osx_write.c: Rename 'output' to 'audio_unit', add documentation

[paraslash.git] / osx_write.c

diff --git a/osx_write.c b/osx_write.c
index 287601c7639b5bdf4d393988de56fdc308cb9871..153ae3d656bdfff144f048e584430968dc8b3ea2 100644 (file)
--- a/osx_write.c
+++ b/osx_write.c
@@ -37,40 +37,40 @@
 #include <CoreAudio/CoreAudio.h>
 #include <AudioUnit/AudioUnit.h>
 #include <AudioToolbox/DefaultAudioOutput.h>
+
+/** describes one input buffer for the osx writer */
 struct osx_buffer {
+       /** pointer to the beginning of the buffer */
        float *buffer;
+       /** the size of this buffer */
        long size;
-       float *ptr; /* Where in the buffer are we? */
+       /* current position in the buffer */
+       float *ptr;
+       /** number of floats not yet consuned */
        long remaining;
+       /** pointer to the next audio buffer */
        struct osx_buffer *next;
 };
-typedef struct osx_buffer osx_buffer; /* FIXME */
 
 struct private_osx_write_data {
-       long size;
-       short *ptr;
-       AudioUnit output;
+       /** the main control structure for audio data manipulation */
+       AudioUnit audio_unit;
+       /** non-zero if playback has started */
        char play;
-       osx_buffer *from; /* Current buffers */
-       osx_buffer *to;
+       /** callback reads audio data from this buffer */
+       struct osx_buffer *from;
+       /* the post_select writes audio data here */
+       struct osx_buffer *to;
+       /** sample rate of the current audio stream */
        unsigned samplerate;
+       /** number of channels of the current audio stream */
        unsigned channels;
 };
 
-
-/*
- * Tried with 3 buffers, but then any little window move is sufficient to
- * stop the sound (OK, on a G3 400 with a Public Beta. Perhaps now we can
- * go down to 2 buffers). With 16 buffers we have 1.5 seconds music
- * buffered (or, if you're pessimistic, 1.5 seconds latency). Note 0
- * buffers don't work much further than the Bus error.
- */
-#define NUMBER_BUFFERS 2
-
 static void destroy_buffers(struct private_osx_write_data *powd)
 {
-       osx_buffer *ptr;
-       osx_buffer *ptr2;
+       struct osx_buffer *ptr;
+       struct osx_buffer *ptr2;
        ptr = powd->to->next;
        powd->to->next = NULL;
        while (ptr) {
@@ -81,14 +81,16 @@ static void destroy_buffers(struct private_osx_write_data *powd)
        }
 }
 
-static void init_buffers(struct private_osx_write_data *powd)
+static void init_buffers(struct writer_node *wn)
 {
+       struct private_osx_write_data *powd = wn->private_data;
+       struct osx_write_args_info *conf = wn->conf;
+       struct osx_buffer **ptrptr;
        int i;
 
-       osx_buffer ** ptrptr;
        ptrptr = &powd->to;
-       for (i = 0; i < NUMBER_BUFFERS; i++) {
-               *ptrptr = malloc(sizeof(osx_buffer));
+       for (i = 0; i < conf->numbuffers_arg; i++) {
+               *ptrptr = malloc(sizeof(struct osx_buffer));
                (*ptrptr)->size = 0;
                (*ptrptr)->remaining = 0;
                (*ptrptr)->buffer = NULL;
@@ -97,7 +99,7 @@ static void init_buffers(struct private_osx_write_data *powd)
        *ptrptr = powd->from = powd->to;
 }
 
-static void fill_buffer(osx_buffer *b, short *source, long size)
+static void fill_buffer(struct osx_buffer *b, short *source, long size)
 {
        float *dest;
 
@@ -189,13 +191,11 @@ static int osx_write_open(struct writer_node *wn)
        if (!comp)
                goto e0;
        ret = -E_OPEN_COMP;
-       if (OpenAComponent(comp, &powd->output))
+       if (OpenAComponent(comp, &powd->audio_unit))
                goto e0;
        ret = -E_UNIT_INIT;
-       if (AudioUnitInitialize(powd->output))
+       if (AudioUnitInitialize(powd->audio_unit))
                goto e1;
-       powd->size = 0;
-       powd->ptr = NULL;
        powd->play = 0;
        /* Hmmm, let's choose PCM format */
        /* We tell the Output Unit what format we're going to supply data to it.
@@ -225,13 +225,13 @@ static int osx_write_open(struct writer_node *wn)
        /* one of the most constant constants of the whole computer history */
        format.mBitsPerChannel = sizeof(float) * 8;
        ret = -E_STREAM_FORMAT;
-       if (AudioUnitSetProperty(powd->output, kAudioUnitProperty_StreamFormat,
+       if (AudioUnitSetProperty(powd->audio_unit, kAudioUnitProperty_StreamFormat,
                        kAudioUnitScope_Input, 0, &format,
                        sizeof(AudioStreamBasicDescription)))
                goto e2;
-       init_buffers(powd);
+       init_buffers(wn);
        ret = -E_ADD_CALLBACK;
-       if (AudioUnitSetProperty(powd->output, kAudioUnitProperty_SetRenderCallback,
+       if (AudioUnitSetProperty(powd->audio_unit, kAudioUnitProperty_SetRenderCallback,
                        kAudioUnitScope_Input, 0, &inputCallback,
                        sizeof(inputCallback)) < 0)
                goto e3;
@@ -239,9 +239,9 @@ static int osx_write_open(struct writer_node *wn)
 e3:
        destroy_buffers(powd);
 e2:
-       AudioUnitUninitialize(powd->output);
+       AudioUnitUninitialize(powd->audio_unit);
 e1:
-       CloseComponent(powd->output);
+       CloseComponent(powd->audio_unit);
 e0:
        return ret;
 }
@@ -266,9 +266,9 @@ static void osx_write_close(struct writer_node *wn)
        struct private_osx_write_data *powd = wn->private_data;
 
        PARA_INFO_LOG("closing writer node %p\n", wn);
-       AudioOutputUnitStop(powd->output);
-       AudioUnitUninitialize(powd->output);
-       CloseComponent(powd->output);
+       AudioOutputUnitStop(powd->audio_unit);
+       AudioUnitUninitialize(powd->audio_unit);
+       CloseComponent(powd->audio_unit);
        destroy_buffers(powd);
        free(powd);
 }
@@ -298,7 +298,7 @@ static int osx_write_post_select(__a_unused struct sched *s,
        powd->to = powd->to->next;
        wn->written = *wng->loaded;
        if (!powd->play) {
-               if (AudioOutputUnitStart(powd->output))
+               if (AudioOutputUnitStart(powd->audio_unit))
                        return -E_UNIT_START;
                powd->play = 1;
        }
@@ -332,6 +332,7 @@ min_delay:
        return 1;
 }
 
+/** the init function of the osx writer */
 void osx_write_init(struct writer *w)
 {
        w->open = osx_write_open;