-Add: digitized sound output for old Mac OS X implementation

using CoreAudio / AudioUnits

config.lib

@@ -947,6 +947,7 @@ make_cflags_and_ldflags() {
 		if [ -z "$sdl2_config" ] && [ -z "$sdl_config" ] ; then
 			LDFLAGS="$LDFLAGS -Wl,-framework,ApplicationServices"
 			LDFLAGS="$LDFLAGS -Wl,-framework,Carbon"
+			LDFLAGS="$LDFLAGS -Wl,-framework,CoreAudio"
 		fi
 
 		if [ "$enable_universal" = "0" ]; then

source.list

@@ -26,7 +26,11 @@ audio/midi_atari.c
 				#if SDL2
 					audio/dsp_sdl.c
 				#else
+					#if OSX
+					audio/dsp_osx.c
+					#else
 					audio/dsp_none.c
+					#endif
 				#endif
 			#endif
 		#endif

src/audio/dsp_osx.c

@@ -0,0 +1,169 @@
+/* AudioUnit */
+
+#if defined(__ALTIVEC__) && !defined(MAC_OS_X_VERSION_10_5)
+/* to circumvent a bug in Mac OS X 10.4 SDK */
+#define vector __vector
+#include <CoreServices/CoreServices.h>
+#undef vector
+#endif
+#include <AudioUnit/AudioUnit.h>
+
+#include "types.h"
+#include "dsp.h"
+#include "../os/error.h"
+#include "../os/endian.h"
+
+static AudioUnit outputAudioUnit;
+
+uint32 remaining_len = 0;
+const uint8 * current_data;
+
+static OSStatus audioCallback(void                       *inRefCon,
+                              AudioUnitRenderActionFlags *ioActionFlags,
+                              const AudioTimeStamp       *inTimeStamp,
+                              UInt32                     inBusNumber,
+                              UInt32                     inNumberFrames,
+                              AudioBufferList            *ioData)
+{
+	UInt32 i, len;
+	char * ptr;
+
+	Debug("audioCallback(%p, %p, %p, %u, %u, %p)\n",
+	      inRefCon, ioActionFlags, inTimeStamp, (unsigned)inBusNumber, (unsigned)inNumberFrames, ioData);
+	for (i = 0; i < ioData->mNumberBuffers; i++) {
+		len = ioData->mBuffers[i].mDataByteSize;
+		ptr = ioData->mBuffers[i].mData;
+		if (remaining_len == 0 || i > 0) {
+			memset(ptr, 0x80, len);
+		} else if (remaining_len < len) {
+			memcpy(ptr, current_data, remaining_len);
+			ptr += remaining_len;
+			len -= remaining_len;
+			remaining_len = 0;
+			memset(ptr, 0x80, len);
+		} else {
+			memcpy(ptr, current_data, len);
+			remaining_len -= len;
+			current_data += len;
+		}
+	}
+	return noErr;
+}
+
+void DSP_Play(const uint8 *data)
+{
+	AudioStreamBasicDescription format;
+	UInt32 size = sizeof(format);
+	OSStatus err;
+	uint32 len;
+
+	DSP_Stop();
+
+	format.mChannelsPerFrame = 1;	/* MONO */
+	/*format.mChannelsPerFrame = 2;*/	/* STEREO */
+	format.mFormatID = kAudioFormatLinearPCM;
+	format.mFormatFlags = kLinearPCMFormatFlagIsPacked | kLinearPCMFormatFlagIsBigEndian;
+	format.mBitsPerChannel = 8;
+	format.mFramesPerPacket = 1;
+	format.mBytesPerFrame = format.mBitsPerChannel * format.mChannelsPerFrame / 8;
+	format.mBytesPerPacket = format.mBytesPerFrame * format.mFramesPerPacket;
+
+	data += READ_LE_UINT16(data + 20);  /* skip Create Voice File header */
+	len = (READ_LE_UINT32(data) >> 8) - 2;
+	data += 4;
+
+	format.mSampleRate = 1000000 / (256 - data[0]);
+	data += 2;
+
+    /* Set the input format of the audio unit. */
+	err = AudioUnitSetProperty(outputAudioUnit,
+					kAudioUnitProperty_StreamFormat, kAudioUnitScope_Input,
+					0, &format, sizeof(format));
+	if (err != noErr) Warning("AudioUnitSetProperty(kAudioUnitProperty_StreamFormat) failed\n");
+
+	current_data = data;
+	remaining_len = len;
+
+	err = AudioOutputUnitStart (outputAudioUnit);
+	if (err != noErr) Warning("AudioOutputUnitStart() failed\n");
+}
+
+void DSP_Stop(void)
+{
+	OSStatus result = AudioOutputUnitStop (outputAudioUnit);
+	if (result != noErr) Warning("AudioOutputUnitStop() failed\n");
+}
+
+uint8 DSP_GetStatus(void)
+{
+	if (remaining_len > 0) return 2;	/* playing */
+	return 0;	/* not playing */
+}
+
+bool DSP_Init(void)
+{
+	OSStatus result = noErr;
+	Component comp;
+	ComponentDescription desc;
+	struct AURenderCallbackStruct callback;
+
+	/* Locate the default output audio unit */
+	desc.componentType = kAudioUnitType_Output;
+	desc.componentSubType = kAudioUnitSubType_DefaultOutput;
+	desc.componentManufacturer = kAudioUnitManufacturer_Apple;
+	desc.componentFlags = 0;
+	desc.componentFlagsMask = 0;
+
+	comp = FindNextComponent (NULL, &desc);
+	if (comp == NULL) {
+		Warning("Failed to start CoreAudio: FindNextComponent returned NULL\n");
+		return false;
+	}
+
+	result = OpenAComponent (comp, &outputAudioUnit);
+	if (result != noErr) {
+		Warning("OpenAComponent() failed\n");
+		return false;
+	}
+	result = AudioUnitInitialize (outputAudioUnit);
+	if (result != noErr) {
+		Warning("AudioUnitInitialize() failed\n");
+		return false;
+	}
+
+	/* Set the audio callback */
+	callback.inputProc = audioCallback;
+	callback.inputProcRefCon = NULL;
+	result = AudioUnitSetProperty(outputAudioUnit,
+			kAudioUnitProperty_SetRenderCallback, kAudioUnitScope_Input,
+			0, &callback, sizeof(callback));
+	if (result != noErr) {
+		Warning("AudioUnitSetProperty(kAudioUnitProperty_SetRenderCallback) failed\n");
+		return false;
+	}
+
+	return true;
+}
+
+void DSP_Uninit(void)
+{
+	OSStatus result = noErr;
+	struct AURenderCallbackStruct callback;
+
+	DSP_Stop();
+
+	/* Remove the input callback */
+	callback.inputProc = 0;
+	callback.inputProcRefCon = 0;
+	result = AudioUnitSetProperty(outputAudioUnit,
+			kAudioUnitProperty_SetRenderCallback, kAudioUnitScope_Input,
+			0, &callback, sizeof(callback));
+	if (result != noErr) {
+		Warning("AudioUnitSetProperty(kAudioUnitProperty_SetInputCallback) failed\n");
+	}
+
+	result = CloseComponent(outputAudioUnit);
+	if (result != noErr) {
+		Warning("CloseComponent() failed\n");
+	}
+}

src/audio/midi_osx.c

@@ -11,6 +11,7 @@
 #include <AudioToolbox/AudioToolbox.h>
 #include "types.h"
 #include "midi.h"
+#include "../os/error.h"
 
 #if defined(AUDIO_TOOLBOX_VERSION) && (AUDIO_TOOLBOX_VERSION >= 0x0105)
 /* Use the new functions in favor of deprecated ones from OS X 10.5 onward */