src/audio/macosx/SDL_coreaudio.c - third_party/sdl - Git at Google

 /*
     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 "SDL_config.h"

 #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,
               AudioUnitRenderActionFlags inActionFlags,
               const AudioTimeStamp * inTimeStamp,
               UInt32 inBusNumber, 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, (char *) buffer + bufferOffset, len);
         ptr = (char *) 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);
 }

 /* vi: set ts=4 sw=4 expandtab: */
	/*
	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 "SDL_config.h"

	#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,
	AudioUnitRenderActionFlags inActionFlags,
	const AudioTimeStamp * inTimeStamp,
	UInt32 inBusNumber, 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, (char *) buffer + bufferOffset, len);
	ptr = (char *) 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);
	}

	/* vi: set ts=4 sw=4 expandtab: */