Initial commit (version 0.2.1)

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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 "CocosDenshion.h"
+
+ALvoid  alBufferDataStaticProc(const ALint bid, ALenum format, ALvoid* data, ALsizei size, ALsizei freq);
+ALvoid  alcMacOSXMixerOutputRateProc(const ALdouble value);
+
+
+typedef ALvoid  AL_APIENTRY     (*alBufferDataStaticProcPtr) (const ALint bid, ALenum format, ALvoid* data, ALsizei size, ALsizei freq);
+ALvoid  alBufferDataStaticProc(const ALint bid, ALenum format, ALvoid* data, ALsizei size, ALsizei freq)
+{
+        static  alBufferDataStaticProcPtr       proc = NULL;
+    
+    if (proc == NULL) {
+        proc = (alBufferDataStaticProcPtr) alcGetProcAddress(NULL, (const ALCchar*) "alBufferDataStatic");
+    }
+    
+    if (proc)
+        proc(bid, format, data, size, freq);
+        
+    return;
+}
+
+typedef ALvoid  AL_APIENTRY     (*alcMacOSXMixerOutputRateProcPtr) (const ALdouble value);
+ALvoid  alcMacOSXMixerOutputRateProc(const ALdouble value)
+{
+        static  alcMacOSXMixerOutputRateProcPtr proc = NULL;
+    
+    if (proc == NULL) {
+        proc = (alcMacOSXMixerOutputRateProcPtr) alcGetProcAddress(NULL, (const ALCchar*) "alcMacOSXMixerOutputRate");
+    }
+    
+    if (proc)
+        proc(value);
+        
+    return;
+}
+
+NSString * const kCDN_BadAlContext = @"kCDN_BadAlContext";
+NSString * const kCDN_AsynchLoadComplete = @"kCDN_AsynchLoadComplete";
+float const kCD_PitchDefault = 1.0f;
+float const kCD_PitchLowerOneOctave = 0.5f;
+float const kCD_PitchHigherOneOctave = 2.0f;
+float const kCD_PanDefault = 0.0f;
+float const kCD_PanFullLeft = -1.0f;
+float const kCD_PanFullRight = 1.0f;
+float const kCD_GainDefault = 1.0f;
+
+@interface CDSoundEngine (PrivateMethods)
+-(BOOL) _initOpenAL;
+-(void) _testGetGain;
+-(void) _dumpSourceGroupsInfo;
+-(void) _getSourceIndexForSourceGroup;
+-(void) _freeSourceGroups;
+-(BOOL) _setUpSourceGroups:(int[]) definitions total:(NSUInteger) total; 
+@end
+
+#pragma mark -
+#pragma mark CDUtilities
+
+@implementation CDUtilities
+
++(NSString*) fullPathFromRelativePath:(NSString*) relPath
+{
+        // do not convert an absolute path (starting with '/')
+        if(([relPath length] > 0) && ([relPath characterAtIndex:0] == '/'))
+        {
+                return relPath;
+        }
+        
+        NSMutableArray *imagePathComponents = [NSMutableArray arrayWithArray:[relPath pathComponents]];
+        NSString *file = [imagePathComponents lastObject];
+        
+        [imagePathComponents removeLastObject];
+        NSString *imageDirectory = [NSString pathWithComponents:imagePathComponents];
+        
+        NSString *fullpath = [[NSBundle mainBundle] pathForResource:file ofType:nil inDirectory:imageDirectory];
+        if (fullpath == nil)
+                fullpath = relPath;
+        
+        return fullpath;        
+}
+
+@end
+
+#pragma mark -
+#pragma mark CDSoundEngine
+
+@implementation CDSoundEngine
+
+static Float32 _mixerSampleRate;
+static BOOL _mixerRateSet = NO;
+
+@synthesize lastErrorCode = lastErrorCode_;
+@synthesize functioning = functioning_;
+@synthesize asynchLoadProgress = asynchLoadProgress_;
+@synthesize getGainWorks = getGainWorks_;
+@synthesize sourceTotal = sourceTotal_;
+
++ (void) setMixerSampleRate:(Float32) sampleRate {
+        _mixerRateSet = YES;
+        _mixerSampleRate = sampleRate;
+}       
+
+- (void) _testGetGain {
+        float testValue = 0.7f;
+        ALuint testSourceId = _sources[0].sourceId;
+        alSourcef(testSourceId, AL_GAIN, 0.0f);//Start from know value
+        alSourcef(testSourceId, AL_GAIN, testValue);
+        ALfloat gainVal;
+        alGetSourcef(testSourceId, AL_GAIN, &gainVal);
+        getGainWorks_ = (gainVal == testValue);
+}
+
+//Generate sources one at a time until we fail
+-(void) _generateSources {
+        
+        _sources = (sourceInfo*)malloc( sizeof(_sources[0]) * CD_SOURCE_LIMIT);
+        BOOL hasFailed = NO;
+        sourceTotal_ = 0;
+        alGetError();//Clear error
+        while (!hasFailed && sourceTotal_ < CD_SOURCE_LIMIT) {
+                alGenSources(1, &(_sources[sourceTotal_].sourceId));
+                if (alGetError() == AL_NO_ERROR) {
+                        //Now try attaching source to null buffer
+                        alSourcei(_sources[sourceTotal_].sourceId, AL_BUFFER, 0);
+                        if (alGetError() == AL_NO_ERROR) {
+                                _sources[sourceTotal_].usable = true;   
+                                sourceTotal_++;
+                        } else {
+                                hasFailed = YES;
+                        }       
+                } else {
+                        _sources[sourceTotal_].usable = false;
+                        hasFailed = YES;
+                }       
+        }
+        //Mark the rest of the sources as not usable
+        for (int i=sourceTotal_; i < CD_SOURCE_LIMIT; i++) {
+                _sources[i].usable = false;
+        }       
+}       
+
+-(void) _generateBuffers:(int) startIndex endIndex:(int) endIndex {
+        if (_buffers) {
+                alGetError();
+                for (int i=startIndex; i <= endIndex; i++) {
+                        alGenBuffers(1, &_buffers[i].bufferId);
+                        _buffers[i].bufferData = NULL;
+                        if (alGetError() == AL_NO_ERROR) {
+                                _buffers[i].bufferState = CD_BS_EMPTY;
+                        } else {
+                                _buffers[i].bufferState = CD_BS_FAILED;
+                                CDLOG(@"Denshion::CDSoundEngine - buffer creation failed %i",i);
+                        }       
+                }
+        }       
+}
+
+/**
+ * Internal method called during init
+ */
+- (BOOL) _initOpenAL
+{
+        //ALenum                        error;
+        context = NULL;
+        ALCdevice               *newDevice = NULL;
+
+        //Set the mixer rate for the audio mixer
+        if (!_mixerRateSet) {
+                _mixerSampleRate = CD_SAMPLE_RATE_DEFAULT;
+        }
+        alcMacOSXMixerOutputRateProc(_mixerSampleRate);
+        CDLOGINFO(@"Denshion::CDSoundEngine - mixer output rate set to %0.2f",_mixerSampleRate);
+        
+        // Create a new OpenAL Device
+        // Pass NULL to specify the system's default output device
+        newDevice = alcOpenDevice(NULL);
+        if (newDevice != NULL)
+        {
+                // Create a new OpenAL Context
+                // The new context will render to the OpenAL Device just created 
+                context = alcCreateContext(newDevice, 0);
+                if (context != NULL)
+                {
+                        // Make the new context the Current OpenAL Context
+                        alcMakeContextCurrent(context);
+                        
+                        // Create some OpenAL Buffer Objects
+                        [self _generateBuffers:0 endIndex:bufferTotal-1];
+                        
+                        // Create some OpenAL Source Objects
+                        [self _generateSources];
+                        
+                }
+        } else {
+                return FALSE;//No device
+        }       
+        alGetError();//Clear error
+        return TRUE;
+}
+
+- (void) dealloc {
+        
+        ALCcontext      *currentContext = NULL;
+    ALCdevice   *device = NULL;
+        
+        [self stopAllSounds];
+
+        CDLOGINFO(@"Denshion::CDSoundEngine - Deallocing sound engine.");
+        [self _freeSourceGroups];
+        
+        // Delete the Sources
+        CDLOGINFO(@"Denshion::CDSoundEngine - deleting sources.");
+        for (int i=0; i < sourceTotal_; i++) {
+                alSourcei(_sources[i].sourceId, AL_BUFFER, 0);//Detach from current buffer
+            alDeleteSources(1, &(_sources[i].sourceId));
+                if((lastErrorCode_ = alGetError()) != AL_NO_ERROR) {
+                        CDLOG(@"Denshion::CDSoundEngine - Error deleting source! %x\n", lastErrorCode_);
+                } 
+        }       
+
+        // Delete the Buffers
+        CDLOGINFO(@"Denshion::CDSoundEngine - deleting buffers.");
+        for (int i=0; i < bufferTotal; i++) {
+                alDeleteBuffers(1, &_buffers[i].bufferId);
+#ifdef CD_USE_STATIC_BUFFERS
+                if (_buffers[i].bufferData) {
+                        free(_buffers[i].bufferData);
+                }       
+#endif          
+        }       
+        CDLOGINFO(@"Denshion::CDSoundEngine - free buffers.");
+        free(_buffers);
+    currentContext = alcGetCurrentContext();
+    //Get device for active context
+    device = alcGetContextsDevice(currentContext);
+    //Release context
+        CDLOGINFO(@"Denshion::CDSoundEngine - destroy context.");
+    alcDestroyContext(currentContext);
+    //Close device
+        CDLOGINFO(@"Denshion::CDSoundEngine - close device.");
+    alcCloseDevice(device);
+        CDLOGINFO(@"Denshion::CDSoundEngine - free sources.");
+        free(_sources);
+        
+        //Release mutexes
+        [_mutexBufferLoad release];
+        
+        [super dealloc];
+}       
+
+-(NSUInteger) sourceGroupTotal {
+        return _sourceGroupTotal;
+}       
+
+-(void) _freeSourceGroups 
+{
+        CDLOGINFO(@"Denshion::CDSoundEngine freeing source groups");
+        if(_sourceGroups) {
+                for (int i=0; i < _sourceGroupTotal; i++) {
+                        if (_sourceGroups[i].sourceStatuses) {
+                                free(_sourceGroups[i].sourceStatuses);
+                                CDLOGINFO(@"Denshion::CDSoundEngine freed source statuses %i",i);
+                        }       
+                }
+                free(_sourceGroups);
+        }       
+}       
+
+-(BOOL) _redefineSourceGroups:(int[]) definitions total:(NSUInteger) total
+{
+        if (_sourceGroups) {
+                //Stop all sounds
+                [self stopAllSounds];
+                //Need to free source groups
+                [self _freeSourceGroups];
+        }
+        return [self _setUpSourceGroups:definitions total:total];
+}       
+
+-(BOOL) _setUpSourceGroups:(int[]) definitions total:(NSUInteger) total 
+{
+        _sourceGroups = (sourceGroup *)malloc( sizeof(_sourceGroups[0]) * total);
+        if(!_sourceGroups) {
+                CDLOG(@"Denshion::CDSoundEngine - source groups memory allocation failed");
+                return NO;
+        }
+        
+        _sourceGroupTotal = total;
+        int sourceCount = 0;
+        for (int i=0; i < _sourceGroupTotal; i++) {
+                
+                _sourceGroups[i].startIndex = 0;
+                _sourceGroups[i].currentIndex = _sourceGroups[i].startIndex;
+                _sourceGroups[i].enabled = false;
+                _sourceGroups[i].nonInterruptible = false;
+                _sourceGroups[i].totalSources = definitions[i];
+                _sourceGroups[i].sourceStatuses = malloc(sizeof(_sourceGroups[i].sourceStatuses[0]) * _sourceGroups[i].totalSources);
+                if (_sourceGroups[i].sourceStatuses) {
+                        for (int j=0; j < _sourceGroups[i].totalSources; j++) {
+                                //First bit is used to indicate whether source is locked, index is shifted back 1 bit
+                                _sourceGroups[i].sourceStatuses[j] = (sourceCount + j) << 1;    
+                        }       
+                }       
+                sourceCount += definitions[i];
+        }
+        return YES;
+}
+
+-(void) defineSourceGroups:(int[]) sourceGroupDefinitions total:(NSUInteger) total {
+        [self _redefineSourceGroups:sourceGroupDefinitions total:total];
+}
+
+-(void) defineSourceGroups:(NSArray*) sourceGroupDefinitions {
+        CDLOGINFO(@"Denshion::CDSoundEngine - source groups defined by NSArray.");
+        NSUInteger totalDefs = [sourceGroupDefinitions count];
+        int* defs = (int *)malloc( sizeof(int) * totalDefs);
+        int currentIndex = 0;
+        for (id currentDef in sourceGroupDefinitions) {
+                if ([currentDef isKindOfClass:[NSNumber class]]) {
+                        defs[currentIndex] = (int)[(NSNumber*)currentDef integerValue];
+                        CDLOGINFO(@"Denshion::CDSoundEngine - found definition %i.",defs[currentIndex]);
+                } else {
+                        CDLOG(@"Denshion::CDSoundEngine - warning, did not understand source definition.");
+                        defs[currentIndex] = 0;
+                }       
+                currentIndex++;
+        }
+        [self _redefineSourceGroups:defs total:totalDefs];
+        free(defs);
+}       
+
+- (id)init
+{       
+        if ((self = [super init])) {
+                
+                //Create mutexes
+                _mutexBufferLoad = [[NSObject alloc] init];
+                
+                asynchLoadProgress_ = 0.0f;
+                
+                bufferTotal = CD_BUFFERS_START;
+                _buffers = (bufferInfo *)malloc( sizeof(_buffers[0]) * bufferTotal);
+        
+                // Initialize our OpenAL environment
+                if ([self _initOpenAL]) {
+                        //Set up the default source group - a single group that contains all the sources
+                        int sourceDefs[1];
+                        sourceDefs[0] = self.sourceTotal;
+                        [self _setUpSourceGroups:sourceDefs total:1];
+
+                        functioning_ = YES;
+                        //Synchronize premute gain
+                        _preMuteGain = self.masterGain;
+                        mute_ = NO;
+                        enabled_ = YES;
+                        //Test whether get gain works for sources
+                        [self _testGetGain];
+                } else {
+                        //Something went wrong with OpenAL
+                        functioning_ = NO;
+                }
+        }
+        
+        return self;
+}
+
+/**
+ * Delete the buffer identified by soundId
+ * @return true if buffer deleted successfully, otherwise false
+ */
+- (BOOL) unloadBuffer:(int) soundId 
+{
+        //Ensure soundId is within array bounds otherwise memory corruption will occur
+        if (soundId < 0 || soundId >= bufferTotal) {
+                CDLOG(@"Denshion::CDSoundEngine - soundId is outside array bounds, maybe you need to increase CD_MAX_BUFFERS");
+                return FALSE;
+        }       
+        
+        //Before a buffer can be deleted any sources that are attached to it must be stopped
+        for (int i=0; i < sourceTotal_; i++) {
+                //Note: tried getting the AL_BUFFER attribute of the source instead but doesn't
+                //appear to work on a device - just returned zero.
+                if (_buffers[soundId].bufferId == _sources[i].attachedBufferId) {
+                        
+                        CDLOG(@"Denshion::CDSoundEngine - Found attached source %i %i %i",i,_buffers[soundId].bufferId,_sources[i].sourceId);
+#ifdef CD_USE_STATIC_BUFFERS
+                        //When using static buffers a crash may occur if a source is playing with a buffer that is about
+                        //to be deleted even though we stop the source and successfully delete the buffer. Crash is confirmed
+                        //on 2.2.1 and 3.1.2, however, it will only occur if a source is used rapidly after having its prior
+                        //data deleted. To avoid any possibility of the crash we wait for the source to finish playing.
+                        ALint state;
+                        
+                        alGetSourcei(_sources[i].sourceId, AL_SOURCE_STATE, &state);
+                        
+                        if (state == AL_PLAYING) {
+                                CDLOG(@"Denshion::CDSoundEngine - waiting for source to complete playing before removing buffer data"); 
+                                alSourcei(_sources[i].sourceId, AL_LOOPING, FALSE);//Turn off looping otherwise loops will never end
+                                while (state == AL_PLAYING) {
+                                        alGetSourcei(_sources[i].sourceId, AL_SOURCE_STATE, &state);
+                                        usleep(10000);
+                                }
+                        }
+#endif                  
+                        //Stop source and detach
+                        alSourceStop(_sources[i].sourceId);     
+                        if((lastErrorCode_ = alGetError()) != AL_NO_ERROR) {
+                                CDLOG(@"Denshion::CDSoundEngine - error stopping source: %x\n", lastErrorCode_);
+                        }       
+                        
+                        alSourcei(_sources[i].sourceId, AL_BUFFER, 0);//Attach to "NULL" buffer to detach
+                        if((lastErrorCode_ = alGetError()) != AL_NO_ERROR) {
+                                CDLOG(@"Denshion::CDSoundEngine - error detaching buffer: %x\n", lastErrorCode_);
+                        } else {
+                                //Record that source is now attached to nothing
+                                _sources[i].attachedBufferId = 0;
+                        }       
+                }       
+        }       
+        
+        alDeleteBuffers(1, &_buffers[soundId].bufferId);
+        if((lastErrorCode_ = alGetError()) != AL_NO_ERROR) {
+                CDLOG(@"Denshion::CDSoundEngine - error deleting buffer: %x\n", lastErrorCode_);
+                _buffers[soundId].bufferState = CD_BS_FAILED;
+                return FALSE;
+        } else {
+#ifdef CD_USE_STATIC_BUFFERS
+                //Free previous data, if alDeleteBuffer has returned without error then no 
+                if (_buffers[soundId].bufferData) {
+                        CDLOGINFO(@"Denshion::CDSoundEngine - freeing static data for soundId %i @ %i",soundId,_buffers[soundId].bufferData);
+                        free(_buffers[soundId].bufferData);//Free the old data
+                        _buffers[soundId].bufferData = NULL;
+                }
+#endif          
+        }       
+        
+        alGenBuffers(1, &_buffers[soundId].bufferId);
+        if((lastErrorCode_ = alGetError()) != AL_NO_ERROR) {
+                CDLOG(@"Denshion::CDSoundEngine - error regenerating buffer: %x\n", lastErrorCode_);
+                _buffers[soundId].bufferState = CD_BS_FAILED;
+                return FALSE;
+        } else {
+                //We now have an empty buffer
+                _buffers[soundId].bufferState = CD_BS_EMPTY;
+                CDLOGINFO(@"Denshion::CDSoundEngine - buffer %i successfully unloaded\n",soundId);
+                return TRUE;
+        }       
+}       
+
+/**
+ * Load buffers asynchronously 
+ * Check asynchLoadProgress for progress. asynchLoadProgress represents fraction of completion. When it equals 1.0 loading
+ * is complete. NB: asynchLoadProgress is simply based on the number of load requests, it does not take into account
+ * file sizes.
+ * @param An array of CDBufferLoadRequest objects
+ */
+- (void) loadBuffersAsynchronously:(NSArray *) loadRequests {
+        @synchronized(self) {
+                asynchLoadProgress_ = 0.0f;
+                CDAsynchBufferLoader *loaderOp = [[[CDAsynchBufferLoader alloc] init:loadRequests soundEngine:self] autorelease];
+                NSOperationQueue *opQ = [[[NSOperationQueue alloc] init] autorelease];
+                [opQ addOperation:loaderOp];
+        }
+}       
+
+-(BOOL) _resizeBuffers:(int) increment {
+        
+        void * tmpBufferInfos = realloc( _buffers, sizeof(_buffers[0]) * (bufferTotal + increment) );
+        
+        if(!tmpBufferInfos) {
+                free(tmpBufferInfos);
+                return NO;
+        } else {
+                _buffers = tmpBufferInfos;
+                int oldBufferTotal = bufferTotal;
+                bufferTotal = bufferTotal + increment;
+                [self _generateBuffers:oldBufferTotal endIndex:bufferTotal-1];
+                return YES;
+        }       
+}       
+
+-(BOOL) loadBufferFromData:(int) soundId soundData:(ALvoid*) soundData format:(ALenum) format size:(ALsizei) size freq:(ALsizei) freq {
+
+        @synchronized(_mutexBufferLoad) {
+                
+                if (!functioning_) {
+                        //OpenAL initialisation has previously failed
+                        CDLOG(@"Denshion::CDSoundEngine - Loading buffer failed because sound engine state != functioning");
+                        return FALSE;
+                }
+                
+                //Ensure soundId is within array bounds otherwise memory corruption will occur
+                if (soundId < 0) {
+                        CDLOG(@"Denshion::CDSoundEngine - soundId is negative");
+                        return FALSE;
+                }
+                
+                if (soundId >= bufferTotal) {
+                        //Need to resize the buffers
+                        int requiredIncrement = CD_BUFFERS_INCREMENT;
+                        while (bufferTotal + requiredIncrement < soundId) {
+                                requiredIncrement += CD_BUFFERS_INCREMENT;
+                        }
+                        CDLOGINFO(@"Denshion::CDSoundEngine - attempting to resize buffers by %i for sound %i",requiredIncrement,soundId);
+                        if (![self _resizeBuffers:requiredIncrement]) {
+                                CDLOG(@"Denshion::CDSoundEngine - buffer resize failed");
+                                return FALSE;
+                        }       
+                }       
+                
+                if (soundData)
+                {
+                        if (_buffers[soundId].bufferState != CD_BS_EMPTY) {
+                                CDLOGINFO(@"Denshion::CDSoundEngine - non empty buffer, regenerating");
+                                if (![self unloadBuffer:soundId]) {
+                                        //Deletion of buffer failed, delete buffer routine has set buffer state and lastErrorCode
+                                        return NO;
+                                }       
+                        }       
+                        
+#ifdef CD_DEBUG
+                        //Check that sample rate matches mixer rate and warn if they do not
+                        if (freq != (int)_mixerSampleRate) {
+                                CDLOGINFO(@"Denshion::CDSoundEngine - WARNING sample rate does not match mixer sample rate performance may not be optimal.");
+                        }       
+#endif          
+                        
+#ifdef CD_USE_STATIC_BUFFERS
+                        alBufferDataStaticProc(_buffers[soundId].bufferId, format, soundData, size, freq);
+                        _buffers[soundId].bufferData = data;//Save the pointer to the new data
+#else           
+                        alBufferData(_buffers[soundId].bufferId, format, soundData, size, freq);
+#endif
+                        if((lastErrorCode_ = alGetError()) != AL_NO_ERROR) {
+                                CDLOG(@"Denshion::CDSoundEngine -  error attaching audio to buffer: %x", lastErrorCode_);
+                                _buffers[soundId].bufferState = CD_BS_FAILED;
+                                return FALSE;
+                        } 
+                } else {
+                        CDLOG(@"Denshion::CDSoundEngine Buffer data is null!");
+                        _buffers[soundId].bufferState = CD_BS_FAILED;
+                        return FALSE;
+                }       
+                
+                _buffers[soundId].format = format;
+                _buffers[soundId].sizeInBytes = size;
+                _buffers[soundId].frequencyInHertz = freq;
+                _buffers[soundId].bufferState = CD_BS_LOADED;
+                CDLOGINFO(@"Denshion::CDSoundEngine Buffer %i loaded format:%i freq:%i size:%i",soundId,format,freq,size);
+                return TRUE;
+        }//end mutex
+}       
+
+/**
+ * Load sound data for later play back.
+ * @return TRUE if buffer loaded okay for play back otherwise false
+ */
+- (BOOL) loadBuffer:(int) soundId filePath:(NSString*) filePath
+{
+
+        ALvoid* data;
+        ALenum  format;
+        ALsizei size;
+        ALsizei freq;
+        
+        CDLOGINFO(@"Denshion::CDSoundEngine - Loading openAL buffer %i %@", soundId, filePath);
+        
+        CFURLRef fileURL = nil;
+        NSString *path = [CDUtilities fullPathFromRelativePath:filePath];
+        if (path) {
+                fileURL = (CFURLRef)[[NSURL fileURLWithPath:path] retain];
+        }
+
+        if (fileURL)
+        {
+                data = CDGetOpenALAudioData(fileURL, &size, &format, &freq);
+                CFRelease(fileURL);
+                BOOL result = [self loadBufferFromData:soundId soundData:data format:format size:size freq:freq];
+#ifndef CD_USE_STATIC_BUFFERS
+                free(data);//Data can be freed here because alBufferData performs a memcpy              
+#endif
+                return result;
+        } else {
+                CDLOG(@"Denshion::CDSoundEngine Could not find file!\n");
+                //Don't change buffer state here as it will be the same as before method was called     
+                return FALSE;
+        }       
+}
+
+-(BOOL) validateBufferId:(int) soundId {
+        if (soundId < 0 || soundId >= bufferTotal) {
+                CDLOGINFO(@"Denshion::CDSoundEngine - validateBufferId buffer outside range %i",soundId);
+                return NO;
+        } else if (_buffers[soundId].bufferState != CD_BS_LOADED) {
+                CDLOGINFO(@"Denshion::CDSoundEngine - validateBufferId invalide buffer state %i",soundId);
+                return NO;
+        } else {
+                return YES;
+        }       
+}       
+
+-(float) bufferDurationInSeconds:(int) soundId {
+        if ([self validateBufferId:soundId]) {
+                float factor = 0.0f;
+                switch (_buffers[soundId].format) {
+                        case AL_FORMAT_MONO8:
+                                factor = 1.0f;
+                                break;
+                        case AL_FORMAT_MONO16:
+                                factor = 0.5f;
+                                break;
+                        case AL_FORMAT_STEREO8:
+                                factor = 0.5f;
+                                break;
+                        case AL_FORMAT_STEREO16:
+                                factor = 0.25f;
+                                break;
+                }       
+                return (float)_buffers[soundId].sizeInBytes/(float)_buffers[soundId].frequencyInHertz * factor;
+        } else {
+                return -1.0f;
+        }       
+}       
+
+-(ALsizei) bufferSizeInBytes:(int) soundId {
+        if ([self validateBufferId:soundId]) {
+                return _buffers[soundId].sizeInBytes;
+        } else {
+                return -1.0f;
+        }       
+}       
+
+-(ALsizei) bufferFrequencyInHertz:(int) soundId {
+        if ([self validateBufferId:soundId]) {
+                return _buffers[soundId].frequencyInHertz;
+        } else {
+                return -1.0f;
+        }       
+}       
+
+- (ALfloat) masterGain {
+        if (mute_) {
+                //When mute the real gain will always be 0 therefore return the preMuteGain value
+                return _preMuteGain;
+        } else {        
+                ALfloat gain;
+                alGetListenerf(AL_GAIN, &gain);
+                return gain;
+        }       
+}       
+
+/**
+ * Overall gain setting multiplier. e.g 0.5 is half the gain.
+ */
+- (void) setMasterGain:(ALfloat) newGainValue {
+        if (mute_) {
+                _preMuteGain = newGainValue;
+        } else {        
+                alListenerf(AL_GAIN, newGainValue);
+        }       
+}
+
+#pragma mark CDSoundEngine AudioInterrupt protocol
+- (BOOL) mute {
+        return mute_;
+}       
+
+/**
+ * Setting mute silences all sounds but playing sounds continue to advance playback
+ */
+- (void) setMute:(BOOL) newMuteValue {
+        
+        if (newMuteValue == mute_) {
+                return;
+        }
+        
+        mute_ = newMuteValue;
+        if (mute_) {
+                //Remember what the gain was
+                _preMuteGain = self.masterGain;
+                //Set gain to 0 - do not use the property as this will adjust preMuteGain when muted
+                alListenerf(AL_GAIN, 0.0f);
+        } else {
+                //Restore gain to what it was before being muted
+                self.masterGain = _preMuteGain;
+        }       
+}
+
+- (BOOL) enabled {
+        return enabled_;
+}
+
+- (void) setEnabled:(BOOL)enabledValue
+{
+        if (enabled_ == enabledValue) {
+                return;
+        }       
+        enabled_ = enabledValue;
+        if (enabled_ == NO) {
+                [self stopAllSounds];
+        }       
+}       
+
+-(void) _lockSource:(int) sourceIndex lock:(BOOL) lock {
+        BOOL found = NO;
+        for (int i=0; i < _sourceGroupTotal && !found; i++) {
+                if (_sourceGroups[i].sourceStatuses) {
+                        for (int j=0; j < _sourceGroups[i].totalSources && !found; j++) {
+                                //First bit is used to indicate whether source is locked, index is shifted back 1 bit
+                                if((_sourceGroups[i].sourceStatuses[j] >> 1)==sourceIndex) {
+                                        if (lock) {
+                                                //Set first bit to lock this source
+                                                _sourceGroups[i].sourceStatuses[j] |= 1;
+                                        } else {
+                                                //Unset first bit to unlock this source
+                                                _sourceGroups[i].sourceStatuses[j] &= ~1; 
+                                        }       
+                                        found = YES;
+                                }       
+                        }       
+                }       
+        }
+}       
+
+-(int) _getSourceIndexForSourceGroup:(int)sourceGroupId 
+{
+        //Ensure source group id is valid to prevent memory corruption
+        if (sourceGroupId < 0 || sourceGroupId >= _sourceGroupTotal) {
+                CDLOG(@"Denshion::CDSoundEngine invalid source group id %i",sourceGroupId);
+                return CD_NO_SOURCE;
+        }       
+
+        int sourceIndex = -1;//Using -1 to indicate no source found
+        BOOL complete = NO;
+        ALint sourceState = 0;
+        sourceGroup *thisSourceGroup = &_sourceGroups[sourceGroupId];
+        thisSourceGroup->currentIndex = thisSourceGroup->startIndex;
+        while (!complete) {
+                //Iterate over sources looking for one that is not locked, first bit indicates if source is locked
+                if ((thisSourceGroup->sourceStatuses[thisSourceGroup->currentIndex] & 1) == 0) {
+                        //This source is not locked
+                        sourceIndex = thisSourceGroup->sourceStatuses[thisSourceGroup->currentIndex] >> 1;//shift back to get the index
+                        if (thisSourceGroup->nonInterruptible) {
+                                //Check if this source is playing, if so it can't be interrupted
+                                alGetSourcei(_sources[sourceIndex].sourceId, AL_SOURCE_STATE, &sourceState);
+                                if (sourceState != AL_PLAYING) {
+                                        //complete = YES;
+                                        //Set start index so next search starts at the next position
+                                        thisSourceGroup->startIndex = thisSourceGroup->currentIndex + 1;
+                                        break;
+                                } else {
+                                        sourceIndex = -1;//The source index was no good because the source was playing
+                                }       
+                        } else {        
+                                //complete = YES;
+                                //Set start index so next search starts at the next position
+                                thisSourceGroup->startIndex = thisSourceGroup->currentIndex + 1;
+                                break;
+                        }       
+                }
+                thisSourceGroup->currentIndex++;
+                if (thisSourceGroup->currentIndex >= thisSourceGroup->totalSources) {
+                        //Reset to the beginning
+                        thisSourceGroup->currentIndex = 0;      
+                }       
+                if (thisSourceGroup->currentIndex == thisSourceGroup->startIndex) {
+                        //We have looped around and got back to the start
+                        complete = YES;
+                }       
+        }
+
+        //Reset start index to beginning if beyond bounds
+        if (thisSourceGroup->startIndex >= thisSourceGroup->totalSources) {
+                thisSourceGroup->startIndex = 0;        
+        }       
+        
+        if (sourceIndex >= 0) {
+                return sourceIndex;
+        } else {        
+                return CD_NO_SOURCE;
+        }       
+        
+}       
+
+/**
+ * Play a sound.
+ * @param soundId the id of the sound to play (buffer id).
+ * @param SourceGroupId the source group that will be used to play the sound.
+ * @param pitch pitch multiplier. e.g 1.0 is unaltered, 0.5 is 1 octave lower. 
+ * @param pan stereo position. -1 is fully left, 0 is centre and 1 is fully right.
+ * @param gain gain multiplier. e.g. 1.0 is unaltered, 0.5 is half the gain
+ * @param loop should the sound be looped or one shot.
+ * @return the id of the source being used to play the sound or CD_MUTE if the sound engine is muted or non functioning 
+ * or CD_NO_SOURCE if a problem occurs setting up the source
+ * 
+ */
+- (ALuint)playSound:(int) soundId sourceGroupId:(int)sourceGroupId pitch:(float) pitch pan:(float) pan gain:(float) gain loop:(BOOL) loop {
+
+#ifdef CD_DEBUG
+        //Sanity check parameters - only in DEBUG
+        NSAssert(soundId >= 0, @"soundId can not be negative");
+        NSAssert(soundId < bufferTotal, @"soundId exceeds limit");
+        NSAssert(sourceGroupId >= 0, @"sourceGroupId can not be negative");
+        NSAssert(sourceGroupId < _sourceGroupTotal, @"sourceGroupId exceeds limit");
+        NSAssert(pitch > 0, @"pitch must be greater than zero");
+        NSAssert(pan >= -1 && pan <= 1, @"pan must be between -1 and 1");
+        NSAssert(gain >= 0, @"gain can not be negative");
+#endif
+        //If mute or initialisation has failed or buffer is not loaded then do nothing
+        if (!enabled_ || !functioning_ || _buffers[soundId].bufferState != CD_BS_LOADED || _sourceGroups[sourceGroupId].enabled) {
+#ifdef CD_DEBUG
+                if (!functioning_) {
+                        CDLOGINFO(@"Denshion::CDSoundEngine - sound playback aborted because sound engine is not functioning");
+                } else if (_buffers[soundId].bufferState != CD_BS_LOADED) {
+                        CDLOGINFO(@"Denshion::CDSoundEngine - sound playback aborted because buffer %i is not loaded", soundId);
+                }       
+#endif          
+                return CD_MUTE;
+        }       
+
+        int sourceIndex = [self _getSourceIndexForSourceGroup:sourceGroupId];//This method ensures sourceIndex is valid
+        
+        if (sourceIndex != CD_NO_SOURCE) {
+                ALint state;
+                ALuint source = _sources[sourceIndex].sourceId;
+                ALuint buffer = _buffers[soundId].bufferId;
+                alGetError();//Clear the error code     
+                alGetSourcei(source, AL_SOURCE_STATE, &state);
+                if (state == AL_PLAYING) {
+                        alSourceStop(source);
+                }       
+                alSourcei(source, AL_BUFFER, buffer);//Attach to sound
+                alSourcef(source, AL_PITCH, pitch);//Set pitch
+                alSourcei(source, AL_LOOPING, loop);//Set looping
+                alSourcef(source, AL_GAIN, gain);//Set gain/volume
+                float sourcePosAL[] = {pan, 0.0f, 0.0f};//Set position - just using left and right panning
+                alSourcefv(source, AL_POSITION, sourcePosAL);
+                alGetError();//Clear the error code
+                alSourcePlay(source);
+                if((lastErrorCode_ = alGetError()) == AL_NO_ERROR) {
+                        //Everything was okay
+                        _sources[sourceIndex].attachedBufferId = buffer;
+                        return source;
+                } else {
+                        if (alcGetCurrentContext() == NULL) {
+                                CDLOGINFO(@"Denshion::CDSoundEngine - posting bad OpenAL context message");
+                                [[NSNotificationCenter defaultCenter] postNotificationName:kCDN_BadAlContext object:nil];
+                        }                               
+                        return CD_NO_SOURCE;
+                }       
+        } else {        
+                return CD_NO_SOURCE;
+        }       
+}
+
+-(BOOL) _soundSourceAttachToBuffer:(CDSoundSource*) soundSource soundId:(int) soundId  {
+        //Attach the source to the buffer
+        ALint state;
+        ALuint source = soundSource->_sourceId;
+        ALuint buffer = _buffers[soundId].bufferId;
+        alGetSourcei(source, AL_SOURCE_STATE, &state);
+        if (state == AL_PLAYING) {
+                alSourceStop(source);
+        }
+        alGetError();//Clear the error code     
+        alSourcei(source, AL_BUFFER, buffer);//Attach to sound data
+        if((lastErrorCode_ = alGetError()) == AL_NO_ERROR) {
+                _sources[soundSource->_sourceIndex].attachedBufferId = buffer;
+                //_sourceBufferAttachments[soundSource->_sourceIndex] = buffer;//Keep track of which
+                soundSource->_soundId = soundId;
+                return YES;
+        } else {
+                return NO;
+        }       
+}       
+
+/**
+ * Get a sound source for the specified sound in the specified source group
+ */
+-(CDSoundSource *) soundSourceForSound:(int) soundId sourceGroupId:(int) sourceGroupId 
+{
+        if (!functioning_) {
+                return nil;
+        }       
+        //Check if a source is available
+        int sourceIndex = [self _getSourceIndexForSourceGroup:sourceGroupId];
+        if (sourceIndex != CD_NO_SOURCE) { 
+                CDSoundSource *result = [[CDSoundSource alloc] init:_sources[sourceIndex].sourceId sourceIndex:sourceIndex soundEngine:self];
+                [self _lockSource:sourceIndex lock:YES];
+                //Try to attach to the buffer
+                if ([self _soundSourceAttachToBuffer:result soundId:soundId]) {
+                        //Set to a known state
+                        result.pitch = 1.0f;
+                        result.pan = 0.0f;
+                        result.gain = 1.0f;
+                        result.looping = NO;
+                        return [result autorelease];
+                } else {
+                        //Release the sound source we just created, this will also unlock the source
+                        [result release];
+                        return nil;
+                }       
+        } else {
+                //No available source within that source group
+                return nil;
+        }
+}       
+
+-(void) _soundSourcePreRelease:(CDSoundSource *) soundSource {
+        CDLOGINFO(@"Denshion::CDSoundEngine _soundSourcePreRelease %i",soundSource->_sourceIndex);
+        //Unlock the sound source's source
+        [self _lockSource:soundSource->_sourceIndex lock:NO];
+}       
+
+/**
+ * Stop all sounds playing within a source group
+ */
+- (void) stopSourceGroup:(int) sourceGroupId {
+        
+        if (!functioning_ || sourceGroupId >= _sourceGroupTotal || sourceGroupId < 0) {
+                return;
+        }       
+        int sourceCount = _sourceGroups[sourceGroupId].totalSources;
+        for (int i=0; i < sourceCount; i++) {
+                int sourceIndex = _sourceGroups[sourceGroupId].sourceStatuses[i] >> 1;
+                alSourceStop(_sources[sourceIndex].sourceId);
+        }
+        alGetError();//Clear error in case we stopped any sounds that couldn't be stopped
+}       
+
+/**
+ * Stop a sound playing.
+ * @param sourceId an OpenAL source identifier i.e. the return value of playSound
+ */
+- (void)stopSound:(ALuint) sourceId {
+        if (!functioning_) {
+                return;
+        }       
+        alSourceStop(sourceId);
+        alGetError();//Clear error in case we stopped any sounds that couldn't be stopped
+}
+
+- (void) stopAllSounds {
+        for (int i=0; i < sourceTotal_; i++) {
+                alSourceStop(_sources[i].sourceId);
+        }       
+        alGetError();//Clear error in case we stopped any sounds that couldn't be stopped
+}       
+
+/**
+ * Set a source group as non interruptible.  Default is that source groups are interruptible.
+ * Non interruptible means that if a request to play a sound is made for a source group and there are
+ * no free sources available then the play request will be ignored and CD_NO_SOURCE will be returned.
+ */
+- (void) setSourceGroupNonInterruptible:(int) sourceGroupId isNonInterruptible:(BOOL) isNonInterruptible {
+        //Ensure source group id is valid to prevent memory corruption
+        if (sourceGroupId < 0 || sourceGroupId >= _sourceGroupTotal) {
+                CDLOG(@"Denshion::CDSoundEngine setSourceGroupNonInterruptible invalid source group id %i",sourceGroupId);
+                return;
+        }       
+        
+        if (isNonInterruptible) {
+                _sourceGroups[sourceGroupId].nonInterruptible = true;
+        } else {
+                _sourceGroups[sourceGroupId].nonInterruptible = false;
+        }       
+}
+
+/**
+ * Set the mute property for a source group. If mute is turned on any sounds in that source group
+ * will be stopped and further sounds in that source group will play. However, turning mute off
+ * will not restart any sounds that were playing when mute was turned on. Also the mute setting 
+ * for the sound engine must be taken into account. If the sound engine is mute no sounds will play
+ * no matter what the source group mute setting is.
+ */
+- (void) setSourceGroupEnabled:(int) sourceGroupId enabled:(BOOL) enabled {
+        //Ensure source group id is valid to prevent memory corruption
+        if (sourceGroupId < 0 || sourceGroupId >= _sourceGroupTotal) {
+                CDLOG(@"Denshion::CDSoundEngine setSourceGroupEnabled invalid source group id %i",sourceGroupId);
+                return;
+        }       
+        
+        if (enabled) {
+                _sourceGroups[sourceGroupId].enabled = true;
+                [self stopSourceGroup:sourceGroupId];
+        } else {
+                _sourceGroups[sourceGroupId].enabled = false;   
+        }       
+}
+
+/**
+ * Return the mute property for the source group identified by sourceGroupId
+ */
+- (BOOL) sourceGroupEnabled:(int) sourceGroupId {
+        return _sourceGroups[sourceGroupId].enabled;
+}
+
+-(ALCcontext *) openALContext {
+        return context;
+}       
+
+- (void) _dumpSourceGroupsInfo {
+#ifdef CD_DEBUG 
+        CDLOGINFO(@"-------------- source Group Info --------------");
+        for (int i=0; i < _sourceGroupTotal; i++) {
+                CDLOGINFO(@"Group: %i start:%i total:%i",i,_sourceGroups[i].startIndex, _sourceGroups[i].totalSources);
+                CDLOGINFO(@"----- mute:%i nonInterruptible:%i",_sourceGroups[i].enabled, _sourceGroups[i].nonInterruptible);
+                CDLOGINFO(@"----- Source statuses ----");
+                for (int j=0; j < _sourceGroups[i].totalSources; j++) {
+                        CDLOGINFO(@"Source status:%i index=%i locked=%i",j,_sourceGroups[i].sourceStatuses[j] >> 1, _sourceGroups[i].sourceStatuses[j] & 1);
+                }       
+        }       
+#endif  
+}       
+
+@end
+
+///////////////////////////////////////////////////////////////////////////////////////
+@implementation CDSoundSource
+
+@synthesize lastError;
+
+//Macro for handling the al error code
+#define CDSOUNDSOURCE_UPDATE_LAST_ERROR (lastError = alGetError())
+#define CDSOUNDSOURCE_ERROR_HANDLER ( CDSOUNDSOURCE_UPDATE_LAST_ERROR == AL_NO_ERROR)
+
+-(id)init:(ALuint) theSourceId sourceIndex:(int) index soundEngine:(CDSoundEngine*) engine {
+        if ((self = [super init])) {
+                _sourceId = theSourceId;
+                _engine = engine;
+                _sourceIndex = index;
+                enabled_ = YES;
+                mute_ = NO;
+                _preMuteGain = self.gain;
+        } 
+        return self;
+}
+
+-(void) dealloc
+{
+        CDLOGINFO(@"Denshion::CDSoundSource deallocated %i",self->_sourceIndex);
+
+        //Notify sound engine we are about to release
+        [_engine _soundSourcePreRelease:self];
+        [super dealloc];
+}       
+
+- (void) setPitch:(float) newPitchValue {
+        alSourcef(_sourceId, AL_PITCH, newPitchValue);
+        CDSOUNDSOURCE_UPDATE_LAST_ERROR;
+}       
+
+- (void) setGain:(float) newGainValue {
+        if (!mute_) {
+                alSourcef(_sourceId, AL_GAIN, newGainValue);    
+        } else {
+                _preMuteGain = newGainValue;
+        }       
+        CDSOUNDSOURCE_UPDATE_LAST_ERROR;
+}
+
+- (void) setPan:(float) newPanValue {
+        float sourcePosAL[] = {newPanValue, 0.0f, 0.0f};//Set position - just using left and right panning
+        alSourcefv(_sourceId, AL_POSITION, sourcePosAL);
+        CDSOUNDSOURCE_UPDATE_LAST_ERROR;
+
+}
+
+- (void) setLooping:(BOOL) newLoopingValue {
+        alSourcei(_sourceId, AL_LOOPING, newLoopingValue);
+        CDSOUNDSOURCE_UPDATE_LAST_ERROR;
+
+}
+
+- (BOOL) isPlaying {
+        ALint state;
+        alGetSourcei(_sourceId, AL_SOURCE_STATE, &state);
+        CDSOUNDSOURCE_UPDATE_LAST_ERROR;
+        return (state == AL_PLAYING);
+}       
+
+- (float) pitch {
+        ALfloat pitchVal;
+        alGetSourcef(_sourceId, AL_PITCH, &pitchVal);
+        CDSOUNDSOURCE_UPDATE_LAST_ERROR;
+        return pitchVal;
+}
+
+- (float) pan {
+        ALfloat sourcePosAL[] = {0.0f,0.0f,0.0f};
+        alGetSourcefv(_sourceId, AL_POSITION, sourcePosAL);
+        CDSOUNDSOURCE_UPDATE_LAST_ERROR;
+        return sourcePosAL[0];
+}
+
+- (float) gain {
+        if (!mute_) {
+                ALfloat val;
+                alGetSourcef(_sourceId, AL_GAIN, &val);
+                CDSOUNDSOURCE_UPDATE_LAST_ERROR;
+                return val;
+        } else {
+                return _preMuteGain;
+        }       
+}       
+
+- (BOOL) looping {
+        ALfloat val;
+        alGetSourcef(_sourceId, AL_LOOPING, &val);
+        CDSOUNDSOURCE_UPDATE_LAST_ERROR;
+        return val;
+}
+
+-(BOOL) stop {
+        alSourceStop(_sourceId);
+        return CDSOUNDSOURCE_ERROR_HANDLER;
+}       
+
+-(BOOL) play {
+        if (enabled_) {
+                alSourcePlay(_sourceId);
+                CDSOUNDSOURCE_UPDATE_LAST_ERROR;
+                if (lastError != AL_NO_ERROR) {
+                        if (alcGetCurrentContext() == NULL) {
+                                CDLOGINFO(@"Denshion::CDSoundSource - posting bad OpenAL context message");
+                                [[NSNotificationCenter defaultCenter] postNotificationName:kCDN_BadAlContext object:nil];
+                        }       
+                        return NO;
+                } else {
+                        return YES;
+                }       
+        } else {
+                return NO;
+        }
+}       
+
+-(BOOL) pause {
+        alSourcePause(_sourceId);
+        return CDSOUNDSOURCE_ERROR_HANDLER;
+}
+
+-(BOOL) rewind {
+        alSourceRewind(_sourceId);
+        return CDSOUNDSOURCE_ERROR_HANDLER;
+}
+
+-(void) setSoundId:(int) soundId {
+        [_engine _soundSourceAttachToBuffer:self soundId:soundId];
+}
+
+-(int) soundId {
+        return _soundId;
+}       
+
+-(float) durationInSeconds {
+        return [_engine bufferDurationInSeconds:_soundId];
+}       
+
+#pragma mark CDSoundSource AudioInterrupt protocol
+- (BOOL) mute {
+        return mute_;
+}       
+
+/**
+ * Setting mute silences all sounds but playing sounds continue to advance playback
+ */
+- (void) setMute:(BOOL) newMuteValue {
+        
+        if (newMuteValue == mute_) {
+                return;
+        }
+        
+        if (newMuteValue) {
+                //Remember what the gain was
+                _preMuteGain = self.gain;
+                self.gain = 0.0f;
+                mute_ = newMuteValue;//Make sure this is done after setting the gain property as the setter behaves differently depending on mute value
+        } else {
+                //Restore gain to what it was before being muted
+                mute_ = newMuteValue;
+                self.gain = _preMuteGain;
+        }       
+}
+
+- (BOOL) enabled {
+        return enabled_;
+}
+
+- (void) setEnabled:(BOOL)enabledValue
+{
+        if (enabled_ == enabledValue) {
+                return;
+        }       
+        enabled_ = enabledValue;
+        if (enabled_ == NO) {
+                [self stop];
+        }       
+}       
+
+@end
+
+////////////////////////////////////////////////////////////////////////////
+#pragma mark -
+#pragma mark CDAudioInterruptTargetGroup
+
+@implementation CDAudioInterruptTargetGroup
+
+-(id) init {
+        if ((self = [super init])) {
+                children_ = [[NSMutableArray alloc] initWithCapacity:32];
+                enabled_ = YES;
+                mute_ = NO;
+        }
+        return self;
+}       
+
+-(void) addAudioInterruptTarget:(NSObject<CDAudioInterruptProtocol>*) interruptibleTarget {
+        //Synchronize child with group settings;
+        [interruptibleTarget setMute:mute_];
+        [interruptibleTarget setEnabled:enabled_];
+        [children_ addObject:interruptibleTarget];
+}       
+
+-(void) removeAudioInterruptTarget:(NSObject<CDAudioInterruptProtocol>*) interruptibleTarget {
+        [children_ removeObjectIdenticalTo:interruptibleTarget];
+}       
+
+- (BOOL) mute {
+        return mute_;
+}       
+
+/**
+ * Setting mute silences all sounds but playing sounds continue to advance playback
+ */
+- (void) setMute:(BOOL) newMuteValue {
+        
+        if (newMuteValue == mute_) {
+                return;
+        }
+        
+        for (NSObject<CDAudioInterruptProtocol>* target in children_) {
+                [target setMute:newMuteValue];
+        }       
+}
+
+- (BOOL) enabled {
+        return enabled_;
+}
+
+- (void) setEnabled:(BOOL)enabledValue
+{
+        if (enabledValue == enabled_) {
+                return;
+        }
+        
+        for (NSObject<CDAudioInterruptProtocol>* target in children_) {
+                [target setEnabled:enabledValue];
+        }       
+}       
+
+@end
+
+
+
+////////////////////////////////////////////////////////////////////////////
+
+#pragma mark -
+#pragma mark CDAsynchBufferLoader
+
+@implementation CDAsynchBufferLoader
+
+-(id) init:(NSArray *)loadRequests soundEngine:(CDSoundEngine *) theSoundEngine {
+        if ((self = [super init])) {
+                _loadRequests = loadRequests;
+                [_loadRequests retain];
+                _soundEngine = theSoundEngine;
+                [_soundEngine retain];
+        } 
+        return self;
+}       
+
+-(void) main {
+        CDLOGINFO(@"Denshion::CDAsynchBufferLoader - loading buffers");
+        [super main];
+        _soundEngine.asynchLoadProgress = 0.0f;
+
+        if ([_loadRequests count] > 0) {
+                float increment = 1.0f / [_loadRequests count];
+                //Iterate over load request and load
+                for (CDBufferLoadRequest *loadRequest in _loadRequests) {
+                        [_soundEngine loadBuffer:loadRequest.soundId filePath:loadRequest.filePath];
+                        _soundEngine.asynchLoadProgress += increment;
+                }       
+        }       
+        
+        //Completed
+        _soundEngine.asynchLoadProgress = 1.0f;
+        [[NSNotificationCenter defaultCenter] postNotificationName:kCDN_AsynchLoadComplete object:nil];
+        
+}       
+
+-(void) dealloc {
+        [_loadRequests release];
+        [_soundEngine release];
+        [super dealloc];
+}       
+
+@end
+
+
+///////////////////////////////////////////////////////////////////////////////////////
+#pragma mark -
+#pragma mark CDBufferLoadRequest
+
+@implementation CDBufferLoadRequest
+
+@synthesize filePath, soundId;
+
+-(id) init:(int) theSoundId filePath:(const NSString *) theFilePath {
+        if ((self = [super init])) {
+                soundId = theSoundId;
+                filePath = [theFilePath copy];//TODO: is retain necessary or does copy set retain count
+                [filePath retain];
+        } 
+        return self;
+}
+
+-(void) dealloc {
+        [filePath release];
+        [super dealloc];
+}
+
+@end
+
+///////////////////////////////////////////////////////////////////////////////////////
+#pragma mark -
+#pragma mark CDFloatInterpolator
+
+@implementation CDFloatInterpolator
+@synthesize start,end,interpolationType;
+
+-(float) interpolate:(float) t {
+        
+        if (t < 1.0f) {
+                switch (interpolationType) {
+                        case kIT_Linear:
+                                //Linear interpolation
+                                return ((end - start) * t) + start;
+                                
+                        case kIT_SCurve:
+                                //Cubic s curve t^2 * (3 - 2t)
+                                return ((float)(t * t * (3.0 - (2.0 * t))) * (end - start)) + start;
+                                
+                        case kIT_Exponential:   
+                                //Formulas taken from EaseAction
+                                if (end > start) {
+                                        //Fade in
+                                        float logDelta = (t==0) ? 0 : powf(2, 10 * (t/1 - 1)) - 1 * 0.001f;
+                                        return ((end - start) * logDelta) + start;
+                                } else {
+                                        //Fade Out
+                                        float logDelta = (-powf(2, -10 * t/1) + 1);
+                                        return ((end - start) * logDelta) + start;
+                                }
+                        default:
+                                return 0.0f;
+                }
+        } else {
+                return end;
+        } 
+}
+
+-(id) init:(tCDInterpolationType) type startVal:(float) startVal endVal:(float) endVal {
+        if ((self = [super init])) {
+                start = startVal;
+                end = endVal;
+                interpolationType = type;
+        } 
+        return self;
+}
+
+@end
+
+///////////////////////////////////////////////////////////////////////////////////////
+#pragma mark -
+#pragma mark CDPropertyModifier
+
+@implementation CDPropertyModifier
+
+@synthesize stopTargetWhenComplete;
+
+-(id) init:(id) theTarget interpolationType:(tCDInterpolationType) type startVal:(float) startVal endVal:(float) endVal {
+        if ((self = [super init])) {
+                if (target) {
+                        //Release the previous target if there is one
+                        [target release];
+                }       
+                target = theTarget;
+#if CD_DEBUG
+                //Check target is of the required type
+                if (![theTarget isMemberOfClass:[self _allowableType]] ) {
+                        CDLOG(@"Denshion::CDPropertyModifier target is not of type %@",[self _allowableType]);
+                        NSAssert([theTarget isKindOfClass:[CDSoundEngine class]], @"CDPropertyModifier target not of required type");
+                }
+#endif          
+                [target retain];
+                startValue = startVal;
+                endValue = endVal;
+                if (interpolator) {
+                        //Release previous interpolator if there is one
+                        [interpolator release];
+                }       
+                interpolator = [[CDFloatInterpolator alloc] init:type startVal:startVal endVal:endVal];
+                stopTargetWhenComplete = NO;
+        }
+        return self;
+}       
+
+-(void) dealloc {
+        CDLOGINFO(@"Denshion::CDPropertyModifier deallocated %@",self);
+        [target release];
+        [interpolator release];
+        [super dealloc];
+}       
+
+-(void) modify:(float) t {
+        if (t < 1.0) {
+                [self _setTargetProperty:[interpolator interpolate:t]];
+        } else {
+                //At the end
+                [self _setTargetProperty:endValue];
+                if (stopTargetWhenComplete) {
+                        [self _stopTarget];
+                }       
+        }       
+}       
+
+-(float) startValue {
+        return startValue;
+}
+
+-(void) setStartValue:(float) startVal
+{
+        startValue = startVal;
+        interpolator.start = startVal;
+}       
+
+-(float) endValue {
+        return startValue;
+}
+
+-(void) setEndValue:(float) endVal
+{
+        endValue = endVal;
+        interpolator.end = endVal;
+}       
+
+-(tCDInterpolationType) interpolationType {
+        return interpolator.interpolationType;
+}
+
+-(void) setInterpolationType:(tCDInterpolationType) interpolationType {
+        interpolator.interpolationType = interpolationType;
+}       
+
+-(void) _setTargetProperty:(float) newVal {
+
+}       
+
+-(float) _getTargetProperty {
+        return 0.0f;
+}       
+
+-(void) _stopTarget {
+
+}       
+
+-(Class) _allowableType {
+        return [NSObject class];
+}       
+@end
+
+///////////////////////////////////////////////////////////////////////////////////////
+#pragma mark -
+#pragma mark CDSoundSourceFader
+
+@implementation CDSoundSourceFader
+
+-(void) _setTargetProperty:(float) newVal {
+        ((CDSoundSource*)target).gain = newVal;
+}       
+
+-(float) _getTargetProperty {
+        return ((CDSoundSource*)target).gain;
+}
+
+-(void) _stopTarget {
+        [((CDSoundSource*)target) stop];
+}
+
+-(Class) _allowableType {
+        return [CDSoundSource class];
+}       
+
+@end
+
+///////////////////////////////////////////////////////////////////////////////////////
+#pragma mark -
+#pragma mark CDSoundSourcePanner
+
+@implementation CDSoundSourcePanner
+
+-(void) _setTargetProperty:(float) newVal {
+        ((CDSoundSource*)target).pan = newVal;
+}       
+
+-(float) _getTargetProperty {
+        return ((CDSoundSource*)target).pan;
+}
+
+-(void) _stopTarget {
+        [((CDSoundSource*)target) stop];
+}
+
+-(Class) _allowableType {
+        return [CDSoundSource class];
+}       
+
+@end
+
+///////////////////////////////////////////////////////////////////////////////////////
+#pragma mark -
+#pragma mark CDSoundSourcePitchBender
+
+@implementation CDSoundSourcePitchBender
+
+-(void) _setTargetProperty:(float) newVal {
+        ((CDSoundSource*)target).pitch = newVal;
+}       
+
+-(float) _getTargetProperty {
+        return ((CDSoundSource*)target).pitch;
+}
+
+-(void) _stopTarget {
+        [((CDSoundSource*)target) stop];
+}
+
+-(Class) _allowableType {
+        return [CDSoundSource class];
+}       
+
+@end
+
+///////////////////////////////////////////////////////////////////////////////////////
+#pragma mark -
+#pragma mark CDSoundEngineFader
+
+@implementation CDSoundEngineFader
+
+-(void) _setTargetProperty:(float) newVal {
+        ((CDSoundEngine*)target).masterGain = newVal;
+}       
+
+-(float) _getTargetProperty {
+        return ((CDSoundEngine*)target).masterGain;
+}
+
+-(void) _stopTarget {
+        [((CDSoundEngine*)target) stopAllSounds];
+}
+
+-(Class) _allowableType {
+        return [CDSoundEngine class];
+}       
+
+@end
+
+