*initHEADmaster

1 files changed, 861 insertions, 0 deletions

diff --git a/source/3rd-party/SDL2/src/audio/coreaudio/SDL_coreaudio.m b/source/3rd-party/SDL2/src/audio/coreaudio/SDL_coreaudio.m
new file mode 100644
index 0000000..59242f9
--- /dev/null
+++ b/source/3rd-party/SDL2/src/audio/coreaudio/SDL_coreaudio.m
@@ -0,0 +1,861 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2018 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+#include "../../SDL_internal.h"
+
+#if SDL_AUDIO_DRIVER_COREAUDIO
+
+/* !!! FIXME: clean out some of the macro salsa in here. */
+
+#include "SDL_audio.h"
+#include "SDL_hints.h"
+#include "SDL_timer.h"
+#include "../SDL_audio_c.h"
+#include "../SDL_sysaudio.h"
+#include "SDL_coreaudio.h"
+#include "SDL_assert.h"
+#include "../../thread/SDL_systhread.h"
+
+#define DEBUG_COREAUDIO 0
+
+#define CHECK_RESULT(msg) \
+    if (result != noErr) { \
+        SDL_SetError("CoreAudio error (%s): %d", msg, (int) result); \
+        return 0; \
+    }
+
+#if MACOSX_COREAUDIO
+static const AudioObjectPropertyAddress devlist_address = {
+    kAudioHardwarePropertyDevices,
+    kAudioObjectPropertyScopeGlobal,
+    kAudioObjectPropertyElementMaster
+};
+
+typedef void (*addDevFn)(const char *name, const int iscapture, AudioDeviceID devId, void *data);
+
+typedef struct AudioDeviceList
+{
+    AudioDeviceID devid;
+    SDL_bool alive;
+    struct AudioDeviceList *next;
+} AudioDeviceList;
+
+static AudioDeviceList *output_devs = NULL;
+static AudioDeviceList *capture_devs = NULL;
+
+static SDL_bool
+add_to_internal_dev_list(const int iscapture, AudioDeviceID devId)
+{
+    AudioDeviceList *item = (AudioDeviceList *) SDL_malloc(sizeof (AudioDeviceList));
+    if (item == NULL) {
+        return SDL_FALSE;
+    }
+    item->devid = devId;
+    item->alive = SDL_TRUE;
+    item->next = iscapture ? capture_devs : output_devs;
+    if (iscapture) {
+        capture_devs = item;
+    } else {
+        output_devs = item;
+    }
+
+    return SDL_TRUE;
+}
+
+static void
+addToDevList(const char *name, const int iscapture, AudioDeviceID devId, void *data)
+{
+    if (add_to_internal_dev_list(iscapture, devId)) {
+        SDL_AddAudioDevice(iscapture, name, (void *) ((size_t) devId));
+    }
+}
+
+static void
+build_device_list(int iscapture, addDevFn addfn, void *addfndata)
+{
+    OSStatus result = noErr;
+    UInt32 size = 0;
+    AudioDeviceID *devs = NULL;
+    UInt32 i = 0;
+    UInt32 max = 0;
+
+    result = AudioObjectGetPropertyDataSize(kAudioObjectSystemObject,
+                                            &devlist_address, 0, NULL, &size);
+    if (result != kAudioHardwareNoError)
+        return;
+
+    devs = (AudioDeviceID *) alloca(size);
+    if (devs == NULL)
+        return;
+
+    result = AudioObjectGetPropertyData(kAudioObjectSystemObject,
+                                        &devlist_address, 0, NULL, &size, devs);
+    if (result != kAudioHardwareNoError)
+        return;
+
+    max = size / sizeof (AudioDeviceID);
+    for (i = 0; i < max; i++) {
+        CFStringRef cfstr = NULL;
+        char *ptr = NULL;
+        AudioDeviceID dev = devs[i];
+        AudioBufferList *buflist = NULL;
+        int usable = 0;
+        CFIndex len = 0;
+        const AudioObjectPropertyAddress addr = {
+            kAudioDevicePropertyStreamConfiguration,
+            iscapture ? kAudioDevicePropertyScopeInput : kAudioDevicePropertyScopeOutput,
+            kAudioObjectPropertyElementMaster
+        };
+
+        const AudioObjectPropertyAddress nameaddr = {
+            kAudioObjectPropertyName,
+            iscapture ? kAudioDevicePropertyScopeInput : kAudioDevicePropertyScopeOutput,
+            kAudioObjectPropertyElementMaster
+        };
+
+        result = AudioObjectGetPropertyDataSize(dev, &addr, 0, NULL, &size);
+        if (result != noErr)
+            continue;
+
+        buflist = (AudioBufferList *) SDL_malloc(size);
+        if (buflist == NULL)
+            continue;
+
+        result = AudioObjectGetPropertyData(dev, &addr, 0, NULL,
+                                            &size, buflist);
+
+        if (result == noErr) {
+            UInt32 j;
+            for (j = 0; j < buflist->mNumberBuffers; j++) {
+                if (buflist->mBuffers[j].mNumberChannels > 0) {
+                    usable = 1;
+                    break;
+                }
+            }
+        }
+
+        SDL_free(buflist);
+
+        if (!usable)
+            continue;
+
+
+        size = sizeof (CFStringRef);
+        result = AudioObjectGetPropertyData(dev, &nameaddr, 0, NULL, &size, &cfstr);
+        if (result != kAudioHardwareNoError)
+            continue;
+
+        len = CFStringGetMaximumSizeForEncoding(CFStringGetLength(cfstr),
+                                                kCFStringEncodingUTF8);
+
+        ptr = (char *) SDL_malloc(len + 1);
+        usable = ((ptr != NULL) &&
+                  (CFStringGetCString
+                   (cfstr, ptr, len + 1, kCFStringEncodingUTF8)));
+
+        CFRelease(cfstr);
+
+        if (usable) {
+            len = strlen(ptr);
+            /* Some devices have whitespace at the end...trim it. */
+            while ((len > 0) && (ptr[len - 1] == ' ')) {
+                len--;
+            }
+            usable = (len > 0);
+        }
+
+        if (usable) {
+            ptr[len] = '\0';
+
+#if DEBUG_COREAUDIO
+            printf("COREAUDIO: Found %s device #%d: '%s' (devid %d)\n",
+                   ((iscapture) ? "capture" : "output"),
+                   (int) i, ptr, (int) dev);
+#endif
+            addfn(ptr, iscapture, dev, addfndata);
+        }
+        SDL_free(ptr);  /* addfn() would have copied the string. */
+    }
+}
+
+static void
+free_audio_device_list(AudioDeviceList **list)
+{
+    AudioDeviceList *item = *list;
+    while (item) {
+        AudioDeviceList *next = item->next;
+        SDL_free(item);
+        item = next;
+    }
+    *list = NULL;
+}
+
+static void
+COREAUDIO_DetectDevices(void)
+{
+    build_device_list(SDL_TRUE, addToDevList, NULL);
+    build_device_list(SDL_FALSE, addToDevList, NULL);
+}
+
+static void
+build_device_change_list(const char *name, const int iscapture, AudioDeviceID devId, void *data)
+{
+    AudioDeviceList **list = (AudioDeviceList **) data;
+    AudioDeviceList *item;
+    for (item = *list; item != NULL; item = item->next) {
+        if (item->devid == devId) {
+            item->alive = SDL_TRUE;
+            return;
+        }
+    }
+
+    add_to_internal_dev_list(iscapture, devId);  /* new device, add it. */
+    SDL_AddAudioDevice(iscapture, name, (void *) ((size_t) devId));
+}
+
+static void
+reprocess_device_list(const int iscapture, AudioDeviceList **list)
+{
+    AudioDeviceList *item;
+    AudioDeviceList *prev = NULL;
+    for (item = *list; item != NULL; item = item->next) {
+        item->alive = SDL_FALSE;
+    }
+
+    build_device_list(iscapture, build_device_change_list, list);
+
+    /* free items in the list that aren't still alive. */
+    item = *list;
+    while (item != NULL) {
+        AudioDeviceList *next = item->next;
+        if (item->alive) {
+            prev = item;
+        } else {
+            SDL_RemoveAudioDevice(iscapture, (void *) ((size_t) item->devid));
+            if (prev) {
+                prev->next = item->next;
+            } else {
+                *list = item->next;
+            }
+            SDL_free(item);
+        }
+        item = next;
+    }
+}
+
+/* this is called when the system's list of available audio devices changes. */
+static OSStatus
+device_list_changed(AudioObjectID systemObj, UInt32 num_addr, const AudioObjectPropertyAddress *addrs, void *data)
+{
+    reprocess_device_list(SDL_TRUE, &capture_devs);
+    reprocess_device_list(SDL_FALSE, &output_devs);
+    return 0;
+}
+#endif
+
+
+static int open_playback_devices = 0;
+static int open_capture_devices = 0;
+
+#if !MACOSX_COREAUDIO
+
+static void interruption_begin(_THIS)
+{
+    if (this != NULL && this->hidden->audioQueue != NULL) {
+        this->hidden->interrupted = SDL_TRUE;
+        AudioQueuePause(this->hidden->audioQueue);
+    }
+}
+
+static void interruption_end(_THIS)
+{
+    if (this != NULL && this->hidden != NULL && this->hidden->audioQueue != NULL
+    && this->hidden->interrupted
+    && AudioQueueStart(this->hidden->audioQueue, NULL) == AVAudioSessionErrorCodeNone) {
+        this->hidden->interrupted = SDL_FALSE;
+    }
+}
+
+@interface SDLInterruptionListener : NSObject
+
+@property (nonatomic, assign) SDL_AudioDevice *device;
+
+@end
+
+@implementation SDLInterruptionListener
+
+- (void)audioSessionInterruption:(NSNotification *)note
+{
+    @synchronized (self) {
+        NSNumber *type = note.userInfo[AVAudioSessionInterruptionTypeKey];
+        if (type.unsignedIntegerValue == AVAudioSessionInterruptionTypeBegan) {
+            interruption_begin(self.device);
+        } else {
+            interruption_end(self.device);
+        }
+    }
+}
+
+- (void)applicationBecameActive:(NSNotification *)note
+{
+    @synchronized (self) {
+        interruption_end(self.device);
+    }
+}
+
+@end
+
+static BOOL update_audio_session(_THIS, SDL_bool open)
+{
+    @autoreleasepool {
+        AVAudioSession *session = [AVAudioSession sharedInstance];
+        NSNotificationCenter *center = [NSNotificationCenter defaultCenter];
+        /* Set category to ambient by default so that other music continues playing. */
+        NSString *category = AVAudioSessionCategoryAmbient;
+        NSError *err = nil;
+
+        if (open_playback_devices && open_capture_devices) {
+            category = AVAudioSessionCategoryPlayAndRecord;
+        } else if (open_capture_devices) {
+            category = AVAudioSessionCategoryRecord;
+        } else {
+            const char *hint = SDL_GetHint(SDL_HINT_AUDIO_CATEGORY);
+            if (hint) {
+                if (SDL_strcasecmp(hint, "AVAudioSessionCategoryAmbient") == 0) {
+                    category = AVAudioSessionCategoryAmbient;
+                } else if (SDL_strcasecmp(hint, "AVAudioSessionCategorySoloAmbient") == 0) {
+                    category = AVAudioSessionCategorySoloAmbient;
+                } else if (SDL_strcasecmp(hint, "AVAudioSessionCategoryPlayback") == 0 ||
+                           SDL_strcasecmp(hint, "playback") == 0) {
+                    category = AVAudioSessionCategoryPlayback;
+                }
+            }
+        }
+
+        if (![session setCategory:category error:&err]) {
+            NSString *desc = err.description;
+            SDL_SetError("Could not set Audio Session category: %s", desc.UTF8String);
+            return NO;
+        }
+
+        if (open && (open_playback_devices + open_capture_devices) == 1) {
+            if (![session setActive:YES error:&err]) {
+                NSString *desc = err.description;
+                SDL_SetError("Could not activate Audio Session: %s", desc.UTF8String);
+                return NO;
+            }
+        } else if (!open_playback_devices && !open_capture_devices) {
+            [session setActive:NO error:nil];
+        }
+
+        if (open) {
+            SDLInterruptionListener *listener = [SDLInterruptionListener new];
+            listener.device = this;
+
+            [center addObserver:listener
+                       selector:@selector(audioSessionInterruption:)
+                           name:AVAudioSessionInterruptionNotification
+                         object:session];
+
+            /* An interruption end notification is not guaranteed to be sent if
+             we were previously interrupted... resuming if needed when the app
+             becomes active seems to be the way to go. */
+            [center addObserver:listener
+                       selector:@selector(applicationBecameActive:)
+                           name:UIApplicationDidBecomeActiveNotification
+                         object:session];
+
+            [center addObserver:listener
+                       selector:@selector(applicationBecameActive:)
+                           name:UIApplicationWillEnterForegroundNotification
+                         object:session];
+
+            this->hidden->interruption_listener = CFBridgingRetain(listener);
+        } else {
+            if (this->hidden->interruption_listener != NULL) {
+                SDLInterruptionListener *listener = nil;
+                listener = (SDLInterruptionListener *) CFBridgingRelease(this->hidden->interruption_listener);
+                [center removeObserver:listener];
+                @synchronized (listener) {
+                    listener.device = NULL;
+                }
+            }
+        }
+    }
+
+    return YES;
+}
+#endif
+
+
+/* The AudioQueue callback */
+static void
+outputCallback(void *inUserData, AudioQueueRef inAQ, AudioQueueBufferRef inBuffer)
+{
+    SDL_AudioDevice *this = (SDL_AudioDevice *) inUserData;
+    SDL_assert(inBuffer->mAudioDataBytesCapacity == this->hidden->bufferSize);
+    SDL_memcpy(inBuffer->mAudioData, this->hidden->buffer, this->hidden->bufferSize);
+    SDL_memset(this->hidden->buffer, '\0', this->hidden->bufferSize);  /* zero out in case we have to fill again without new data. */
+    inBuffer->mAudioDataByteSize = this->hidden->bufferSize;
+    AudioQueueEnqueueBuffer(this->hidden->audioQueue, inBuffer, 0, NULL);
+    this->hidden->refill = SDL_TRUE;
+}
+
+static Uint8 *
+COREAUDIO_GetDeviceBuf(_THIS)
+{
+    return this->hidden->buffer;
+}
+
+static void
+COREAUDIO_WaitDevice(_THIS)
+{
+    while (SDL_AtomicGet(&this->enabled) && !this->hidden->refill) {
+        CFRunLoopRunInMode(kCFRunLoopDefaultMode, 0.10, 1);
+    }
+    this->hidden->refill = SDL_FALSE;
+}
+
+static void
+inputCallback(void *inUserData, AudioQueueRef inAQ, AudioQueueBufferRef inBuffer,
+              const AudioTimeStamp *inStartTime, UInt32 inNumberPacketDescriptions,
+              const AudioStreamPacketDescription *inPacketDescs )
+{
+    SDL_AudioDevice *this = (SDL_AudioDevice *) inUserData;
+    if (SDL_AtomicGet(&this->enabled)) {
+        SDL_AudioStream *stream = this->hidden->capturestream;
+        if (SDL_AudioStreamPut(stream, inBuffer->mAudioData, inBuffer->mAudioDataByteSize) == -1) {
+            /* yikes, out of memory or something. I guess drop the buffer. Our WASAPI target kills the device in this case, though */
+        }
+        AudioQueueEnqueueBuffer(this->hidden->audioQueue, inBuffer, 0, NULL);
+        this->hidden->refill = SDL_TRUE;
+    }
+}
+
+static int
+COREAUDIO_CaptureFromDevice(_THIS, void *buffer, int buflen)
+{
+    SDL_AudioStream *stream = this->hidden->capturestream;
+    while (SDL_AtomicGet(&this->enabled)) {
+        const int avail = SDL_AudioStreamAvailable(stream);
+        if (avail > 0) {
+            const int cpy = SDL_min(buflen, avail);
+            SDL_AudioStreamGet(stream, buffer, cpy);
+            return cpy;
+        }
+
+        /* wait for more data, try again. */
+        while (SDL_AtomicGet(&this->enabled) && !this->hidden->refill) {
+            CFRunLoopRunInMode(kCFRunLoopDefaultMode, 0.10, 1);
+        }
+        this->hidden->refill = SDL_FALSE;
+    }
+
+    return 0;  /* not enabled, giving up. */
+}
+
+static void
+COREAUDIO_FlushCapture(_THIS)
+{
+    while (CFRunLoopRunInMode(kCFRunLoopDefaultMode, 0, 1) == kCFRunLoopRunHandledSource) {
+        /* spin. */
+    }
+    this->hidden->refill = SDL_FALSE;
+    SDL_AudioStreamClear(this->hidden->capturestream);
+}
+
+
+#if MACOSX_COREAUDIO
+static const AudioObjectPropertyAddress alive_address =
+{
+    kAudioDevicePropertyDeviceIsAlive,
+    kAudioObjectPropertyScopeGlobal,
+    kAudioObjectPropertyElementMaster
+};
+
+static OSStatus
+device_unplugged(AudioObjectID devid, UInt32 num_addr, const AudioObjectPropertyAddress *addrs, void *data)
+{
+    SDL_AudioDevice *this = (SDL_AudioDevice *) data;
+    SDL_bool dead = SDL_FALSE;
+    UInt32 isAlive = 1;
+    UInt32 size = sizeof (isAlive);
+    OSStatus error;
+
+    if (!SDL_AtomicGet(&this->enabled)) {
+        return 0;  /* already known to be dead. */
+    }
+
+    error = AudioObjectGetPropertyData(this->hidden->deviceID, &alive_address,
+                                       0, NULL, &size, &isAlive);
+
+    if (error == kAudioHardwareBadDeviceError) {
+        dead = SDL_TRUE;  /* device was unplugged. */
+    } else if ((error == kAudioHardwareNoError) && (!isAlive)) {
+        dead = SDL_TRUE;  /* device died in some other way. */
+    }
+
+    if (dead) {
+        SDL_OpenedAudioDeviceDisconnected(this);
+    }
+
+    return 0;
+}
+#endif
+
+static void
+COREAUDIO_CloseDevice(_THIS)
+{
+    const SDL_bool iscapture = this->iscapture;
+
+/* !!! FIXME: what does iOS do when a bluetooth audio device vanishes? Headphones unplugged? */
+/* !!! FIXME: (we only do a "default" device on iOS right now...can we do more?) */
+#if MACOSX_COREAUDIO
+    /* Fire a callback if the device stops being "alive" (disconnected, etc). */
+    AudioObjectRemovePropertyListener(this->hidden->deviceID, &alive_address, device_unplugged, this);
+#endif
+
+#if !MACOSX_COREAUDIO
+    update_audio_session(this, SDL_FALSE);
+#endif
+
+    if (this->hidden->audioQueue) {
+        AudioQueueDispose(this->hidden->audioQueue, 1);
+    }
+
+    if (this->hidden->capturestream) {
+        SDL_FreeAudioStream(this->hidden->capturestream);
+    }
+
+    /* AudioQueueDispose() frees the actual buffer objects. */
+    SDL_free(this->hidden->audioBuffer);
+    SDL_free(this->hidden->buffer);
+    SDL_free(this->hidden);
+
+    if (iscapture) {
+        open_capture_devices--;
+    } else {
+        open_playback_devices--;
+    }
+}
+
+#if MACOSX_COREAUDIO
+static int
+prepare_device(_THIS, void *handle, int iscapture)
+{
+    AudioDeviceID devid = (AudioDeviceID) ((size_t) handle);
+    OSStatus result = noErr;
+    UInt32 size = 0;
+    UInt32 alive = 0;
+    pid_t pid = 0;
+
+    AudioObjectPropertyAddress addr = {
+        0,
+        kAudioObjectPropertyScopeGlobal,
+        kAudioObjectPropertyElementMaster
+    };
+
+    if (handle == NULL) {
+        size = sizeof (AudioDeviceID);
+        addr.mSelector =
+            ((iscapture) ? kAudioHardwarePropertyDefaultInputDevice :
+            kAudioHardwarePropertyDefaultOutputDevice);
+        result = AudioObjectGetPropertyData(kAudioObjectSystemObject, &addr,
+                                            0, NULL, &size, &devid);
+        CHECK_RESULT("AudioHardwareGetProperty (default device)");
+    }
+
+    addr.mSelector = kAudioDevicePropertyDeviceIsAlive;
+    addr.mScope = iscapture ? kAudioDevicePropertyScopeInput :
+                    kAudioDevicePropertyScopeOutput;
+
+    size = sizeof (alive);
+    result = AudioObjectGetPropertyData(devid, &addr, 0, NULL, &size, &alive);
+    CHECK_RESULT
+        ("AudioDeviceGetProperty (kAudioDevicePropertyDeviceIsAlive)");
+
+    if (!alive) {
+        SDL_SetError("CoreAudio: requested device exists, but isn't alive.");
+        return 0;
+    }
+
+    addr.mSelector = kAudioDevicePropertyHogMode;
+    size = sizeof (pid);
+    result = AudioObjectGetPropertyData(devid, &addr, 0, NULL, &size, &pid);
+
+    /* some devices don't support this property, so errors are fine here. */
+    if ((result == noErr) && (pid != -1)) {
+        SDL_SetError("CoreAudio: requested device is being hogged.");
+        return 0;
+    }
+
+    this->hidden->deviceID = devid;
+    return 1;
+}
+#endif
+
+
+/* this all happens in the audio thread, since it needs a separate runloop. */
+static int
+prepare_audioqueue(_THIS)
+{
+    const AudioStreamBasicDescription *strdesc = &this->hidden->strdesc;
+    const int iscapture = this->iscapture;
+    OSStatus result;
+    int i;
+
+    SDL_assert(CFRunLoopGetCurrent() != NULL);
+
+    if (iscapture) {
+        result = AudioQueueNewInput(strdesc, inputCallback, this, CFRunLoopGetCurrent(), kCFRunLoopDefaultMode, 0, &this->hidden->audioQueue);
+        CHECK_RESULT("AudioQueueNewInput");
+    } else {
+        result = AudioQueueNewOutput(strdesc, outputCallback, this, CFRunLoopGetCurrent(), kCFRunLoopDefaultMode, 0, &this->hidden->audioQueue);
+        CHECK_RESULT("AudioQueueNewOutput");
+    }
+
+#if MACOSX_COREAUDIO
+{
+    const AudioObjectPropertyAddress prop = {
+        kAudioDevicePropertyDeviceUID,
+        iscapture ? kAudioDevicePropertyScopeInput : kAudioDevicePropertyScopeOutput,
+        kAudioObjectPropertyElementMaster
+    };
+    CFStringRef devuid;
+    UInt32 devuidsize = sizeof (devuid);
+    result = AudioObjectGetPropertyData(this->hidden->deviceID, &prop, 0, NULL, &devuidsize, &devuid);
+    CHECK_RESULT("AudioObjectGetPropertyData (kAudioDevicePropertyDeviceUID)");
+    result = AudioQueueSetProperty(this->hidden->audioQueue, kAudioQueueProperty_CurrentDevice, &devuid, devuidsize);
+    CHECK_RESULT("AudioQueueSetProperty (kAudioQueueProperty_CurrentDevice)");
+
+    /* !!! FIXME: what does iOS do when a bluetooth audio device vanishes? Headphones unplugged? */
+    /* !!! FIXME: (we only do a "default" device on iOS right now...can we do more?) */
+    /* Fire a callback if the device stops being "alive" (disconnected, etc). */
+    AudioObjectAddPropertyListener(this->hidden->deviceID, &alive_address, device_unplugged, this);
+}
+#endif
+
+    /* Make sure we can feed the device a minimum amount of time */
+    double MINIMUM_AUDIO_BUFFER_TIME_MS = 15.0;
+#if defined(__IPHONEOS__)
+    if (floor(NSFoundationVersionNumber) <= NSFoundationVersionNumber_iOS_7_1) {
+        /* Older iOS hardware, use 40 ms as a minimum time */
+        MINIMUM_AUDIO_BUFFER_TIME_MS = 40.0;
+    }
+#endif
+    const double msecs = (this->spec.samples / ((double) this->spec.freq)) * 1000.0;
+    int numAudioBuffers = 2;
+    if (msecs < MINIMUM_AUDIO_BUFFER_TIME_MS) {  /* use more buffers if we have a VERY small sample set. */
+        numAudioBuffers = ((int)SDL_ceil(MINIMUM_AUDIO_BUFFER_TIME_MS / msecs) * 2);
+    }
+
+    this->hidden->numAudioBuffers = numAudioBuffers;
+    this->hidden->audioBuffer = SDL_calloc(1, sizeof (AudioQueueBufferRef) * numAudioBuffers);
+    if (this->hidden->audioBuffer == NULL) {
+        SDL_OutOfMemory();
+        return 0;
+    }
+
+#if DEBUG_COREAUDIO
+    printf("COREAUDIO: numAudioBuffers == %d\n", numAudioBuffers);
+#endif
+
+    for (i = 0; i < numAudioBuffers; i++) {
+        result = AudioQueueAllocateBuffer(this->hidden->audioQueue, this->spec.size, &this->hidden->audioBuffer[i]);
+        CHECK_RESULT("AudioQueueAllocateBuffer");
+        SDL_memset(this->hidden->audioBuffer[i]->mAudioData, this->spec.silence, this->hidden->audioBuffer[i]->mAudioDataBytesCapacity);
+        this->hidden->audioBuffer[i]->mAudioDataByteSize = this->hidden->audioBuffer[i]->mAudioDataBytesCapacity;
+        result = AudioQueueEnqueueBuffer(this->hidden->audioQueue, this->hidden->audioBuffer[i], 0, NULL);
+        CHECK_RESULT("AudioQueueEnqueueBuffer");
+    }
+
+    result = AudioQueueStart(this->hidden->audioQueue, NULL);
+    CHECK_RESULT("AudioQueueStart");
+
+    /* We're running! */
+    return 1;
+}
+
+static void
+COREAUDIO_ThreadInit(_THIS)
+{
+    const int rc = prepare_audioqueue(this);
+    if (!rc) {
+        /* !!! FIXME: do this in RunAudio, and maybe block OpenDevice until ThreadInit finishes, too, to report an opening error */
+        SDL_OpenedAudioDeviceDisconnected(this);  /* oh well. */
+    }
+}
+
+static void
+COREAUDIO_PrepareToClose(_THIS)
+{
+    /* run long enough to queue some silence, so we know our actual audio
+       has been played */
+    CFRunLoopRunInMode(kCFRunLoopDefaultMode, (((this->spec.samples * 1000) / this->spec.freq) * 2) / 1000.0f, 0);
+    AudioQueueStop(this->hidden->audioQueue, 1);
+}
+
+static int
+COREAUDIO_OpenDevice(_THIS, void *handle, const char *devname, int iscapture)
+{
+    AudioStreamBasicDescription *strdesc;
+    SDL_AudioFormat test_format = SDL_FirstAudioFormat(this->spec.format);
+    int valid_datatype = 0;
+
+    /* Initialize all variables that we clean on shutdown */
+    this->hidden = (struct SDL_PrivateAudioData *)
+        SDL_malloc((sizeof *this->hidden));
+    if (this->hidden == NULL) {
+        return SDL_OutOfMemory();
+    }
+    SDL_zerop(this->hidden);
+
+    strdesc = &this->hidden->strdesc;
+
+    if (iscapture) {
+        open_capture_devices++;
+    } else {
+        open_playback_devices++;
+    }
+
+#if !MACOSX_COREAUDIO
+    if (!update_audio_session(this, SDL_TRUE)) {
+        return -1;
+    }
+
+    /* Stop CoreAudio from doing expensive audio rate conversion */
+    @autoreleasepool {
+        AVAudioSession* session = [AVAudioSession sharedInstance];
+        [session setPreferredSampleRate:this->spec.freq error:nil];
+        this->spec.freq = (int)session.sampleRate;
+    }
+#endif
+
+    /* Setup a AudioStreamBasicDescription with the requested format */
+    SDL_zerop(strdesc);
+    strdesc->mFormatID = kAudioFormatLinearPCM;
+    strdesc->mFormatFlags = kLinearPCMFormatFlagIsPacked;
+    strdesc->mChannelsPerFrame = this->spec.channels;
+    strdesc->mSampleRate = this->spec.freq;
+    strdesc->mFramesPerPacket = 1;
+
+    while ((!valid_datatype) && (test_format)) {
+        this->spec.format = test_format;
+        /* Just a list of valid SDL formats, so people don't pass junk here. */
+        switch (test_format) {
+        case AUDIO_U8:
+        case AUDIO_S8:
+        case AUDIO_U16LSB:
+        case AUDIO_S16LSB:
+        case AUDIO_U16MSB:
+        case AUDIO_S16MSB:
+        case AUDIO_S32LSB:
+        case AUDIO_S32MSB:
+        case AUDIO_F32LSB:
+        case AUDIO_F32MSB:
+            valid_datatype = 1;
+            strdesc->mBitsPerChannel = SDL_AUDIO_BITSIZE(this->spec.format);
+            if (SDL_AUDIO_ISBIGENDIAN(this->spec.format))
+                strdesc->mFormatFlags |= kLinearPCMFormatFlagIsBigEndian;
+
+            if (SDL_AUDIO_ISFLOAT(this->spec.format))
+                strdesc->mFormatFlags |= kLinearPCMFormatFlagIsFloat;
+            else if (SDL_AUDIO_ISSIGNED(this->spec.format))
+                strdesc->mFormatFlags |= kLinearPCMFormatFlagIsSignedInteger;
+            break;
+        }
+    }
+
+    if (!valid_datatype) {      /* shouldn't happen, but just in case... */
+        return SDL_SetError("Unsupported audio format");
+    }
+
+    strdesc->mBytesPerFrame = strdesc->mBitsPerChannel * strdesc->mChannelsPerFrame / 8;
+    strdesc->mBytesPerPacket = strdesc->mBytesPerFrame * strdesc->mFramesPerPacket;
+
+#if MACOSX_COREAUDIO
+    if (!prepare_device(this, handle, iscapture)) {
+        return -1;
+    }
+#endif
+
+    /* Calculate the final parameters for this audio specification */
+    SDL_CalculateAudioSpec(&this->spec);
+
+    if (iscapture) {
+        this->hidden->capturestream = SDL_NewAudioStream(this->spec.format, this->spec.channels, this->spec.freq, this->spec.format, this->spec.channels, this->spec.freq);
+        if (!this->hidden->capturestream) {
+            return -1;  /* already set SDL_Error */
+        }
+    } else {
+        this->hidden->bufferSize = this->spec.size;
+        this->hidden->buffer = SDL_malloc(this->hidden->bufferSize);
+        if (this->hidden->buffer == NULL) {
+            return SDL_OutOfMemory();
+        }
+    }
+
+    return 0;
+}
+
+static void
+COREAUDIO_Deinitialize(void)
+{
+#if MACOSX_COREAUDIO
+    AudioObjectRemovePropertyListener(kAudioObjectSystemObject, &devlist_address, device_list_changed, NULL);
+    free_audio_device_list(&capture_devs);
+    free_audio_device_list(&output_devs);
+#endif
+}
+
+static int
+COREAUDIO_Init(SDL_AudioDriverImpl * impl)
+{
+    /* Set the function pointers */
+    impl->OpenDevice = COREAUDIO_OpenDevice;
+    impl->CloseDevice = COREAUDIO_CloseDevice;
+    impl->Deinitialize = COREAUDIO_Deinitialize;
+    impl->ThreadInit = COREAUDIO_ThreadInit;
+    impl->WaitDevice = COREAUDIO_WaitDevice;
+    impl->GetDeviceBuf = COREAUDIO_GetDeviceBuf;
+    impl->PrepareToClose = COREAUDIO_PrepareToClose;
+    impl->CaptureFromDevice = COREAUDIO_CaptureFromDevice;
+    impl->FlushCapture = COREAUDIO_FlushCapture;
+
+#if MACOSX_COREAUDIO
+    impl->DetectDevices = COREAUDIO_DetectDevices;
+    AudioObjectAddPropertyListener(kAudioObjectSystemObject, &devlist_address, device_list_changed, NULL);
+#else
+    impl->OnlyHasDefaultOutputDevice = 1;
+    impl->OnlyHasDefaultCaptureDevice = 1;
+#endif
+
+    impl->HasCaptureSupport = 1;
+
+    return 1;   /* this audio target is available. */
+}
+
+AudioBootStrap COREAUDIO_bootstrap = {
+    "coreaudio", "CoreAudio", COREAUDIO_Init, 0
+};
+
+#endif /* SDL_AUDIO_DRIVER_COREAUDIO */
+
+/* vi: set ts=4 sw=4 expandtab: */