Audio support on Linux

[mehlon]

Currently there is no devaudio code for Linux in /emu/Linux/
Running padsp emu on Manjaro Linux gives Segmentation fault (core dumped).

[henesy]

http://www.9paste.net/qrstuv/audio-pulse.c (thanks qrstuv)

[henesy]

qrstuv (IRC): add PULSELIBS= -lpulse-simple to the mkfile
[12:11 PM] BOT qrstuv (IRC): and env AUDIOLIBS= $PULSELIBS and dev audio audio-pulse to the emu file

[henesy]

audio-pulse.c inlined:

#include "dat.h"
#include "fns.h"
#include "error.h"
#include "audio.h"
#include <pulse/simple.h>
#include <pulse/error.h>

enum {
	Audio_Mic_Val,
	Audio_Linein_Val,

	Audio_Speaker_Val,
	Audio_Headphone_Val,
	Audio_Lineout_Val,

	Audio_Pcm_Val,
	Audio_Ulaw_Val,
	Audio_Alaw_Val,
};

#include "audio-tbls.c"

static pa_simple *pa;
static Audio_t av;
static QLock palock;

static int
choosefmt(Audio_d *i)
{
	switch(i->bits) {
	case 8:
		switch(i->enc) {
		case Audio_Alaw_Val:
			return PA_SAMPLE_ALAW;
		case Audio_Ulaw_Val:
			return PA_SAMPLE_ULAW;
		case Audio_Pcm_Val:
			return PA_SAMPLE_U8;
		}
		break;
	case 16:
		if(i->enc == Audio_Pcm_Val)
			return PA_SAMPLE_S16LE;
		break;
	}
	return -1;
}

static int
mkspec(pa_sample_spec *spec, Audio_t *info)
{
	spec->channels = info->out.chan;
	spec->rate = info->out.rate;
	if((spec->format = choosefmt(&info->out)) < 0)
		return -1;
	return 0;
}

Audio_t*
getaudiodev(void)
{
	return &av;
}

void
audio_file_init(void)
{
	audio_info_init(&av);
}

void
audio_file_open(Chan *c, int omode)
{
	int err;
	pa_sample_spec spec;
	USED(c);

	if(omode == OREAD || omode == ORDWR)
		error("reading isn't implemented");

	qlock(&palock);
	if(waserror()) {
		qunlock(&palock);
		nexterror();
	}

	if(mkspec(&spec, &av) < 0)
		error(Ebadarg);

	if(pa == NULL)
		pa = pa_simple_new(NULL, "emu", PA_STREAM_PLAYBACK, NULL, "emu", &spec, NULL, NULL, &err);
	if(pa == NULL)
		error(pa_strerror(err));

	qunlock(&palock);
	poperror();
}

void
audio_file_close(Chan *c)
{
	USED(c);

	qlock(&palock);
	pa_simple_drain(pa, NULL);
	qunlock(&palock);
}

long
audio_file_read(Chan *c, void *va, long count, vlong offset)
{
	USED(c);
	USED(va);
	USED(count);
	USED(offset);
	error("not implemented");
	return -1;
}

long
audio_file_write(Chan *c, void *va, long count, vlong offset)
{
	int err;
	USED(c);
	USED(offset);

	qlock(&palock);
	if(waserror()) {
		qunlock(&palock);
		nexterror();
	}

	if(pa_simple_write(pa, va, count, &err) < 0)
		error(pa_strerror(err));

	qunlock(&palock);
	poperror();
	return count;
}

long
audio_ctl_write(Chan *c, void *va, long count, vlong offset)
{
	pa_sample_spec spec;
	int err;
	USED(c);
	USED(offset);

	if(!canqlock(&palock))
		error("device busy");
	if(waserror()) {
		qunlock(&palock);
		nexterror();
	}

	if(!audioparse(va, count, &av) || mkspec(&spec, &av) < 0)
		error(Ebadarg);

	if(pa != NULL)
		pa_simple_free(pa);
	pa = pa_simple_new(NULL, "emu", PA_STREAM_PLAYBACK, NULL, "emu", &spec, NULL, NULL, &err);
	if(pa == NULL)
		error(pa_strerror(err));

	qunlock(&palock);
	poperror();
	return count;
}