Convert the CoreAudio backend to the updated backend API

2 files changed, 283 insertions, 178 deletions

diff --git a/Alc/backends/base.h b/Alc/backends/base.h
index 4f398047..961a4d1a 100644
--- a/Alc/backends/base.h
+++ b/Alc/backends/base.h
@@ -137,6 +137,7 @@ static const struct ALCbackendFactoryVtable T##_ALCbackendFactory_vtable = {  \
 
 ALCbackendFactory *ALCpulseBackendFactory_getFactory(void);
 ALCbackendFactory *ALCalsaBackendFactory_getFactory(void);
+ALCbackendFactory *ALCcoreAudioBackendFactory_getFactory(void);
 ALCbackendFactory *ALCossBackendFactory_getFactory(void);
 ALCbackendFactory *ALCjackBackendFactory_getFactory(void);
 ALCbackendFactory *ALCsolarisBackendFactory_getFactory(void);
diff --git a/Alc/backends/coreaudio.c b/Alc/backends/coreaudio.c
index 5e0b03bd..435c0fae 100644
--- a/Alc/backends/coreaudio.c
+++ b/Alc/backends/coreaudio.c
@@ -33,6 +33,8 @@
 #include <AudioUnit/AudioUnit.h>
 #include <AudioToolbox/AudioToolbox.h>
 
+#include "backends/base.h"
+
 
 typedef struct {
     AudioUnit audioUnit;
@@ -51,17 +53,6 @@ typedef struct {
 static const ALCchar ca_device[] = "CoreAudio Default";
 
 
-static void destroy_buffer_list(AudioBufferList* list)
-{
-    if(list)
-    {
-        UInt32 i;
-        for(i = 0;i < list->mNumberBuffers;i++)
-            free(list->mBuffers[i].mData);
-        free(list);
-    }
-}
-
 static AudioBufferList* allocate_buffer_list(UInt32 channelCount, UInt32 byteSize)
 {
     AudioBufferList *list;
@@ -83,70 +74,85 @@ static AudioBufferList* allocate_buffer_list(UInt32 channelCount, UInt32 byteSiz
     return list;
 }
 
-static OSStatus ca_callback(void *inRefCon, AudioUnitRenderActionFlags *ioActionFlags, const AudioTimeStamp *inTimeStamp,
-                            UInt32 inBusNumber, UInt32 inNumberFrames, AudioBufferList *ioData)
+static void destroy_buffer_list(AudioBufferList* list)
 {
-    ALCdevice *device = (ALCdevice*)inRefCon;
-    ca_data *data = (ca_data*)device->ExtraData;
-
-    ALCdevice_Lock(device);
-    aluMixData(device, ioData->mBuffers[0].mData,
-               ioData->mBuffers[0].mDataByteSize / data->frameSize);
-    ALCdevice_Unlock(device);
-
-    return noErr;
+    if(list)
+    {
+        UInt32 i;
+        for(i = 0;i < list->mNumberBuffers;i++)
+            free(list->mBuffers[i].mData);
+        free(list);
+    }
 }
 
-static OSStatus ca_capture_conversion_callback(AudioConverterRef inAudioConverter, UInt32 *ioNumberDataPackets,
-        AudioBufferList *ioData, AudioStreamPacketDescription **outDataPacketDescription, void* inUserData)
-{
-    ALCdevice *device = (ALCdevice*)inUserData;
-    ca_data *data = (ca_data*)device->ExtraData;
 
-    // Read from the ring buffer and store temporarily in a large buffer
-    ll_ringbuffer_read(data->ring, data->resampleBuffer, *ioNumberDataPackets);
+typedef struct ALCcoreAudioPlayback {
+    DERIVE_FROM_TYPE(ALCbackend);
 
-    // Set the input data
-    ioData->mNumberBuffers = 1;
-    ioData->mBuffers[0].mNumberChannels = data->format.mChannelsPerFrame;
-    ioData->mBuffers[0].mData = data->resampleBuffer;
-    ioData->mBuffers[0].mDataByteSize = (*ioNumberDataPackets) * data->format.mBytesPerFrame;
+    AudioUnit audioUnit;
 
-    return noErr;
+    ALuint frameSize;
+    AudioStreamBasicDescription format;    // This is the OpenAL format as a CoreAudio ASBD
+} ALCcoreAudioPlayback;
+
+static void ALCcoreAudioPlayback_Construct(ALCcoreAudioPlayback *self, ALCdevice *device);
+static void ALCcoreAudioPlayback_Destruct(ALCcoreAudioPlayback *self);
+static ALCenum ALCcoreAudioPlayback_open(ALCcoreAudioPlayback *self, const ALCchar *name);
+static void ALCcoreAudioPlayback_close(ALCcoreAudioPlayback *self);
+static ALCboolean ALCcoreAudioPlayback_reset(ALCcoreAudioPlayback *self);
+static ALCboolean ALCcoreAudioPlayback_start(ALCcoreAudioPlayback *self);
+static void ALCcoreAudioPlayback_stop(ALCcoreAudioPlayback *self);
+static DECLARE_FORWARD2(ALCcoreAudioPlayback, ALCbackend, ALCenum, captureSamples, void*, ALCuint)
+static DECLARE_FORWARD(ALCcoreAudioPlayback, ALCbackend, ALCuint, availableSamples)
+static DECLARE_FORWARD(ALCcoreAudioPlayback, ALCbackend, ClockLatency, getClockLatency)
+static DECLARE_FORWARD(ALCcoreAudioPlayback, ALCbackend, void, lock)
+static DECLARE_FORWARD(ALCcoreAudioPlayback, ALCbackend, void, unlock)
+DECLARE_DEFAULT_ALLOCATORS(ALCcoreAudioPlayback)
+
+DEFINE_ALCBACKEND_VTABLE(ALCcoreAudioPlayback);
+
+
+static void ALCcoreAudioPlayback_Construct(ALCcoreAudioPlayback *self, ALCdevice *device)
+{
+    ALCbackend_Construct(STATIC_CAST(ALCbackend, self), device);
+    SET_VTABLE2(ALCcoreAudioPlayback, ALCbackend, self);
+
+    self->frameSize = 0;
+    memset(&self->format, 0, sizeof(self->format));
 }
 
-static OSStatus ca_capture_callback(void *inRefCon, AudioUnitRenderActionFlags *ioActionFlags,
-                                    const AudioTimeStamp *inTimeStamp, UInt32 inBusNumber,
-                                    UInt32 inNumberFrames, AudioBufferList *ioData)
+static void ALCcoreAudioPlayback_Destruct(ALCcoreAudioPlayback *self)
 {
-    ALCdevice *device = (ALCdevice*)inRefCon;
-    ca_data *data = (ca_data*)device->ExtraData;
-    AudioUnitRenderActionFlags flags = 0;
-    OSStatus err;
+    ALCbackend_Destruct(STATIC_CAST(ALCbackend, self));
+}
 
-    // fill the bufferList with data from the input device
-    err = AudioUnitRender(data->audioUnit, &flags, inTimeStamp, 1, inNumberFrames, data->bufferList);
-    if(err != noErr)
-    {
-        ERR("AudioUnitRender error: %d\n", err);
-        return err;
-    }
 
-    ll_ringbuffer_write(data->ring, data->bufferList->mBuffers[0].mData, inNumberFrames);
+static OSStatus ALCcoreAudioPlayback_MixerProc(void *inRefCon,
+  AudioUnitRenderActionFlags* UNUSED(ioActionFlags), const AudioTimeStamp* UNUSED(inTimeStamp),
+  UInt32 UNUSED(inBusNumber), UInt32 UNUSED(inNumberFrames), AudioBufferList *ioData)
+{
+    ALCcoreAudioPlayback *self = inRefCon;
+    ALCdevice *device = STATIC_CAST(ALCbackend,self)->mDevice;
+
+    ALCdevice_Lock(device);
+    aluMixData(device, ioData->mBuffers[0].mData,
+               ioData->mBuffers[0].mDataByteSize / self->frameSize);
+    ALCdevice_Unlock(device);
 
     return noErr;
 }
 
-static ALCenum ca_open_playback(ALCdevice *device, const ALCchar *deviceName)
+
+static ALCenum ALCcoreAudioPlayback_open(ALCcoreAudioPlayback *self, const ALCchar *name)
 {
+    ALCdevice *device = STATIC_CAST(ALCbackend,self)->mDevice;
     AudioComponentDescription desc;
     AudioComponent comp;
-    ca_data *data;
     OSStatus err;
 
-    if(!deviceName)
-        deviceName = ca_device;
-    else if(strcmp(deviceName, ca_device) != 0)
+    if(!name)
+        name = ca_device;
+    else if(strcmp(name, ca_device) != 0)
         return ALC_INVALID_VALUE;
 
     /* open the default output unit */
@@ -163,57 +169,47 @@ static ALCenum ca_open_playback(ALCdevice *device, const ALCchar *deviceName)
         return ALC_INVALID_VALUE;
     }
 
-    data = calloc(1, sizeof(*data));
-
-    err = AudioComponentInstanceNew(comp, &data->audioUnit);
+    err = AudioComponentInstanceNew(comp, &self->audioUnit);
     if(err != noErr)
     {
         ERR("AudioComponentInstanceNew failed\n");
-        free(data);
         return ALC_INVALID_VALUE;
     }
 
     /* init and start the default audio unit... */
-    err = AudioUnitInitialize(data->audioUnit);
+    err = AudioUnitInitialize(self->audioUnit);
     if(err != noErr)
     {
         ERR("AudioUnitInitialize failed\n");
-        AudioComponentInstanceDispose(data->audioUnit);
-        free(data);
+        AudioComponentInstanceDispose(self->audioUnit);
         return ALC_INVALID_VALUE;
     }
 
-    alstr_copy_cstr(&device->DeviceName, deviceName);
-    device->ExtraData = data;
+    alstr_copy_cstr(&device->DeviceName, name);
     return ALC_NO_ERROR;
 }
 
-static void ca_close_playback(ALCdevice *device)
+static void ALCcoreAudioPlayback_close(ALCcoreAudioPlayback *self)
 {
-    ca_data *data = (ca_data*)device->ExtraData;
-
-    AudioUnitUninitialize(data->audioUnit);
-    AudioComponentInstanceDispose(data->audioUnit);
-
-    free(data);
-    device->ExtraData = NULL;
+    AudioUnitUninitialize(self->audioUnit);
+    AudioComponentInstanceDispose(self->audioUnit);
 }
 
-static ALCboolean ca_reset_playback(ALCdevice *device)
+static ALCboolean ALCcoreAudioPlayback_reset(ALCcoreAudioPlayback *self)
 {
-    ca_data *data = (ca_data*)device->ExtraData;
+    ALCdevice *device = STATIC_CAST(ALCbackend,self)->mDevice;
     AudioStreamBasicDescription streamFormat;
     AURenderCallbackStruct input;
     OSStatus err;
     UInt32 size;
 
-    err = AudioUnitUninitialize(data->audioUnit);
+    err = AudioUnitUninitialize(self->audioUnit);
     if(err != noErr)
         ERR("-- AudioUnitUninitialize failed.\n");
 
     /* retrieve default output unit's properties (output side) */
     size = sizeof(AudioStreamBasicDescription);
-    err = AudioUnitGetProperty(data->audioUnit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Output, 0, &streamFormat, &size);
+    err = AudioUnitGetProperty(self->audioUnit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Output, 0, &streamFormat, &size);
     if(err != noErr || size != sizeof(AudioStreamBasicDescription))
     {
         ERR("AudioUnitGetProperty failed\n");
@@ -231,7 +227,7 @@ static ALCboolean ca_reset_playback(ALCdevice *device)
 #endif
 
     /* set default output unit's input side to match output side */
-    err = AudioUnitSetProperty(data->audioUnit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Input, 0, &streamFormat, size);
+    err = AudioUnitSetProperty(self->audioUnit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Input, 0, &streamFormat, size);
     if(err != noErr)
     {
         ERR("AudioUnitSetProperty failed\n");
@@ -315,7 +311,7 @@ static ALCboolean ca_reset_playback(ALCdevice *device)
     streamFormat.mFormatFlags |= kAudioFormatFlagsNativeEndian |
                                  kLinearPCMFormatFlagIsPacked;
 
-    err = AudioUnitSetProperty(data->audioUnit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Input, 0, &streamFormat, sizeof(AudioStreamBasicDescription));
+    err = AudioUnitSetProperty(self->audioUnit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Input, 0, &streamFormat, sizeof(AudioStreamBasicDescription));
     if(err != noErr)
     {
         ERR("AudioUnitSetProperty failed\n");
@@ -323,11 +319,11 @@ static ALCboolean ca_reset_playback(ALCdevice *device)
     }
 
     /* setup callback */
-    data->frameSize = FrameSizeFromDevFmt(device->FmtChans, device->FmtType);
-    input.inputProc = ca_callback;
-    input.inputProcRefCon = device;
+    self->frameSize = FrameSizeFromDevFmt(device->FmtChans, device->FmtType);
+    input.inputProc = ALCcoreAudioPlayback_MixerProc;
+    input.inputProcRefCon = self;
 
-    err = AudioUnitSetProperty(data->audioUnit, kAudioUnitProperty_SetRenderCallback, kAudioUnitScope_Input, 0, &input, sizeof(AURenderCallbackStruct));
+    err = AudioUnitSetProperty(self->audioUnit, kAudioUnitProperty_SetRenderCallback, kAudioUnitScope_Input, 0, &input, sizeof(AURenderCallbackStruct));
     if(err != noErr)
     {
         ERR("AudioUnitSetProperty failed\n");
@@ -335,7 +331,7 @@ static ALCboolean ca_reset_playback(ALCdevice *device)
     }
 
     /* init the default audio unit... */
-    err = AudioUnitInitialize(data->audioUnit);
+    err = AudioUnitInitialize(self->audioUnit);
     if(err != noErr)
     {
         ERR("AudioUnitInitialize failed\n");
@@ -345,12 +341,9 @@ static ALCboolean ca_reset_playback(ALCdevice *device)
     return ALC_TRUE;
 }
 
-static ALCboolean ca_start_playback(ALCdevice *device)
+static ALCboolean ALCcoreAudioPlayback_start(ALCcoreAudioPlayback *self)
 {
-    ca_data *data = (ca_data*)device->ExtraData;
-    OSStatus err;
-
-    err = AudioOutputUnitStart(data->audioUnit);
+    OSStatus err = AudioOutputUnitStart(self->audioUnit);
     if(err != noErr)
     {
         ERR("AudioOutputUnitStart failed\n");
@@ -360,18 +353,107 @@ static ALCboolean ca_start_playback(ALCdevice *device)
     return ALC_TRUE;
 }
 
-static void ca_stop_playback(ALCdevice *device)
+static void ALCcoreAudioPlayback_stop(ALCcoreAudioPlayback *self)
 {
-    ca_data *data = (ca_data*)device->ExtraData;
+    OSStatus err = AudioOutputUnitStop(self->audioUnit);
+    if(err != noErr)
+        ERR("AudioOutputUnitStop failed\n");
+}
+
+
+
+
+typedef struct ALCcoreAudioCapture {
+    DERIVE_FROM_TYPE(ALCbackend);
+
+    AudioUnit audioUnit;
+
+    ALuint frameSize;
+    ALdouble sampleRateRatio;              // Ratio of hardware sample rate / requested sample rate
+    AudioStreamBasicDescription format;    // This is the OpenAL format as a CoreAudio ASBD
+
+    AudioConverterRef audioConverter;      // Sample rate converter if needed
+    AudioBufferList *bufferList;           // Buffer for data coming from the input device
+    ALCvoid *resampleBuffer;               // Buffer for returned RingBuffer data when resampling
+
+    ll_ringbuffer_t *ring;
+} ALCcoreAudioCapture;
+
+static void ALCcoreAudioCapture_Construct(ALCcoreAudioCapture *self, ALCdevice *device);
+static void ALCcoreAudioCapture_Destruct(ALCcoreAudioCapture *self);
+static ALCenum ALCcoreAudioCapture_open(ALCcoreAudioCapture *self, const ALCchar *name);
+static void ALCcoreAudioCapture_close(ALCcoreAudioCapture *self);
+static DECLARE_FORWARD(ALCcoreAudioCapture, ALCbackend, ALCboolean, reset)
+static ALCboolean ALCcoreAudioCapture_start(ALCcoreAudioCapture *self);
+static void ALCcoreAudioCapture_stop(ALCcoreAudioCapture *self);
+static ALCenum ALCcoreAudioCapture_captureSamples(ALCcoreAudioCapture *self, ALCvoid *buffer, ALCuint samples);
+static ALCuint ALCcoreAudioCapture_availableSamples(ALCcoreAudioCapture *self);
+static DECLARE_FORWARD(ALCcoreAudioCapture, ALCbackend, ClockLatency, getClockLatency)
+static DECLARE_FORWARD(ALCcoreAudioCapture, ALCbackend, void, lock)
+static DECLARE_FORWARD(ALCcoreAudioCapture, ALCbackend, void, unlock)
+DECLARE_DEFAULT_ALLOCATORS(ALCcoreAudioCapture)
+
+DEFINE_ALCBACKEND_VTABLE(ALCcoreAudioCapture);
+
+
+static void ALCcoreAudioCapture_Construct(ALCcoreAudioCapture *self, ALCdevice *device)
+{
+    ALCbackend_Construct(STATIC_CAST(ALCbackend, self), device);
+    SET_VTABLE2(ALCcoreAudioCapture, ALCbackend, self);
+
+}
+
+static void ALCcoreAudioCapture_Destruct(ALCcoreAudioCapture *self)
+{
+    ALCbackend_Destruct(STATIC_CAST(ALCbackend, self));
+}
+
+
+static OSStatus ALCcoreAudioCapture_RecordProc(void *inRefCon,
+  AudioUnitRenderActionFlags* UNUSED(ioActionFlags),
+  const AudioTimeStamp *inTimeStamp, UInt32 UNUSED(inBusNumber),
+  UInt32 inNumberFrames, AudioBufferList* UNUSED(ioData))
+{
+    ALCcoreAudioCapture *self = inRefCon;
+    AudioUnitRenderActionFlags flags = 0;
     OSStatus err;
 
-    err = AudioOutputUnitStop(data->audioUnit);
+    // fill the bufferList with data from the input device
+    err = AudioUnitRender(self->audioUnit, &flags, inTimeStamp, 1, inNumberFrames, self->bufferList);
     if(err != noErr)
-        ERR("AudioOutputUnitStop failed\n");
+    {
+        ERR("AudioUnitRender error: %d\n", err);
+        return err;
+    }
+
+    ll_ringbuffer_write(self->ring, self->bufferList->mBuffers[0].mData, inNumberFrames);
+
+    return noErr;
+}
+
+static OSStatus ALCcoreAudioCapture_ConvertCallback(AudioConverterRef UNUSED(inAudioConverter),
+  UInt32 *ioNumberDataPackets, AudioBufferList *ioData,
+  AudioStreamPacketDescription** UNUSED(outDataPacketDescription),
+  void *inUserData)
+{
+    ALCcoreAudioCapture *self = inUserData;
+
+    // Read from the ring buffer and store temporarily in a large buffer
+    ll_ringbuffer_read(self->ring, self->resampleBuffer, *ioNumberDataPackets);
+
+    // Set the input data
+    ioData->mNumberBuffers = 1;
+    ioData->mBuffers[0].mNumberChannels = self->format.mChannelsPerFrame;
+    ioData->mBuffers[0].mData = self->resampleBuffer;
+    ioData->mBuffers[0].mDataByteSize = (*ioNumberDataPackets) * self->format.mBytesPerFrame;
+
+    return noErr;
 }
 
-static ALCenum ca_open_capture(ALCdevice *device, const ALCchar *deviceName)
+
+static ALCenum ALCcoreAudioCapture_open(ALCcoreAudioCapture *self, const ALCchar *name)
 {
+    ALCdevice *device = STATIC_CAST(ALCbackend,self)->mDevice;
     AudioStreamBasicDescription requestedFormat;  // The application requested format
     AudioStreamBasicDescription hardwareFormat;   // The hardware format
     AudioStreamBasicDescription outputFormat;     // The AudioUnit output format
@@ -383,12 +465,11 @@ static ALCenum ca_open_capture(ALCdevice *device, const ALCchar *deviceName)
     AudioObjectPropertyAddress propertyAddress;
     UInt32 enableIO;
     AudioComponent comp;
-    ca_data *data;
     OSStatus err;
 
-    if(!deviceName)
-        deviceName = ca_device;
-    else if(strcmp(deviceName, ca_device) != 0)
+    if(!name)
+        name = ca_device;
+    else if(strcmp(name, ca_device) != 0)
         return ALC_INVALID_VALUE;
 
     desc.componentType = kAudioUnitType_Output;
@@ -405,11 +486,8 @@ static ALCenum ca_open_capture(ALCdevice *device, const ALCchar *deviceName)
         return ALC_INVALID_VALUE;
     }
 
-    data = calloc(1, sizeof(*data));
-    device->ExtraData = data;
-
     // Open the component
-    err = AudioComponentInstanceNew(comp, &data->audioUnit);
+    err = AudioComponentInstanceNew(comp, &self->audioUnit);
     if(err != noErr)
     {
         ERR("AudioComponentInstanceNew failed\n");
@@ -418,7 +496,7 @@ static ALCenum ca_open_capture(ALCdevice *device, const ALCchar *deviceName)
 
     // Turn off AudioUnit output
     enableIO = 0;
-    err = AudioUnitSetProperty(data->audioUnit, kAudioOutputUnitProperty_EnableIO, kAudioUnitScope_Output, 0, &enableIO, sizeof(ALuint));
+    err = AudioUnitSetProperty(self->audioUnit, kAudioOutputUnitProperty_EnableIO, kAudioUnitScope_Output, 0, &enableIO, sizeof(ALuint));
     if(err != noErr)
     {
         ERR("AudioUnitSetProperty failed\n");
@@ -427,7 +505,7 @@ static ALCenum ca_open_capture(ALCdevice *device, const ALCchar *deviceName)
 
     // Turn on AudioUnit input
     enableIO = 1;
-    err = AudioUnitSetProperty(data->audioUnit, kAudioOutputUnitProperty_EnableIO, kAudioUnitScope_Input, 1, &enableIO, sizeof(ALuint));
+    err = AudioUnitSetProperty(self->audioUnit, kAudioOutputUnitProperty_EnableIO, kAudioUnitScope_Input, 1, &enableIO, sizeof(ALuint));
     if(err != noErr)
     {
         ERR("AudioUnitSetProperty failed\n");
@@ -455,7 +533,7 @@ static ALCenum ca_open_capture(ALCdevice *device, const ALCchar *deviceName)
     }
 
     // Track the input device
-    err = AudioUnitSetProperty(data->audioUnit, kAudioOutputUnitProperty_CurrentDevice, kAudioUnitScope_Global, 0, &inputDevice, sizeof(AudioDeviceID));
+    err = AudioUnitSetProperty(self->audioUnit, kAudioOutputUnitProperty_CurrentDevice, kAudioUnitScope_Global, 0, &inputDevice, sizeof(AudioDeviceID));
     if(err != noErr)
     {
         ERR("AudioUnitSetProperty failed\n");
@@ -463,10 +541,10 @@ static ALCenum ca_open_capture(ALCdevice *device, const ALCchar *deviceName)
     }
 
     // set capture callback
-    input.inputProc = ca_capture_callback;
-    input.inputProcRefCon = device;
+    input.inputProc = ALCcoreAudioCapture_RecordProc;
+    input.inputProcRefCon = self;
 
-    err = AudioUnitSetProperty(data->audioUnit, kAudioOutputUnitProperty_SetInputCallback, kAudioUnitScope_Global, 0, &input, sizeof(AURenderCallbackStruct));
+    err = AudioUnitSetProperty(self->audioUnit, kAudioOutputUnitProperty_SetInputCallback, kAudioUnitScope_Global, 0, &input, sizeof(AURenderCallbackStruct));
     if(err != noErr)
     {
         ERR("AudioUnitSetProperty failed\n");
@@ -474,7 +552,7 @@ static ALCenum ca_open_capture(ALCdevice *device, const ALCchar *deviceName)
     }
 
     // Initialize the device
-    err = AudioUnitInitialize(data->audioUnit);
+    err = AudioUnitInitialize(self->audioUnit);
     if(err != noErr)
     {
         ERR("AudioUnitInitialize failed\n");
@@ -483,7 +561,7 @@ static ALCenum ca_open_capture(ALCdevice *device, const ALCchar *deviceName)
 
     // Get the hardware format
     propertySize = sizeof(AudioStreamBasicDescription);
-    err = AudioUnitGetProperty(data->audioUnit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Input, 1, &hardwareFormat, &propertySize);
+    err = AudioUnitGetProperty(self->audioUnit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Input, 1, &hardwareFormat, &propertySize);
     if(err != noErr || propertySize != sizeof(AudioStreamBasicDescription))
     {
         ERR("AudioUnitGetProperty failed\n");
@@ -545,8 +623,8 @@ static ALCenum ca_open_capture(ALCdevice *device, const ALCchar *deviceName)
     requestedFormat.mFramesPerPacket = 1;
 
     // save requested format description for later use
-    data->format = requestedFormat;
-    data->frameSize = FrameSizeFromDevFmt(device->FmtChans, device->FmtType);
+    self->format = requestedFormat;
+    self->frameSize = FrameSizeFromDevFmt(device->FmtChans, device->FmtType);
 
     // Use intermediate format for sample rate conversion (outputFormat)
     // Set sample rate to the same as hardware for resampling later
@@ -554,11 +632,11 @@ static ALCenum ca_open_capture(ALCdevice *device, const ALCchar *deviceName)
     outputFormat.mSampleRate = hardwareFormat.mSampleRate;
 
     // Determine sample rate ratio for resampling
-    data->sampleRateRatio = outputFormat.mSampleRate / device->Frequency;
+    self->sampleRateRatio = outputFormat.mSampleRate / device->Frequency;
 
     // The output format should be the requested format, but using the hardware sample rate
     // This is because the AudioUnit will automatically scale other properties, except for sample rate
-    err = AudioUnitSetProperty(data->audioUnit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Output, 1, (void *)&outputFormat, sizeof(outputFormat));
+    err = AudioUnitSetProperty(self->audioUnit, kAudioUnitProperty_StreamFormat, kAudioUnitScope_Output, 1, (void *)&outputFormat, sizeof(outputFormat));
     if(err != noErr)
     {
         ERR("AudioUnitSetProperty failed\n");
@@ -566,8 +644,8 @@ static ALCenum ca_open_capture(ALCdevice *device, const ALCchar *deviceName)
     }
 
     // Set the AudioUnit output format frame count
-    outputFrameCount = device->UpdateSize * data->sampleRateRatio;
-    err = AudioUnitSetProperty(data->audioUnit, kAudioUnitProperty_MaximumFramesPerSlice, kAudioUnitScope_Output, 0, &outputFrameCount, sizeof(outputFrameCount));
+    outputFrameCount = device->UpdateSize * self->sampleRateRatio;
+    err = AudioUnitSetProperty(self->audioUnit, kAudioUnitProperty_MaximumFramesPerSlice, kAudioUnitScope_Output, 0, &outputFrameCount, sizeof(outputFrameCount));
     if(err != noErr)
     {
         ERR("AudioUnitSetProperty failed: %d\n", err);
@@ -575,7 +653,7 @@ static ALCenum ca_open_capture(ALCdevice *device, const ALCchar *deviceName)
     }
 
     // Set up sample converter
-    err = AudioConverterNew(&outputFormat, &requestedFormat, &data->audioConverter);
+    err = AudioConverterNew(&outputFormat, &requestedFormat, &self->audioConverter);
     if(err != noErr)
     {
         ERR("AudioConverterNew failed: %d\n", err);
@@ -583,75 +661,71 @@ static ALCenum ca_open_capture(ALCdevice *device, const ALCchar *deviceName)
     }
 
     // Create a buffer for use in the resample callback
-    data->resampleBuffer = malloc(device->UpdateSize * data->frameSize * data->sampleRateRatio);
+    self->resampleBuffer = malloc(device->UpdateSize * self->frameSize * self->sampleRateRatio);
 
     // Allocate buffer for the AudioUnit output
-    data->bufferList = allocate_buffer_list(outputFormat.mChannelsPerFrame, device->UpdateSize * data->frameSize * data->sampleRateRatio);
-    if(data->bufferList == NULL)
+    self->bufferList = allocate_buffer_list(outputFormat.mChannelsPerFrame, device->UpdateSize * self->frameSize * self->sampleRateRatio);
+    if(self->bufferList == NULL)
         goto error;
 
-    data->ring = ll_ringbuffer_create(
-        device->UpdateSize*data->sampleRateRatio*device->NumUpdates + 1,
-        data->frameSize
+    self->ring = ll_ringbuffer_create(
+        device->UpdateSize*self->sampleRateRatio*device->NumUpdates + 1,
+        self->frameSize
     );
-    if(!data->ring) goto error;
+    if(!self->ring) goto error;
 
-    alstr_copy_cstr(&device->DeviceName, deviceName);
+    alstr_copy_cstr(&device->DeviceName, name);
 
     return ALC_NO_ERROR;
 
 error:
-    ll_ringbuffer_free(data->ring);
-    data->ring = NULL;
-    free(data->resampleBuffer);
-    destroy_buffer_list(data->bufferList);
-
-    if(data->audioConverter)
-        AudioConverterDispose(data->audioConverter);
-    if(data->audioUnit)
-        AudioComponentInstanceDispose(data->audioUnit);
+    ll_ringbuffer_free(self->ring);
+    self->ring = NULL;
+    free(self->resampleBuffer);
+    destroy_buffer_list(self->bufferList);
 
-    free(data);
-    device->ExtraData = NULL;
+    if(self->audioConverter)
+        AudioConverterDispose(self->audioConverter);
+    if(self->audioUnit)
+        AudioComponentInstanceDispose(self->audioUnit);
 
     return ALC_INVALID_VALUE;
 }
 
-static void ca_close_capture(ALCdevice *device)
+
+static void ALCcoreAudioCapture_close(ALCcoreAudioCapture *self)
 {
-    ca_data *data = (ca_data*)device->ExtraData;
+    ll_ringbuffer_free(self->ring);
+    self->ring = NULL;
 
-    ll_ringbuffer_free(data->ring);
-    data->ring = NULL;
-    free(data->resampleBuffer);
-    destroy_buffer_list(data->bufferList);
+    free(self->resampleBuffer);
 
-    AudioConverterDispose(data->audioConverter);
-    AudioComponentInstanceDispose(data->audioUnit);
+    destroy_buffer_list(self->bufferList);
 
-    free(data);
-    device->ExtraData = NULL;
+    AudioConverterDispose(self->audioConverter);
+    AudioComponentInstanceDispose(self->audioUnit);
 }
 
-static void ca_start_capture(ALCdevice *device)
+static ALCboolean ALCcoreAudioCapture_start(ALCcoreAudioCapture *self)
 {
-    ca_data *data = (ca_data*)device->ExtraData;
-    OSStatus err = AudioOutputUnitStart(data->audioUnit);
+    OSStatus err = AudioOutputUnitStart(self->audioUnit);
     if(err != noErr)
+    {
         ERR("AudioOutputUnitStart failed\n");
+        return ALC_FALSE;
+    }
+    return ALC_TRUE;
 }
 
-static void ca_stop_capture(ALCdevice *device)
+static void ALCcoreAudioCapture_stop(ALCcoreAudioCapture *self)
 {
-    ca_data *data = (ca_data*)device->ExtraData;
-    OSStatus err = AudioOutputUnitStop(data->audioUnit);
+    OSStatus err = AudioOutputUnitStop(self->audioUnit);
     if(err != noErr)
         ERR("AudioOutputUnitStop failed\n");
 }
 
-static ALCenum ca_capture_samples(ALCdevice *device, ALCvoid *buffer, ALCuint samples)
+static ALCenum ALCcoreAudioCapture_captureSamples(ALCcoreAudioCapture *self, ALCvoid *buffer, ALCuint samples)
 {
-    ca_data *data = (ca_data*)device->ExtraData;
     AudioBufferList *list;
     UInt32 frameCount;
     OSStatus err;
@@ -665,14 +739,15 @@ static ALCenum ca_capture_samples(ALCdevice *device, ALCvoid *buffer, ALCuint sa
 
     // Point the resampling buffer to the capture buffer
     list->mNumberBuffers = 1;
-    list->mBuffers[0].mNumberChannels = data->format.mChannelsPerFrame;
-    list->mBuffers[0].mDataByteSize = samples * data->frameSize;
+    list->mBuffers[0].mNumberChannels = self->format.mChannelsPerFrame;
+    list->mBuffers[0].mDataByteSize = samples * self->frameSize;
     list->mBuffers[0].mData = buffer;
 
     // Resample into another AudioBufferList
     frameCount = samples;
-    err = AudioConverterFillComplexBuffer(data->audioConverter, ca_capture_conversion_callback,
-                                          device, &frameCount, list, NULL);
+    err = AudioConverterFillComplexBuffer(self->audioConverter,
+        ALCcoreAudioCapture_ConvertCallback, self, &frameCount, list, NULL
+    );
     if(err != noErr)
     {
         ERR("AudioConverterFillComplexBuffer error: %d\n", err);
@@ -681,38 +756,47 @@ static ALCenum ca_capture_samples(ALCdevice *device, ALCvoid *buffer, ALCuint sa
     return ALC_NO_ERROR;
 }
 
-static ALCuint ca_available_samples(ALCdevice *device)
+static ALCuint ALCcoreAudioCapture_availableSamples(ALCcoreAudioCapture *self)
 {
-    ca_data *data = device->ExtraData;
-    return ll_ringbuffer_read_space(data->ring) / data->sampleRateRatio;
+    return ll_ringbuffer_read_space(self->ring) / self->sampleRateRatio;
 }
 
 
-static const BackendFuncs ca_funcs = {
-    ca_open_playback,
-    ca_close_playback,
-    ca_reset_playback,
-    ca_start_playback,
-    ca_stop_playback,
-    ca_open_capture,
-    ca_close_capture,
-    ca_start_capture,
-    ca_stop_capture,
-    ca_capture_samples,
-    ca_available_samples
-};
-
-ALCboolean alc_ca_init(BackendFuncs *func_list)
+typedef struct ALCcoreAudioBackendFactory {
+    DERIVE_FROM_TYPE(ALCbackendFactory);
+} ALCcoreAudioBackendFactory;
+#define ALCCOREAUDIOBACKENDFACTORY_INITIALIZER { { GET_VTABLE2(ALCcoreAudioBackendFactory, ALCbackendFactory) } }
+
+ALCbackendFactory *ALCcoreAudioBackendFactory_getFactory(void);
+
+static ALCboolean ALCcoreAudioBackendFactory_init(ALCcoreAudioBackendFactory *self);
+static DECLARE_FORWARD(ALCcoreAudioBackendFactory, ALCbackendFactory, void, deinit)
+static ALCboolean ALCcoreAudioBackendFactory_querySupport(ALCcoreAudioBackendFactory *self, ALCbackend_Type type);
+static void ALCcoreAudioBackendFactory_probe(ALCcoreAudioBackendFactory *self, enum DevProbe type);
+static ALCbackend* ALCcoreAudioBackendFactory_createBackend(ALCcoreAudioBackendFactory *self, ALCdevice *device, ALCbackend_Type type);
+DEFINE_ALCBACKENDFACTORY_VTABLE(ALCcoreAudioBackendFactory);
+
+
+ALCbackendFactory *ALCcoreAudioBackendFactory_getFactory(void)
+{
+    static ALCcoreAudioBackendFactory factory = ALCCOREAUDIOBACKENDFACTORY_INITIALIZER;
+    return STATIC_CAST(ALCbackendFactory, &factory);
+}
+
+
+static ALCboolean ALCcoreAudioBackendFactory_init(ALCcoreAudioBackendFactory* UNUSED(self))
 {
-    *func_list = ca_funcs;
     return ALC_TRUE;
 }
 
-void alc_ca_deinit(void)
+static ALCboolean ALCcoreAudioBackendFactory_querySupport(ALCcoreAudioBackendFactory* UNUSED(self), ALCbackend_Type type)
 {
+    if(type == ALCbackend_Playback || ALCbackend_Capture)
+        return ALC_TRUE;
+    return ALC_FALSE;
 }
 
-void alc_ca_probe(enum DevProbe type)
+static void ALCcoreAudioBackendFactory_probe(ALCcoreAudioBackendFactory* UNUSED(self), enum DevProbe type)
 {
     switch(type)
     {
@@ -724,3 +808,23 @@ void alc_ca_probe(enum DevProbe type)
             break;
     }
 }
+
+static ALCbackend* ALCcoreAudioBackendFactory_createBackend(ALCcoreAudioBackendFactory* UNUSED(self), ALCdevice *device, ALCbackend_Type type)
+{
+    if(type == ALCbackend_Playback)
+    {
+        ALCcoreAudioPlayback *backend;
+        NEW_OBJ(backend, ALCcoreAudioPlayback)(device);
+        if(!backend) return NULL;
+        return STATIC_CAST(ALCbackend, backend);
+    }
+    if(type == ALCbackend_Capture)
+    {
+        ALCcoreAudioCapture *backend;
+        NEW_OBJ(backend, ALCcoreAudioCapture)(device);
+        if(!backend) return NULL;
+        return STATIC_CAST(ALCbackend, backend);
+    }
+
+    return NULL;
+}