+#ifdef HAVE_ALSA
+/***********************************************************************
+ ALSA Driver Interface
+ ***********************************************************************/
+
+/* This driver is available on GNU/Linux. */
+
+static void
+alsa_sound_perror (msg, err)
+ char *msg;
+ int err;
+{
+ error ("%s: %s", msg, snd_strerror (err));
+}
+
+struct alsa_params
+{
+ snd_pcm_t *handle;
+ snd_pcm_hw_params_t *hwparams;
+ snd_pcm_sw_params_t *swparams;
+ snd_pcm_uframes_t period_size;
+};
+
+/* Open device SD. If SD->file is non-null, open that device,
+ otherwise use a default device name. */
+
+static void
+alsa_open (sd)
+ struct sound_device *sd;
+{
+ char *file;
+ struct alsa_params *p;
+ int err;
+
+ /* Open the sound device. Default is "default". */
+ if (sd->file)
+ file = sd->file;
+ else
+ file = DEFAULT_ALSA_SOUND_DEVICE;
+
+ p = xmalloc (sizeof (*p));
+ p->handle = NULL;
+ p->hwparams = NULL;
+ p->swparams = NULL;
+
+ sd->fd = -1;
+ sd->data = p;
+
+
+ err = snd_pcm_open (&p->handle, file, SND_PCM_STREAM_PLAYBACK, 0);
+ if (err < 0)
+ alsa_sound_perror (file, err);
+}
+
+static int
+alsa_period_size (sd)
+ struct sound_device *sd;
+{
+ struct alsa_params *p = (struct alsa_params *) sd->data;
+ int fact = snd_pcm_format_size (sd->format, 1) * sd->channels;
+ return p->period_size * (fact > 0 ? fact : 1);
+}
+
+static void
+alsa_configure (sd)
+ struct sound_device *sd;
+{
+ int val, err, dir;
+ unsigned uval;
+ struct alsa_params *p = (struct alsa_params *) sd->data;
+ snd_pcm_uframes_t buffer_size;
+
+ xassert (p->handle != 0);
+
+ err = snd_pcm_hw_params_malloc (&p->hwparams);
+ if (err < 0)
+ alsa_sound_perror ("Could not allocate hardware parameter structure", err);
+
+ err = snd_pcm_sw_params_malloc (&p->swparams);
+ if (err < 0)
+ alsa_sound_perror ("Could not allocate software parameter structure", err);
+
+ err = snd_pcm_hw_params_any (p->handle, p->hwparams);
+ if (err < 0)
+ alsa_sound_perror ("Could not initialize hardware parameter structure", err);
+
+ err = snd_pcm_hw_params_set_access (p->handle, p->hwparams,
+ SND_PCM_ACCESS_RW_INTERLEAVED);
+ if (err < 0)
+ alsa_sound_perror ("Could not set access type", err);
+
+ val = sd->format;
+ err = snd_pcm_hw_params_set_format (p->handle, p->hwparams, val);
+ if (err < 0)
+ alsa_sound_perror ("Could not set sound format", err);
+
+ uval = sd->sample_rate;
+ err = snd_pcm_hw_params_set_rate_near (p->handle, p->hwparams, &uval, 0);
+ if (err < 0)
+ alsa_sound_perror ("Could not set sample rate", err);
+
+ val = sd->channels;
+ err = snd_pcm_hw_params_set_channels (p->handle, p->hwparams, val);
+ if (err < 0)
+ alsa_sound_perror ("Could not set channel count", err);
+
+ err = snd_pcm_hw_params (p->handle, p->hwparams);
+ if (err < 0)
+ alsa_sound_perror ("Could not set parameters", err);
+
+
+ err = snd_pcm_hw_params_get_period_size (p->hwparams, &p->period_size, &dir);
+ if (err < 0)
+ alsa_sound_perror ("Unable to get period size for playback", err);
+
+ err = snd_pcm_hw_params_get_buffer_size (p->hwparams, &buffer_size);
+ if (err < 0)
+ alsa_sound_perror("Unable to get buffer size for playback", err);
+
+ err = snd_pcm_sw_params_current (p->handle, p->swparams);
+ if (err < 0)
+ alsa_sound_perror ("Unable to determine current swparams for playback",
+ err);
+
+ /* Start the transfer when the buffer is almost full */
+ err = snd_pcm_sw_params_set_start_threshold (p->handle, p->swparams,
+ (buffer_size / p->period_size)
+ * p->period_size);
+ if (err < 0)
+ alsa_sound_perror ("Unable to set start threshold mode for playback", err);
+
+ /* Allow the transfer when at least period_size samples can be processed */
+ err = snd_pcm_sw_params_set_avail_min (p->handle, p->swparams, p->period_size);
+ if (err < 0)
+ alsa_sound_perror ("Unable to set avail min for playback", err);
+
+ /* Align all transfers to 1 period */
+ err = snd_pcm_sw_params_set_xfer_align (p->handle, p->swparams,
+ p->period_size);
+ if (err < 0)
+ alsa_sound_perror ("Unable to set transfer align for playback", err);
+
+ err = snd_pcm_sw_params (p->handle, p->swparams);
+ if (err < 0)
+ alsa_sound_perror ("Unable to set sw params for playback\n", err);
+
+ snd_pcm_hw_params_free (p->hwparams);
+ p->hwparams = NULL;
+ snd_pcm_sw_params_free (p->swparams);
+ p->swparams = NULL;
+
+ err = snd_pcm_prepare (p->handle);
+ if (err < 0)
+ alsa_sound_perror ("Could not prepare audio interface for use", err);
+
+ if (sd->volume > 0)
+ {
+ int chn;
+ snd_mixer_t *handle;
+ snd_mixer_elem_t *e;
+ char *file = sd->file ? sd->file : DEFAULT_ALSA_SOUND_DEVICE;
+
+ if (snd_mixer_open (&handle, 0) >= 0)
+ {
+ if (snd_mixer_attach (handle, file) >= 0
+ && snd_mixer_load (handle) >= 0
+ && snd_mixer_selem_register (handle, NULL, NULL) >= 0)
+ for (e = snd_mixer_first_elem (handle);
+ e;
+ e = snd_mixer_elem_next (e))
+ {
+ if (snd_mixer_selem_has_playback_volume (e))
+ {
+ long pmin, pmax, vol;
+ snd_mixer_selem_get_playback_volume_range (e, &pmin, &pmax);
+ vol = pmin + (sd->volume * (pmax - pmin)) / 100;
+
+ for (chn = 0; chn <= SND_MIXER_SCHN_LAST; chn++)
+ snd_mixer_selem_set_playback_volume (e, chn, vol);
+ }
+ }
+ snd_mixer_close(handle);
+ }
+ }
+}
+
+
+/* Close device SD if it is open. */
+
+static void
+alsa_close (sd)
+ struct sound_device *sd;
+{
+ struct alsa_params *p = (struct alsa_params *) sd->data;
+ if (p)
+ {
+ if (p->hwparams)
+ snd_pcm_hw_params_free (p->hwparams);
+ if (p->swparams)
+ snd_pcm_sw_params_free (p->swparams);
+ if (p->handle)
+ {
+ snd_pcm_drain (p->handle);
+ snd_pcm_close (p->handle);
+ }
+ free (p);
+ }
+}
+
+/* Choose device-dependent format for device SD from sound file S. */
+
+static void
+alsa_choose_format (sd, s)
+ struct sound_device *sd;
+ struct sound *s;
+{
+ struct alsa_params *p = (struct alsa_params *) sd->data;
+ if (s->type == RIFF)
+ {
+ struct wav_header *h = (struct wav_header *) s->header;
+ if (h->precision == 8)
+ sd->format = SND_PCM_FORMAT_U8;
+ else if (h->precision == 16)
+ sd->format = SND_PCM_FORMAT_S16_LE;
+ else
+ error ("Unsupported WAV file format");
+ }
+ else if (s->type == SUN_AUDIO)
+ {
+ struct au_header *header = (struct au_header *) s->header;
+ switch (header->encoding)
+ {
+ case AU_ENCODING_ULAW_8:
+ sd->format = SND_PCM_FORMAT_MU_LAW;
+ break;
+ case AU_ENCODING_ALAW_8:
+ sd->format = SND_PCM_FORMAT_A_LAW;
+ break;
+ case AU_ENCODING_IEEE32:
+ sd->format = SND_PCM_FORMAT_FLOAT_BE;
+ break;
+ case AU_ENCODING_IEEE64:
+ sd->format = SND_PCM_FORMAT_FLOAT64_BE;
+ break;
+ case AU_ENCODING_8:
+ sd->format = SND_PCM_FORMAT_S8;
+ break;
+ case AU_ENCODING_16:
+ sd->format = SND_PCM_FORMAT_S16_BE;
+ break;
+ case AU_ENCODING_24:
+ sd->format = SND_PCM_FORMAT_S24_BE;
+ break;
+ case AU_ENCODING_32:
+ sd->format = SND_PCM_FORMAT_S32_BE;
+ break;
+
+ default:
+ error ("Unsupported AU file format");
+ }
+ }
+ else
+ abort ();
+}
+
+
+/* Write NBYTES bytes from BUFFER to device SD. */
+
+static void
+alsa_write (sd, buffer, nbytes)
+ struct sound_device *sd;
+ const char *buffer;
+ int nbytes;
+{
+ struct alsa_params *p = (struct alsa_params *) sd->data;
+
+ /* The the third parameter to snd_pcm_writei is frames, not bytes. */
+ int fact = snd_pcm_format_size (sd->format, 1) * sd->channels;
+ int nwritten = 0;
+ int err;
+
+ while (nwritten < nbytes)
+ {
+ snd_pcm_uframes_t frames = (nbytes - nwritten)/fact;
+ if (frames == 0) break;
+
+ err = snd_pcm_writei (p->handle, buffer + nwritten, frames);
+ if (err < 0)
+ {
+ if (err == -EPIPE)
+ { /* under-run */
+ err = snd_pcm_prepare (p->handle);
+ if (err < 0)
+ alsa_sound_perror ("Can't recover from underrun, prepare failed",
+ err);
+ }
+ else if (err == -ESTRPIPE)
+ {
+ while ((err = snd_pcm_resume (p->handle)) == -EAGAIN)
+ sleep(1); /* wait until the suspend flag is released */
+ if (err < 0)
+ {
+ err = snd_pcm_prepare (p->handle);
+ if (err < 0)
+ alsa_sound_perror ("Can't recover from suspend, "
+ "prepare failed",
+ err);
+ }
+ }
+ else
+ alsa_sound_perror ("Error writing to sound device", err);
+
+ }
+ else
+ nwritten += err * fact;
+ }
+}
+
+static void
+snd_error_quiet (file, line, function, err, fmt)
+ const char *file;
+ int line;
+ const char *function;
+ int err;
+ const char *fmt;
+{
+}
+
+/* Initialize device SD. Set up the interface functions in the device
+ structure. */
+
+static int
+alsa_init (sd)
+ struct sound_device *sd;
+{
+ char *file;
+ snd_pcm_t *handle;
+ int err;
+
+ /* Open the sound device. Default is "default". */
+ if (sd->file)
+ file = sd->file;
+ else
+ file = DEFAULT_ALSA_SOUND_DEVICE;
+
+ snd_lib_error_set_handler ((snd_lib_error_handler_t) snd_error_quiet);
+ err = snd_pcm_open (&handle, file, SND_PCM_STREAM_PLAYBACK, 0);
+ snd_lib_error_set_handler (NULL);
+ if (err < 0)
+ return 0;
+ snd_pcm_close (handle);
+
+ sd->fd = -1;
+ sd->open = alsa_open;
+ sd->close = alsa_close;
+ sd->configure = alsa_configure;
+ sd->choose_format = alsa_choose_format;
+ sd->write = alsa_write;
+ sd->period_size = alsa_period_size;
+
+ return 1;
+}
+
+#endif /* HAVE_ALSA */
+
+