tstatus/alsa.c

/* see LICENSE file for details on license */
#include <unistd.h>
#include <fcntl.h>
#include <time.h>
#include <alsa/asoundlib.h>
#include <alloca.h>

#include "module.h"

int audio_volume(long *outvol) {
	int ret = 0;
	snd_mixer_t *handle;
	snd_mixer_elem_t *elem;
	snd_mixer_selem_id_t *sid;

	static const char *mix_name = "Master";
	static const char *card = "default";
	static int mix_index = 0;

	long minv, maxv;

	snd_mixer_selem_id_alloca(&sid);

	snd_mixer_selem_id_set_index(sid, mix_index);
	snd_mixer_selem_id_set_name(sid, mix_name);

	if((snd_mixer_open(&handle, 0)) < 0)
		return -1;

	if((snd_mixer_attach(handle, card)) < 0) {
		snd_mixer_close(handle);
		return -1;
	}

	if((snd_mixer_selem_register(handle, NULL, NULL)) < 0) {
		snd_mixer_close(handle);
		return -1;
	}

	ret = snd_mixer_load(handle);
	if(ret < 0) {
		snd_mixer_close(handle);
		return -1;
	}

	elem = snd_mixer_find_selem(handle, sid);
	if(!elem) {
		snd_mixer_close(handle);
		return -1;
	}

	snd_mixer_selem_get_playback_volume_range (elem, &minv, &maxv);

	if(snd_mixer_selem_get_playback_volume(elem, 0, outvol) < 0) {
		snd_mixer_close(handle);
		return -1;
	}

	/* make the value bound to 100 */
	*outvol -= minv;
	maxv -= minv;
	minv = 0;
	*outvol = 100 * (*outvol) / maxv;

	snd_mixer_close(handle);
	return 0;
}

int alsa_update(struct module *module) {
	long vol = -1;
	audio_volume(&vol);
	snprintf((char *)&module->buffer, MODULE_BUFFER_LEN, "%li", vol);

	return 0;
}