/*

SDL - Simple DirectMedia Layer

Copyright (C) 1997-2006 Sam Lantinga

This library is free software; you can redistribute it and/or

modify it under the terms of the GNU Lesser General Public

License as published by the Free Software Foundation; either

version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,

but WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU

Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public

License along with this library; if not, write to the Free Software

Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA

Sam Lantinga

slouken@libsdl.org

*/

#include <AudioUnit/AudioUnit.h>

#include "SDL_audio.h"

#include "../SDL_audio_c.h"

#include "../SDL_sysaudio.h"

#include "SDL_coreaudio.h"

/* Audio driver functions */

static int Core_OpenAudio(_THIS, SDL_AudioSpec *spec);

static void Core_WaitAudio(_THIS);

static void Core_PlayAudio(_THIS);

static Uint8 *Core_GetAudioBuf(_THIS);

static void Core_CloseAudio(_THIS);

/* Audio driver bootstrap functions */

static int Audio_Available(void)

{

return(1);

}

static void Audio_DeleteDevice(SDL_AudioDevice *device)

{

SDL_free(device->hidden);

SDL_free(device);

}

static SDL_AudioDevice *Audio_CreateDevice(int devindex)

{

SDL_AudioDevice *this;

/* Initialize all variables that we clean on shutdown */

this = (SDL_AudioDevice *)SDL_malloc(sizeof(SDL_AudioDevice));

if ( this ) {

SDL_memset(this, 0, (sizeof *this));

this->hidden = (struct SDL_PrivateAudioData *)

SDL_malloc((sizeof *this->hidden));

}

if ( (this == NULL) || (this->hidden == NULL) ) {

SDL_OutOfMemory();

if ( this ) {

SDL_free(this);

}

return(0);

}

SDL_memset(this->hidden, 0, (sizeof *this->hidden));

/* Set the function pointers */

this->OpenAudio = Core_OpenAudio;

this->WaitAudio = Core_WaitAudio;

this->PlayAudio = Core_PlayAudio;

this->GetAudioBuf = Core_GetAudioBuf;

this->CloseAudio = Core_CloseAudio;

this->free = Audio_DeleteDevice;

return this;

}

AudioBootStrap COREAUDIO_bootstrap = {

"coreaudio", "Mac OS X CoreAudio",

Audio_Available, Audio_CreateDevice

};

/* The CoreAudio callback */

static OSStatus audioCallback (void *inRefCon,

AudioBuffer *ioData)

{

SDL_AudioDevice *this = (SDL_AudioDevice *)inRefCon;

UInt32 remaining, len;

void *ptr;

/* Only do anything if audio is enabled and not paused */

if ( ! this->enabled || this->paused ) {

SDL_memset(ioData->mData, this->spec.silence, ioData->mDataByteSize);

return 0;

}

/* No SDL conversion should be needed here, ever, since we accept

any input format in OpenAudio, and leave the conversion to CoreAudio.

*/

/*

assert(!this->convert.needed);

assert(this->spec.channels == ioData->mNumberChannels);

*/

remaining = ioData->mDataByteSize;

ptr = ioData->mData;

while (remaining > 0) {

if (bufferOffset >= bufferSize) {

/* Generate the data */

SDL_memset(buffer, this->spec.silence, bufferSize);

SDL_mutexP(this->mixer_lock);

(*this->spec.callback)(this->spec.userdata,

buffer, bufferSize);

SDL_mutexV(this->mixer_lock);

bufferOffset = 0;

}

len = bufferSize - bufferOffset;

if (len > remaining)

len = remaining;

SDL_memcpy(ptr, buffer + bufferOffset, len);

ptr += len;

remaining -= len;

bufferOffset += len;

}

return 0;

}

/* Dummy functions -- we don't use thread-based audio */

void Core_WaitAudio(_THIS)

{

return;

}

void Core_PlayAudio(_THIS)

{

return;

}

Uint8 *Core_GetAudioBuf(_THIS)

{

return(NULL);

}

void Core_CloseAudio(_THIS)

{

OSStatus result;

struct AudioUnitInputCallback callback;

/* stop processing the audio unit */

result = AudioOutputUnitStop (outputAudioUnit);

if (result != noErr) {

SDL_SetError("Core_CloseAudio: AudioOutputUnitStop");

return;

}

/* Remove the input callback */

callback.inputProc = 0;

callback.inputProcRefCon = 0;

result = AudioUnitSetProperty (outputAudioUnit,

kAudioUnitProperty_SetInputCallback,

kAudioUnitScope_Input,

0,

&callback,

sizeof(callback));

if (result != noErr) {

SDL_SetError("Core_CloseAudio: AudioUnitSetProperty (kAudioUnitProperty_SetInputCallback)");

return;

}

result = CloseComponent(outputAudioUnit);

if (result != noErr) {

SDL_SetError("Core_CloseAudio: CloseComponent");

return;

}

SDL_free(buffer);

}

#define CHECK_RESULT(msg) \

if (result != noErr) { \

SDL_SetError("Failed to start CoreAudio: " msg); \

return -1; \

}

int Core_OpenAudio(_THIS, SDL_AudioSpec *spec)

{

OSStatus result = noErr;

Component comp;

ComponentDescription desc;

struct AudioUnitInputCallback callback;

AudioStreamBasicDescription requestedDesc;

/* Setup a AudioStreamBasicDescription with the requested format */

requestedDesc.mFormatID = kAudioFormatLinearPCM;

requestedDesc.mFormatFlags = kLinearPCMFormatFlagIsPacked;

requestedDesc.mChannelsPerFrame = spec->channels;

requestedDesc.mSampleRate = spec->freq;

requestedDesc.mBitsPerChannel = spec->format & 0xFF;

if (spec->format & 0x8000)

requestedDesc.mFormatFlags |= kLinearPCMFormatFlagIsSignedInteger;

if (spec->format & 0x1000)

requestedDesc.mFormatFlags |= kLinearPCMFormatFlagIsBigEndian;

requestedDesc.mFramesPerPacket = 1;

requestedDesc.mBytesPerFrame = requestedDesc.mBitsPerChannel * requestedDesc.mChannelsPerFrame / 8;

requestedDesc.mBytesPerPacket = requestedDesc.mBytesPerFrame * requestedDesc.mFramesPerPacket;

/* Locate the default output audio unit */

desc.componentType = kAudioUnitComponentType;

desc.componentSubType = kAudioUnitSubType_Output;

desc.componentManufacturer = kAudioUnitID_DefaultOutput;

desc.componentFlags = 0;

desc.componentFlagsMask = 0;

comp = FindNextComponent (NULL, &desc);

if (comp == NULL) {

SDL_SetError ("Failed to start CoreAudio: FindNextComponent returned NULL");

return -1;

}

/* Open & initialize the default output audio unit */

result = OpenAComponent (comp, &outputAudioUnit);

CHECK_RESULT("OpenAComponent")

result = AudioUnitInitialize (outputAudioUnit);

CHECK_RESULT("AudioUnitInitialize")

/* Set the input format of the audio unit. */

result = AudioUnitSetProperty (outputAudioUnit,

kAudioUnitProperty_StreamFormat,

kAudioUnitScope_Input,

0,

&requestedDesc,

sizeof (requestedDesc));

CHECK_RESULT("AudioUnitSetProperty (kAudioUnitProperty_StreamFormat)")

/* Set the audio callback */

callback.inputProc = audioCallback;

callback.inputProcRefCon = this;

result = AudioUnitSetProperty (outputAudioUnit,

kAudioUnitProperty_SetInputCallback,

kAudioUnitScope_Input,

0,

&callback,

sizeof(callback));

CHECK_RESULT("AudioUnitSetProperty (kAudioUnitProperty_SetInputCallback)")

/* Calculate the final parameters for this audio specification */

SDL_CalculateAudioSpec(spec);

/* Allocate a sample buffer */

bufferOffset = bufferSize = this->spec.size;

buffer = SDL_malloc(bufferSize);

/* Finally, start processing of the audio unit */

result = AudioOutputUnitStart (outputAudioUnit);

CHECK_RESULT("AudioOutputUnitStart")

/* We're running! */

return(1);

}