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+/*
+ Copyright (c) 2010 Steve Oldmeadow
+ 
+ Permission is hereby granted, free of charge, to any person obtaining a copy
+ of this software and associated documentation files (the "Software"), to deal
+ in the Software without restriction, including without limitation the rights
+ to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ copies of the Software, and to permit persons to whom the Software is
+ furnished to do so, subject to the following conditions:
+ 
+ The above copyright notice and this permission notice shall be included in
+ all copies or substantial portions of the Software.
+ 
+ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ THE SOFTWARE.
+ 
+ $Id$
+ */
+
+
+#import "CDAudioManager.h"
+
+NSString * const kCDN_AudioManagerInitialised = @"kCDN_AudioManagerInitialised";
+
+//NSOperation object used to asynchronously initialise 
+@implementation CDAsynchInitialiser
+
+-(void) main {
+        [super main];
+        [CDAudioManager sharedManager];
+}       
+
+@end
+
+@implementation CDLongAudioSource
+
+@synthesize audioSourcePlayer, audioSourceFilePath, delegate, backgroundMusic;
+
+-(id) init {
+        if ((self = [super init])) {
+                state = kLAS_Init;
+                volume = 1.0f;
+                mute = NO;
+                enabled_ = YES;
+        }
+        return self;
+}
+
+-(void) dealloc {
+        CDLOGINFO(@"Denshion::CDLongAudioSource - deallocating %@", self);
+        [audioSourcePlayer release];
+        [audioSourceFilePath release];
+        [super dealloc];
+}       
+
+-(void) load:(NSString*) filePath {
+        //We have alread loaded a file previously,  check if we are being asked to load the same file
+        if (state == kLAS_Init || ![filePath isEqualToString:audioSourceFilePath]) {
+                CDLOGINFO(@"Denshion::CDLongAudioSource - Loading new audio source %@",filePath);
+                //New file
+                if (state != kLAS_Init) {
+                        [audioSourceFilePath release];//Release old file path
+                        [audioSourcePlayer release];//Release old AVAudioPlayer, they can't be reused
+                }
+                audioSourceFilePath = [filePath copy];
+                NSError *error = nil;
+                NSString *path = [CDUtilities fullPathFromRelativePath:audioSourceFilePath];
+                audioSourcePlayer = [(AVAudioPlayer*)[AVAudioPlayer alloc] initWithContentsOfURL:[NSURL fileURLWithPath:path] error:&error];
+                if (error == nil) {
+                        [audioSourcePlayer prepareToPlay];
+                        audioSourcePlayer.delegate = self;
+                        if (delegate && [delegate respondsToSelector:@selector(cdAudioSourceFileDidChange:)]) {
+                                //Tell our delegate the file has changed
+                                [delegate cdAudioSourceFileDidChange:self];
+                        }       
+                } else {
+                        CDLOG(@"Denshion::CDLongAudioSource - Error initialising audio player: %@",error);
+                }       
+        } else {
+                //Same file - just return it to a consistent state
+                [self pause];
+                [self rewind];
+        }
+        audioSourcePlayer.volume = volume;
+        audioSourcePlayer.numberOfLoops = numberOfLoops;
+        state = kLAS_Loaded;
+}       
+
+-(void) play {
+        if (enabled_) {
+                self->systemPaused = NO;
+                [audioSourcePlayer play];
+        } else {
+                CDLOGINFO(@"Denshion::CDLongAudioSource long audio source didn't play because it is disabled");
+        }       
+}       
+
+-(void) stop {
+        [audioSourcePlayer stop];
+}       
+
+-(void) pause {
+        [audioSourcePlayer pause];
+}       
+
+-(void) rewind {
+        [audioSourcePlayer setCurrentTime:0];
+}
+
+-(void) resume {
+        [audioSourcePlayer play];
+}       
+
+-(BOOL) isPlaying {
+        if (state != kLAS_Init) {
+                return [audioSourcePlayer isPlaying];
+        } else {
+                return NO;
+        }
+}
+
+-(void) setVolume:(float) newVolume
+{
+        volume = newVolume;
+        if (state != kLAS_Init && !mute) {
+                audioSourcePlayer.volume = newVolume;
+        }       
+}
+
+-(float) volume 
+{
+        return volume;
+}
+
+#pragma mark Audio Interrupt Protocol
+-(BOOL) mute
+{
+        return mute;
+}       
+
+-(void) setMute:(BOOL) muteValue 
+{
+        if (mute != muteValue) {
+                if (mute) {
+                        //Turn sound back on
+                        audioSourcePlayer.volume = volume;
+                } else {
+                        audioSourcePlayer.volume = 0.0f;
+                }
+                mute = muteValue;
+        }       
+}       
+
+-(BOOL) enabled 
+{
+        return enabled_;
+}       
+
+-(void) setEnabled:(BOOL)enabledValue 
+{
+        if (enabledValue != enabled_) {
+                enabled_ = enabledValue;
+                if (!enabled_) {
+                        //"Stop" the sounds
+                        [self pause];
+                        [self rewind];
+                }       
+        }       
+}       
+
+-(NSInteger) numberOfLoops {
+        return numberOfLoops;
+}       
+
+-(void) setNumberOfLoops:(NSInteger) loopCount
+{
+        audioSourcePlayer.numberOfLoops = loopCount;
+        numberOfLoops = loopCount;
+}       
+
+- (void)audioPlayerDidFinishPlaying:(AVAudioPlayer *)player successfully:(BOOL)flag {
+        CDLOGINFO(@"Denshion::CDLongAudioSource - audio player finished");
+#if TARGET_IPHONE_SIMULATOR     
+        CDLOGINFO(@"Denshion::CDLongAudioSource - workaround for OpenAL clobbered audio issue");
+        //This is a workaround for an issue in all simulators (tested to 3.1.2).  Problem is 
+        //that OpenAL audio playback is clobbered when an AVAudioPlayer stops.  Workaround
+        //is to keep the player playing on an endless loop with 0 volume and then when
+        //it is played again reset the volume and set loop count appropriately.
+        //NB: this workaround is not foolproof but it is good enough for most situations.
+        player.numberOfLoops = -1;
+        player.volume = 0;
+        [player play];
+#endif  
+        if (delegate && [delegate respondsToSelector:@selector(cdAudioSourceDidFinishPlaying:)]) {
+                [delegate cdAudioSourceDidFinishPlaying:self];
+        }       
+}       
+
+-(void)audioPlayerBeginInterruption:(AVAudioPlayer *)player {
+        CDLOGINFO(@"Denshion::CDLongAudioSource - audio player interrupted");
+}
+
+-(void)audioPlayerEndInterruption:(AVAudioPlayer *)player {
+        CDLOGINFO(@"Denshion::CDLongAudioSource - audio player resumed");
+        if (self.backgroundMusic) {
+                //Check if background music can play as rules may have changed during 
+                //the interruption. This is to address a specific issue in 4.x when
+                //fast task switching
+                if([CDAudioManager sharedManager].willPlayBackgroundMusic) {
+                        [player play];
+                }       
+        } else {
+                [player play];
+        }       
+}       
+
+@end
+
+
+@interface CDAudioManager (PrivateMethods)
+-(BOOL) audioSessionSetActive:(BOOL) active;
+-(BOOL) audioSessionSetCategory:(NSString*) category;
+-(void) badAlContextHandler;
+@end
+
+
+@implementation CDAudioManager
+#define BACKGROUND_MUSIC_CHANNEL kASC_Left
+
+@synthesize soundEngine, willPlayBackgroundMusic;
+static CDAudioManager *sharedManager;
+static tAudioManagerState _sharedManagerState = kAMStateUninitialised;
+static tAudioManagerMode configuredMode;
+static BOOL configured = FALSE;
+
+-(BOOL) audioSessionSetActive:(BOOL) active {
+        NSError *activationError = nil;
+        if ([[AVAudioSession sharedInstance] setActive:active error:&activationError]) {
+                _audioSessionActive = active;
+                CDLOGINFO(@"Denshion::CDAudioManager - Audio session set active %i succeeded", active); 
+                return YES;
+        } else {
+                //Failed
+                CDLOG(@"Denshion::CDAudioManager - Audio session set active %i failed with error %@", active, activationError); 
+                return NO;
+        }       
+}       
+
+-(BOOL) audioSessionSetCategory:(NSString*) category {
+        NSError *categoryError = nil;
+        if ([[AVAudioSession sharedInstance] setCategory:category error:&categoryError]) {
+                CDLOGINFO(@"Denshion::CDAudioManager - Audio session set category %@ succeeded", category); 
+                return YES;
+        } else {
+                //Failed
+                CDLOG(@"Denshion::CDAudioManager - Audio session set category %@ failed with error %@", category, categoryError); 
+                return NO;
+        }       
+}       
+
+// Init
++ (CDAudioManager *) sharedManager
+{
+        @synchronized(self)     {
+                if (!sharedManager) {
+                        if (!configured) {
+                                //Set defaults here
+                                configuredMode = kAMM_FxPlusMusicIfNoOtherAudio;
+                        }
+                        sharedManager = [[CDAudioManager alloc] init:configuredMode];
+                        _sharedManagerState = kAMStateInitialised;//This is only really relevant when using asynchronous initialisation
+                        [[NSNotificationCenter defaultCenter] postNotificationName:kCDN_AudioManagerInitialised object:nil];
+                }       
+        }
+        return sharedManager;
+}
+
++ (tAudioManagerState) sharedManagerState {
+        return _sharedManagerState;
+}       
+
+/**
+ * Call this to set up audio manager asynchronously.  Initialisation is finished when sharedManagerState == kAMStateInitialised
+ */
++ (void) initAsynchronously: (tAudioManagerMode) mode {
+        @synchronized(self) {
+                if (_sharedManagerState == kAMStateUninitialised) {
+                        _sharedManagerState = kAMStateInitialising;
+                        [CDAudioManager configure:mode];
+                        CDAsynchInitialiser *initOp = [[[CDAsynchInitialiser alloc] init] autorelease];
+                        NSOperationQueue *opQ = [[[NSOperationQueue alloc] init] autorelease];
+                        [opQ addOperation:initOp];
+                }       
+        }
+}       
+
++ (id) alloc
+{
+        @synchronized(self)     {
+                NSAssert(sharedManager == nil, @"Attempted to allocate a second instance of a singleton.");
+                return [super alloc];
+        }
+        return nil;
+}
+
+/*
+ * Call this method before accessing the shared manager in order to configure the shared audio manager
+ */
++ (void) configure: (tAudioManagerMode) mode {
+        configuredMode = mode;
+        configured = TRUE;
+}       
+
+-(BOOL) isOtherAudioPlaying {
+        UInt32 isPlaying = 0;
+        UInt32 varSize = sizeof(isPlaying);
+        AudioSessionGetProperty (kAudioSessionProperty_OtherAudioIsPlaying, &varSize, &isPlaying);
+        return (isPlaying != 0);
+}
+
+-(void) setMode:(tAudioManagerMode) mode {
+
+        _mode = mode;
+        switch (_mode) {
+                        
+                case kAMM_FxOnly:
+                        //Share audio with other app
+                        CDLOGINFO(@"Denshion::CDAudioManager - Audio will be shared");
+                        //_audioSessionCategory = kAudioSessionCategory_AmbientSound;
+                        _audioSessionCategory = AVAudioSessionCategoryAmbient;
+                        willPlayBackgroundMusic = NO;
+                        break;
+                        
+                case kAMM_FxPlusMusic:
+                        //Use audio exclusively - if other audio is playing it will be stopped
+                        CDLOGINFO(@"Denshion::CDAudioManager -  Audio will be exclusive");
+                        //_audioSessionCategory = kAudioSessionCategory_SoloAmbientSound;
+                        _audioSessionCategory = AVAudioSessionCategorySoloAmbient;
+                        willPlayBackgroundMusic = YES;
+                        break;
+                        
+                case kAMM_MediaPlayback:
+                        //Use audio exclusively, ignore mute switch and sleep
+                        CDLOGINFO(@"Denshion::CDAudioManager -  Media playback mode, audio will be exclusive");
+                        //_audioSessionCategory = kAudioSessionCategory_MediaPlayback;
+                        _audioSessionCategory = AVAudioSessionCategoryPlayback;
+                        willPlayBackgroundMusic = YES;
+                        break;
+                        
+                case kAMM_PlayAndRecord:
+                        //Use audio exclusively, ignore mute switch and sleep, has inputs and outputs
+                        CDLOGINFO(@"Denshion::CDAudioManager -  Play and record mode, audio will be exclusive");
+                        //_audioSessionCategory = kAudioSessionCategory_PlayAndRecord;
+                        _audioSessionCategory = AVAudioSessionCategoryPlayAndRecord;
+                        willPlayBackgroundMusic = YES;
+                        break;
+                        
+                default:
+                        //kAudioManagerFxPlusMusicIfNoOtherAudio
+                        if ([self isOtherAudioPlaying]) {
+                                CDLOGINFO(@"Denshion::CDAudioManager - Other audio is playing audio will be shared");
+                                //_audioSessionCategory = kAudioSessionCategory_AmbientSound;
+                                _audioSessionCategory = AVAudioSessionCategoryAmbient;
+                                willPlayBackgroundMusic = NO;
+                        } else {
+                                CDLOGINFO(@"Denshion::CDAudioManager - Other audio is not playing audio will be exclusive");
+                                //_audioSessionCategory = kAudioSessionCategory_SoloAmbientSound;
+                                _audioSessionCategory = AVAudioSessionCategorySoloAmbient;
+                                willPlayBackgroundMusic = YES;
+                        }       
+                        
+                        break;
+        }
+         
+        [self audioSessionSetCategory:_audioSessionCategory];
+        
+}       
+
+/**
+ * This method is used to work around various bugs introduced in 4.x OS versions. In some circumstances the 
+ * audio session is interrupted but never resumed, this results in the loss of OpenAL audio when following 
+ * standard practices. If we detect this situation then we will attempt to resume the audio session ourselves.
+ * Known triggers: lock the device then unlock it (iOS 4.2 gm), playback a song using MPMediaPlayer (iOS 4.0)
+ */
+- (void) badAlContextHandler {
+        if (_interrupted && alcGetCurrentContext() == NULL) {
+                CDLOG(@"Denshion::CDAudioManager - bad OpenAL context detected, attempting to resume audio session");
+                [self audioSessionResumed];
+        }       
+}       
+
+- (id) init: (tAudioManagerMode) mode {
+        if ((self = [super init])) {
+                
+                //Initialise the audio session 
+                AVAudioSession* session = [AVAudioSession sharedInstance];
+                session.delegate = self;
+        
+                _mode = mode;
+                backgroundMusicCompletionSelector = nil;
+                _isObservingAppEvents = FALSE;
+                _mute = NO;
+                _resigned = NO;
+                _interrupted = NO;
+                enabled_ = YES;
+                _audioSessionActive = NO;
+                [self setMode:mode];
+                soundEngine = [[CDSoundEngine alloc] init];
+                
+                //Set up audioSource channels
+                audioSourceChannels = [[NSMutableArray alloc] init];
+                CDLongAudioSource *leftChannel = [[CDLongAudioSource alloc] init];
+                leftChannel.backgroundMusic = YES;
+                CDLongAudioSource *rightChannel = [[CDLongAudioSource alloc] init];
+                rightChannel.backgroundMusic = NO;
+                [audioSourceChannels insertObject:leftChannel atIndex:kASC_Left];       
+                [audioSourceChannels insertObject:rightChannel atIndex:kASC_Right];
+                [leftChannel release];
+                [rightChannel release];
+                //Used to support legacy APIs
+                backgroundMusic = [self audioSourceForChannel:BACKGROUND_MUSIC_CHANNEL];
+                backgroundMusic.delegate = self;
+                
+                //Add handler for bad al context messages, these are posted by the sound engine.
+                [[NSNotificationCenter defaultCenter] addObserver:self  selector:@selector(badAlContextHandler) name:kCDN_BadAlContext object:nil];
+
+        }       
+        return self;            
+}       
+
+-(void) dealloc {
+        CDLOGINFO(@"Denshion::CDAudioManager - deallocating");
+        [self stopBackgroundMusic];
+        [soundEngine release];
+        [[NSNotificationCenter defaultCenter] removeObserver:self];
+        [self audioSessionSetActive:NO];
+        [audioSourceChannels release];
+        [super dealloc];
+}       
+
+/** Retrieves the audio source for the specified channel */
+-(CDLongAudioSource*) audioSourceForChannel:(tAudioSourceChannel) channel 
+{
+        return (CDLongAudioSource*)[audioSourceChannels objectAtIndex:channel];
+}       
+
+/** Loads the data from the specified file path to the channel's audio source */
+-(CDLongAudioSource*) audioSourceLoad:(NSString*) filePath channel:(tAudioSourceChannel) channel
+{
+        CDLongAudioSource *audioSource = [self audioSourceForChannel:channel];
+        if (audioSource) {
+                [audioSource load:filePath];
+        }
+        return audioSource;
+}       
+
+-(BOOL) isBackgroundMusicPlaying {
+        return [self.backgroundMusic isPlaying];
+}       
+
+//NB: originally I tried using a route change listener and intended to store the current route,
+//however, on a 3gs running 3.1.2 no route change is generated when the user switches the 
+//ringer mute switch to off (i.e. enables sound) therefore polling is the only reliable way to
+//determine ringer switch state
+-(BOOL) isDeviceMuted {
+
+#if TARGET_IPHONE_SIMULATOR
+        //Calling audio route stuff on the simulator causes problems
+        return NO;
+#else   
+        CFStringRef newAudioRoute;
+        UInt32 propertySize = sizeof (CFStringRef);
+        
+        AudioSessionGetProperty (
+                                                         kAudioSessionProperty_AudioRoute,
+                                                         &propertySize,
+                                                         &newAudioRoute
+                                                         );
+        
+        if (newAudioRoute == NULL) {
+                //Don't expect this to happen but playing safe otherwise a null in the CFStringCompare will cause a crash
+                return YES;
+        } else {        
+                CFComparisonResult newDeviceIsMuted =   CFStringCompare (
+                                                                                                                                 newAudioRoute,
+                                                                                                                                 (CFStringRef) @"",
+                                                                                                                                 0
+                                                                                                                                 );
+                
+                return (newDeviceIsMuted == kCFCompareEqualTo);
+        }       
+#endif
+}       
+
+#pragma mark Audio Interrupt Protocol
+
+-(BOOL) mute {
+        return _mute;
+}       
+
+-(void) setMute:(BOOL) muteValue {
+        if (muteValue != _mute) {
+                _mute = muteValue;
+                [soundEngine setMute:muteValue];
+                for( CDLongAudioSource *audioSource in audioSourceChannels) {
+                        audioSource.mute = muteValue;
+                }       
+        }       
+}
+
+-(BOOL) enabled {
+        return enabled_;
+}       
+
+-(void) setEnabled:(BOOL) enabledValue {
+        if (enabledValue != enabled_) {
+                enabled_ = enabledValue;
+                [soundEngine setEnabled:enabled_];
+                for( CDLongAudioSource *audioSource in audioSourceChannels) {
+                        audioSource.enabled = enabled_;
+                }       
+        }       
+}
+
+-(CDLongAudioSource*) backgroundMusic
+{
+        return backgroundMusic;
+}       
+
+//Load background music ready for playing
+-(void) preloadBackgroundMusic:(NSString*) filePath
+{
+        [self.backgroundMusic load:filePath];   
+}       
+
+-(void) playBackgroundMusic:(NSString*) filePath loop:(BOOL) loop
+{
+        [self.backgroundMusic load:filePath];
+
+        if (!willPlayBackgroundMusic || _mute) {
+                CDLOGINFO(@"Denshion::CDAudioManager - play bgm aborted because audio is not exclusive or sound is muted");
+                return;
+        }
+                
+        if (loop) {
+                [self.backgroundMusic setNumberOfLoops:-1];
+        } else {
+                [self.backgroundMusic setNumberOfLoops:0];
+        }       
+        [self.backgroundMusic play];
+}
+
+-(void) stopBackgroundMusic
+{
+        [self.backgroundMusic stop];
+}
+
+-(void) pauseBackgroundMusic
+{
+        [self.backgroundMusic pause];
+}       
+
+-(void) resumeBackgroundMusic
+{
+        if (!willPlayBackgroundMusic || _mute) {
+                CDLOGINFO(@"Denshion::CDAudioManager - resume bgm aborted because audio is not exclusive or sound is muted");
+                return;
+        }
+        
+        [self.backgroundMusic resume];
+}       
+
+-(void) rewindBackgroundMusic
+{
+        [self.backgroundMusic rewind];
+}       
+
+-(void) setBackgroundMusicCompletionListener:(id) listener selector:(SEL) selector {
+        backgroundMusicCompletionListener = listener;
+        backgroundMusicCompletionSelector = selector;
+}       
+
+/*
+ * Call this method to have the audio manager automatically handle application resign and
+ * become active.  Pass a tAudioManagerResignBehavior to indicate the desired behavior
+ * for resigning and becoming active again.
+ *
+ * If autohandle is YES then the applicationWillResignActive and applicationDidBecomActive 
+ * methods are automatically called, otherwise you must call them yourself at the appropriate time.
+ *
+ * Based on idea of Dominique Bongard
+ */
+-(void) setResignBehavior:(tAudioManagerResignBehavior) resignBehavior autoHandle:(BOOL) autoHandle { 
+
+        if (!_isObservingAppEvents && autoHandle) {
+                [[NSNotificationCenter defaultCenter] addObserver:self  selector:@selector(applicationWillResignActive:) name:@"UIApplicationWillResignActiveNotification" object:nil];
+                [[NSNotificationCenter defaultCenter] addObserver:self  selector:@selector(applicationDidBecomeActive:) name:@"UIApplicationDidBecomeActiveNotification" object:nil];
+                [[NSNotificationCenter defaultCenter] addObserver:self  selector:@selector(applicationWillTerminate:) name:@"UIApplicationWillTerminateNotification" object:nil];
+                _isObservingAppEvents = TRUE;
+        }
+        _resignBehavior = resignBehavior;
+}       
+
+- (void) applicationWillResignActive {
+        self->_resigned = YES;
+        
+        //Set the audio sesssion to one that allows sharing so that other audio won't be clobbered on resume
+        [self audioSessionSetCategory:AVAudioSessionCategoryAmbient];
+        
+        switch (_resignBehavior) {
+                        
+                case kAMRBStopPlay:
+                        
+                        for( CDLongAudioSource *audioSource in audioSourceChannels) {
+                                if (audioSource.isPlaying) {
+                                        audioSource->systemPaused = YES;
+                                        audioSource->systemPauseLocation = audioSource.audioSourcePlayer.currentTime;
+                                        [audioSource stop];
+                                } else {
+                                        //Music is either paused or stopped, if it is paused it will be restarted
+                                        //by OS so we will stop it.
+                                        audioSource->systemPaused = NO;
+                                        [audioSource stop];
+                                }
+                        }
+                        break;
+                        
+                case kAMRBStop:
+                        //Stop music regardless of whether it is playing or not because if it was paused
+                        //then the OS would resume it
+                        for( CDLongAudioSource *audioSource in audioSourceChannels) {
+                                [audioSource stop];
+                        }       
+                        
+                default:
+                        break;
+                        
+        }                       
+        CDLOGINFO(@"Denshion::CDAudioManager - handled resign active");
+}
+
+//Called when application resigns active only if setResignBehavior has been called
+- (void) applicationWillResignActive:(NSNotification *) notification
+{
+        [self applicationWillResignActive];
+}       
+
+- (void) applicationDidBecomeActive {
+        
+        if (self->_resigned) {
+                _resigned = NO;
+                //Reset the mode incase something changed with audio while we were inactive
+                [self setMode:_mode];
+                switch (_resignBehavior) {
+                                
+                        case kAMRBStopPlay:
+                                
+                                //Music had been stopped but stop maintains current time
+                                //so playing again will continue from where music was before resign active.
+                                //We check if music can be played because while we were inactive the user might have
+                                //done something that should force music to not play such as starting a track in the iPod
+                                if (self.willPlayBackgroundMusic) {
+                                        for( CDLongAudioSource *audioSource in audioSourceChannels) {
+                                                if (audioSource->systemPaused) {
+                                                        [audioSource resume];
+                                                        audioSource->systemPaused = NO;
+                                                }
+                                        }
+                                }
+                                break;
+                                
+                        default:
+                                break;
+                                
+                }
+                CDLOGINFO(@"Denshion::CDAudioManager - audio manager handled become active");
+        }
+}
+
+//Called when application becomes active only if setResignBehavior has been called
+- (void) applicationDidBecomeActive:(NSNotification *) notification
+{
+        [self applicationDidBecomeActive];
+}
+
+//Called when application terminates only if setResignBehavior has been called 
+- (void) applicationWillTerminate:(NSNotification *) notification
+{
+        CDLOGINFO(@"Denshion::CDAudioManager - audio manager handling terminate");
+        [self stopBackgroundMusic];
+}
+
+/** The audio source completed playing */
+- (void) cdAudioSourceDidFinishPlaying:(CDLongAudioSource *) audioSource {
+        CDLOGINFO(@"Denshion::CDAudioManager - audio manager got told background music finished");
+        if (backgroundMusicCompletionSelector != nil) {
+                [backgroundMusicCompletionListener performSelector:backgroundMusicCompletionSelector];
+        }       
+}       
+
+-(void) beginInterruption {
+        CDLOGINFO(@"Denshion::CDAudioManager - begin interruption");
+        [self audioSessionInterrupted];
+}
+
+-(void) endInterruption {
+        CDLOGINFO(@"Denshion::CDAudioManager - end interruption");
+        [self audioSessionResumed];
+}
+
+#if __IPHONE_OS_VERSION_MAX_ALLOWED >= 40000
+-(void) endInterruptionWithFlags:(NSUInteger)flags {
+        CDLOGINFO(@"Denshion::CDAudioManager - interruption ended with flags %i",flags);
+        if (flags == AVAudioSessionInterruptionFlags_ShouldResume) {
+                [self audioSessionResumed];
+        }       
+}
+#endif
+
+-(void)audioSessionInterrupted 
+{ 
+    if (!_interrupted) {
+                CDLOGINFO(@"Denshion::CDAudioManager - Audio session interrupted"); 
+                _interrupted = YES;
+
+                // Deactivate the current audio session 
+            [self audioSessionSetActive:NO];
+                
+                if (alcGetCurrentContext() != NULL) {
+                        CDLOGINFO(@"Denshion::CDAudioManager - Setting OpenAL context to NULL"); 
+
+                        ALenum  error = AL_NO_ERROR;
+
+                        // set the current context to NULL will 'shutdown' openAL 
+                        alcMakeContextCurrent(NULL); 
+                
+                        if((error = alGetError()) != AL_NO_ERROR) {
+                                CDLOG(@"Denshion::CDAudioManager - Error making context current %x\n", error);
+                        } 
+                        #pragma unused(error)
+                }
+        }       
+} 
+
+-(void)audioSessionResumed 
+{ 
+        if (_interrupted) {
+                CDLOGINFO(@"Denshion::CDAudioManager - Audio session resumed"); 
+                _interrupted = NO;
+                
+                BOOL activationResult = NO;
+                // Reactivate the current audio session
+                activationResult = [self audioSessionSetActive:YES]; 
+                
+                //This code is to handle a problem with iOS 4.0 and 4.01 where reactivating the session can fail if
+                //task switching is performed too rapidly. A test case that reliably reproduces the issue is to call the
+                //iPhone and then hang up after two rings (timing may vary ;))
+                //Basically we keep waiting and trying to let the OS catch up with itself but the number of tries is
+                //limited.
+                if (!activationResult) {
+                        CDLOG(@"Denshion::CDAudioManager - Failure reactivating audio session, will try wait-try cycle"); 
+                        int activateCount = 0;
+                        while (!activationResult && activateCount < 10) {
+                                [NSThread sleepForTimeInterval:0.5];
+                                activationResult = [self audioSessionSetActive:YES]; 
+                                activateCount++;
+                                CDLOGINFO(@"Denshion::CDAudioManager - Reactivation attempt %i status = %i",activateCount,activationResult); 
+                        }       
+                }
+                
+                if (alcGetCurrentContext() == NULL) {
+                        CDLOGINFO(@"Denshion::CDAudioManager - Restoring OpenAL context"); 
+                        ALenum  error = AL_NO_ERROR;
+                        // Restore open al context 
+                        alcMakeContextCurrent([soundEngine openALContext]); 
+                        if((error = alGetError()) != AL_NO_ERROR) {
+                                CDLOG(@"Denshion::CDAudioManager - Error making context current%x\n", error);
+                        } 
+                        #pragma unused(error)
+                }       
+        }       
+}
+
++(void) end {
+        [sharedManager release];
+        sharedManager = nil;
+}       
+
+@end
+
+///////////////////////////////////////////////////////////////////////////////////////
+@implementation CDLongAudioSourceFader
+
+-(void) _setTargetProperty:(float) newVal {
+        ((CDLongAudioSource*)target).volume = newVal;
+}       
+
+-(float) _getTargetProperty {
+        return ((CDLongAudioSource*)target).volume;
+}
+
+-(void) _stopTarget {
+        //Pause instead of stop as stop releases resources and causes problems in the simulator
+        [((CDLongAudioSource*)target) pause];
+}
+
+-(Class) _allowableType {
+        return [CDLongAudioSource class];
+}       
+
+@end
+///////////////////////////////////////////////////////////////////////////////////////
+@implementation CDBufferManager
+
+-(id) initWithEngine:(CDSoundEngine *) theSoundEngine {
+        if ((self = [super init])) {
+                soundEngine = theSoundEngine;
+                loadedBuffers = [[NSMutableDictionary alloc] initWithCapacity:CD_BUFFERS_START];
+                freedBuffers = [[NSMutableArray alloc] init];
+                nextBufferId = 0;
+        }       
+        return self;
+}       
+
+-(void) dealloc {
+        [loadedBuffers release];
+        [freedBuffers release];
+        [super dealloc];
+}       
+
+-(int) bufferForFile:(NSString*) filePath create:(BOOL) create {
+        
+        NSNumber* soundId = (NSNumber*)[loadedBuffers objectForKey:filePath];
+        if(soundId == nil)
+        {
+                if (create) {
+                        NSNumber* bufferId = nil;
+                        //First try to get a buffer from the free buffers
+                        if ([freedBuffers count] > 0) {
+                                bufferId = [[[freedBuffers lastObject] retain] autorelease];
+                                [freedBuffers removeLastObject]; 
+                                CDLOGINFO(@"Denshion::CDBufferManager reusing buffer id %i",[bufferId intValue]);
+                        } else {
+                                bufferId = [[NSNumber alloc] initWithInt:nextBufferId];
+                                [bufferId autorelease];
+                                CDLOGINFO(@"Denshion::CDBufferManager generating new buffer id %i",[bufferId intValue]);
+                                nextBufferId++;
+                        }
+                        
+                        if ([soundEngine loadBuffer:[bufferId intValue] filePath:filePath]) {
+                                //File successfully loaded
+                                CDLOGINFO(@"Denshion::CDBufferManager buffer loaded %@ %@",bufferId,filePath);
+                                [loadedBuffers setObject:bufferId forKey:filePath];
+                                return [bufferId intValue];
+                        } else {
+                                //File didn't load, put buffer id on free list
+                                [freedBuffers addObject:bufferId];
+                                return kCDNoBuffer;
+                        }       
+                } else {
+                        //No matching buffer was found
+                        return kCDNoBuffer;
+                }       
+        } else {
+                return [soundId intValue];
+        }       
+}       
+
+-(void) releaseBufferForFile:(NSString *) filePath {
+        int bufferId = [self bufferForFile:filePath create:NO];
+        if (bufferId != kCDNoBuffer) {
+                [soundEngine unloadBuffer:bufferId];
+                [loadedBuffers removeObjectForKey:filePath];
+                NSNumber *freedBufferId = [[NSNumber alloc] initWithInt:bufferId];
+                [freedBufferId autorelease];
+                [freedBuffers addObject:freedBufferId];
+        }       
+}       
+@end
+
+
+