecastHeaders.count >= stopProccessingCheckTwo.count {
+                    if icecastHeaders.suffix(stopProccessingCheckTwo.count) == stopProccessingCheckTwo {
+                        iceHeaderAvailable = true
+                        searchComplete = true
+                        break
+                    }
+                }
+
+                if icecastHeaders.count >= icyPrefix.count {
+                    // in case the first 4 chars are not "ICY " nor "HTTP" then we stop the flow
+                    if icecastHeaders[..<icyPrefix.count].elementsEqual(icyPrefix) == false &&
+                        icecastHeaders[..<httpPrefix.count].elementsEqual(httpPrefix) == false {
+                        iceHeaderAvailable = false
+                        searchComplete = true
+                    }
+                }
+
+                bytesRead += 1
+            }
+            if !iceHeaderAvailable {
+                return (nil, data)
+            }
+            let extractedAudio = data[icecastHeaders.count...]
+            iceHeaderAvailable = false
+            return (icecastHeaders, extractedAudio)
+        }
+    }
+}

AudioStreaming/Streaming/Parsers/HTTPHeaderParser.swift

@@ -18,21 +18,28 @@ enum IcyHeaderField {
 }
 
 struct HTTPHeaderParserOutput {
-    let supportsSeek: Bool
     let fileLength: Int
     let typeId: AudioFileTypeID
     // Metadata Support
     let metadataStep: Int
 }
 
-struct HTTPHeaderParser: Parser {
+protocol HTTPHeaderParsing: Parser {
+    /// Returns the value for the given field of the headers in the given `HTTPURLResponse`
+    ///
+    /// - Parameters:
+    ///   - field: The header field to be searched
+    ///   - response: The `HTTPURLResponse` for the header
+    /// - Returns: A `String` if the field exists in the headers otherwise `nil`
+    func value(forHTTPHeaderField field: String, in response: HTTPURLResponse) -> String?
+}
+
+struct HTTPHeaderParser: HTTPHeaderParsing {
     typealias Input = HTTPURLResponse
     typealias Output = HTTPHeaderParserOutput?
 
     func parse(input: HTTPURLResponse) -> HTTPHeaderParserOutput? {
-        guard let headers = input.allHeaderFields as? [String: String], !headers.isEmpty else { return nil }
-
-        let supportsSeek = headers[HeaderField.acceptRanges] != "none"
+        guard let headers = input.allHeaderFields as? [String: String], headers.count > 2 else { return nil }
 
         var typeId: UInt32 = 0
         if let contentType = input.mimeType {
@@ -41,13 +48,12 @@ struct HTTPHeaderParser: Parser {
 
         var fileLength: Int = 0
         if input.statusCode == 200 {
-            if let contentLength = headers[HeaderField.contentLength],
-               let length = Int(contentLength)
-            {
+            let contentLength = value(forHTTPHeaderField: HeaderField.contentLength, in: input)
+            if let contentLength = contentLength, let length = Int(contentLength) {
                 fileLength = length
             }
         } else if input.statusCode == 206 {
-            if let contentLength = headers[HeaderField.contentRange] {
+            if let contentLength = value(forHTTPHeaderField: HeaderField.contentRange, in: input) {
                 let components = contentLength.components(separatedBy: "/")
                 if components.count == 2 {
                     if let last = components.last, let length = Int(last) {
@@ -58,15 +64,38 @@ struct HTTPHeaderParser: Parser {
         }
 
         var metadataStep = 0
-        if let icyMetaint = headers[IcyHeaderField.icyMentaint],
+        if let icyMetaint = value(forHTTPHeaderField: IcyHeaderField.icyMentaint, in: input),
            let intValue = Int(icyMetaint)
         {
             metadataStep = intValue
         }
 
-        return HTTPHeaderParserOutput(supportsSeek: supportsSeek,
-                                      fileLength: fileLength,
+        return HTTPHeaderParserOutput(fileLength: fileLength,
                                       typeId: typeId,
                                       metadataStep: metadataStep)
     }
 }
+
+extension Parser where Self: HTTPHeaderParsing {
+    func value(forHTTPHeaderField field: String, in response: HTTPURLResponse) -> String? {
+        if #available(iOS 13.0, *) {
+            return response.value(forHTTPHeaderField: field)
+        } else {
+            if let fields = response.allHeaderFields as? [String: String] {
+                return valueForCaseInsensitiveKey(field, fields: fields)
+            } else {
+                return nil
+            }
+        }
+    }
+
+    private func valueForCaseInsensitiveKey(_ key: String, fields: [String: String]) -> String? {
+        let keyToBeFound = key.lowercased()
+        for (key, value) in fields {
+            if key.lowercased() == keyToBeFound {
+                return value
+            }
+        }
+        return nil
+    }
+}

AudioStreaming/Streaming/Parsers/IcycastHeaderParser.swift

@@ -0,0 +1,34 @@
+//
+//  IcycastHeaderParser.swift
+//  AudioStreaming
+//
+//  Created by Dimitrios C on 14/02/2021.
+//  Copyright © 2021 Decimal. All rights reserved.
+//
+
+import Foundation
+
+struct IcycastHeaderParser: Parser {
+
+    func parse(input: Data) -> HTTPHeaderParserOutput? {
+
+        guard let icecastValue = String(data: input, encoding: .utf8) else {
+            return nil
+        }
+        let headers = icecastValue.components(separatedBy: CharacterSet(charactersIn: "\r\n"))
+        var result = [String: String]()
+        for header in headers where !header.isEmpty {
+            let values = header.split(separator: ":", maxSplits: 1, omittingEmptySubsequences: true)
+            if let key = values.first, let value = values.last {
+                result[String(key)] = String(value)
+            }
+        }
+        let metadataStep = Int(result[IcyHeaderField.icyMentaint] ?? "") ?? 0
+        let contentType = result[HeaderField.contentType.lowercased()] ?? "audio/mpeg"
+        let typeId = audioFileType(mimeType: contentType)
+
+        return HTTPHeaderParserOutput(fileLength: 0,
+                                      typeId: typeId,
+                                      metadataStep: metadataStep)
+    }
+}

AudioStreamingTests/Streaming/Parsers/HTTPHeaderParserTests.swift

@@ -32,8 +32,7 @@ class HTTPHeaderParserTests: XCTestCase {
 
         // When
         let headers: [String: String] =
-            [HeaderField.acceptRanges: "range",
-             HeaderField.contentLength: "1000",
+            [HeaderField.contentLength: "1000",
              HeaderField.contentType: "audio/mp3",
              IcyHeaderField.icyMentaint: "16000"]
         let httpURLResponse = HTTPURLResponse(url: URL(string: "www.google.com")!,
@@ -46,23 +45,21 @@ class HTTPHeaderParserTests: XCTestCase {
         // Then
         XCTAssertNotNil(output)
         XCTAssertEqual(output!.fileLength, 1000)
-        XCTAssertEqual(output!.supportsSeek, true)
         XCTAssertEqual(output!.typeId, kAudioFileMP3Type)
         XCTAssertEqual(output!.metadataStep, 16000)
     }
 
-    func testReturnCorrectValuesOnRequestThatSupportsSeekRanges() throws {
+    func testReturnCorectValuesOnCaseInsensitiveHeaderFiels() throws {
         // Given
         let parser = HTTPHeaderParser()
 
         // When
         let headers: [String: String] =
-            [HeaderField.acceptRanges: "range",
-             HeaderField.contentLength: "1000",
-             HeaderField.contentType: "audio/mp3",
-             HeaderField.contentRange: "100/1000"]
+            [HeaderField.contentLength.lowercased(): "1000",
+             HeaderField.contentType.lowercased(): "audio/mp3",
+             IcyHeaderField.icyMentaint.lowercased(): "16000"]
         let httpURLResponse = HTTPURLResponse(url: URL(string: "www.google.com")!,
-                                              statusCode: 206,
+                                              statusCode: 200,
                                               httpVersion: "",
                                               headerFields: headers)
 
@@ -71,7 +68,7 @@ class HTTPHeaderParserTests: XCTestCase {
         // Then
         XCTAssertNotNil(output)
         XCTAssertEqual(output!.fileLength, 1000)
-        XCTAssertEqual(output!.supportsSeek, true)
         XCTAssertEqual(output!.typeId, kAudioFileMP3Type)
+        XCTAssertEqual(output!.metadataStep, 16000)
     }
 }

README.md

@@ -3,7 +3,7 @@
 # AudioStreaming
 An AudioPlayer/Streaming library for iOS written in Swift, allows playback of online audio streaming, local file as well as gapless queueing.
 
-Under the hood `AudioStreaming` uses `AVAudioEngine` and `CoreAudio` for playback and provides an easy way of applying real-time [audio enhancements](https://developer.apple.com/documentation/avfoundation/audio_playback_recording_and_processing/avaudioengine/audio_units?language=swift).
+Under the hood `AudioStreaming` uses `AVAudioEngine` and `CoreAudio` for playback and provides an easy way of applying real-time [audio enhancements](https://developer.apple.com/documentation/avfaudio/audio_engine/audio_units).
 
 #### Supported audio
 - Online streaming (Shoutcast/ICY streams) with metadata parsing 
@@ -35,8 +35,14 @@ player.play(url: URL(fileURLWithPath: "your-local-path/to/audio-file.mp3")!)
 ### Queueing audio files
 ```
 let player = AudioPlayer()
+// when you want to queue a single url
 player.queue(url: URL(string: "https://your-remote-url/to/audio-file.mp3")!)
-player.queue(url: URL(fileURLWithPath: "your-local-path/to/audio-file.mp3")!)
+
+// or if you want to queue a list of urls use
+player.queue(urls: [
+    URL(fileURLWithPath: "your-local-path/to/audio-file.mp3")!,
+    URL(fileURLWithPath: "your-local-path/to/audio-file-2.mp3")!
+])
 ```
 
 ### Adjusting playback properties