para_server: Don't link with stat.o.
[paraslash.git] / alsa_write.c
index e070399..cf0f335 100644 (file)
 /** always use 16 bit little endian */
 #define FORMAT SND_PCM_FORMAT_S16_LE
 
-/** data specific to the alsa writer */
+/** Data specific to the alsa writer. */
 struct private_alsa_write_data {
-       /** the alsa handle */
+       /** The alsa handle */
        snd_pcm_t *handle;
-       /** determined and set by alsa_open() */
-       size_t bytes_per_frame;
-       /** don't write anything until this time */
+       /** Determined and set by alsa_open(). */
+       int bytes_per_frame;
+       /** Don't write anything until this time. */
        struct timeval next_chunk;
-       /** the return value of snd_pcm_hw_params_get_buffer_time_max() */
+       /** The approximate maximum buffer duration in us. */
        unsigned buffer_time;
        /**
-        * the samplerate given by command line option or the decoder
-        * of the writer node group
+        * The samplerate given by command line option or the decoder
+        * of the writer node group.
         */
        unsigned samplerate;
        /**
@@ -101,7 +101,8 @@ static int alsa_init(struct private_alsa_write_data *pad,
        if (buffer_size < 1)
                start_threshold = 1;
        else
-               start_threshold = buffer_size;
+               start_threshold = PARA_MIN(buffer_size,
+                       (snd_pcm_uframes_t)pad->samplerate);
        if (snd_pcm_sw_params_set_start_threshold(pad->handle, swparams,
                        start_threshold) < 0)
                return -E_START_THRESHOLD;
@@ -113,7 +114,9 @@ static int alsa_init(struct private_alsa_write_data *pad,
                PARA_WARNING_LOG("unable to install sw params\n");
        pad->bytes_per_frame = snd_pcm_format_physical_width(FORMAT)
                * pad->channels / 8;
-       PARA_INFO_LOG("bytes per frame: %zu\n", pad->bytes_per_frame);
+       if (pad->bytes_per_frame <= 0)
+               return -E_PHYSICAL_WIDTH;
+       PARA_INFO_LOG("bytes per frame: %d\n", pad->bytes_per_frame);
        if (snd_pcm_nonblock(pad->handle, 1))
                PARA_ERROR_LOG("failed to set nonblock mode\n");
        return 1;
@@ -163,48 +166,49 @@ static int alsa_write_post_select(__a_unused struct sched *s,
 {
        struct private_alsa_write_data *pad = wn->private_data;
        struct writer_node_group *wng = wn->wng;
-       size_t frames, bytes = *wng->loaded - wn->written;
-       unsigned char *data = (unsigned char*)wng->buf + wn->written;
+       size_t bytes = *wng->loaded - wn->written;
+       unsigned char *data = (unsigned char*)*wng->bufp + wn->written;
        struct timeval tv;
-       snd_pcm_sframes_t ret;
+       snd_pcm_sframes_t ret, frames, avail;
 
+       if (*wng->input_error < 0 && (!pad->handle || bytes < pad->bytes_per_frame)) {
+               wn->written = *wng->loaded;
+               return *wng->input_error;
+       }
        if (!bytes) /* no data available */
-               goto out;
+               return 0;
        if (tv_diff(now, &pad->next_chunk, NULL) < 0)
-               goto out;
+               return 0;
        if (!pad->handle) {
                int err = alsa_init(pad, wn->conf);
                if (err < 0)
                        return err;
        }
        frames = bytes / pad->bytes_per_frame;
+       if (!frames) /* less than a single frame available */
+               return 0;
+       avail = snd_pcm_avail_update(pad->handle);
+       if (avail <= 0)
+               goto delay;
+       frames = PARA_MIN(frames, avail);
        ret = snd_pcm_writei(pad->handle, data, frames);
-       if (ret == -EPIPE) {
-               PARA_WARNING_LOG("EPIPE\n");
-               snd_pcm_prepare(pad->handle);
-               return 1;
-       }
-       if (ret < 0 && ret != -EAGAIN) {
-               PARA_WARNING_LOG("alsa error (%zu frames, ret = %d\n",
-                       frames, (int)ret);
+       if (ret < 0) {
+               PARA_WARNING_LOG("%s\n", snd_strerror(-ret));
+               if (ret == -EPIPE) {
+                       snd_pcm_prepare(pad->handle);
+                       return 0;
+               }
+               if (ret == -EAGAIN)
+                       goto delay;
                return -E_ALSA_WRITE;
        }
-       if (ret == -EAGAIN)
-               PARA_DEBUG_LOG("EAGAIN\n");
-       else
-               wn->written += ret * pad->bytes_per_frame;
-       if (ret == frames) /* we wrote everything, try again immediately */
-               pad->next_chunk = *now;
-       else {
-               ms2tv(pad->buffer_time / pad->bytes_per_frame / 1000, &tv);
-               tv_add(now, &tv, &pad->next_chunk);
-       }
-out:
-       if (*wng->input_error < 0) {
-               wn->written = *wng->loaded;
-               return *wng->input_error;
-       }
+       wn->written += ret * pad->bytes_per_frame;
        return 1;
+delay:
+       /* wait until 50% buffer space is available */
+       ms2tv(pad->buffer_time / 2000, &tv);
+       tv_add(now, &tv, &pad->next_chunk);
+       return 0;
 }
 
 static void alsa_close(struct writer_node *wn)