para_play: introduce struct private_alsa_data

this structure combines all alsa specific state variables of
para_play. Its usage separates alsa specific stuff from the
generic code of para_play.

diff --git a/play.c b/play.c
index 38203b401c710f4629285ad81b74c67d4eb9c8f0..c8a80cf198224e0bc80b84e5c4f3c33c2f9324f5 100644 (file)
--- a/play.c
+++ b/play.c
@@ -33,9 +33,12 @@
 
 #define FORMAT SND_PCM_FORMAT_S16_LE
 
-static snd_pcm_t *handle;
+struct private_alsa_data {
+       snd_pcm_t *handle;
+       size_t bytes_per_frame;
+};
+
 static unsigned char *audiobuf;
-static size_t bytes_per_frame;
 static struct timeval *start_time;
 static struct gengetopt_args_info conf;
 
@@ -74,7 +77,7 @@ static int read_wav_header(void)
  *
  * Install PCM software and hardware configuration. Exit on errors.
  */
-static int alsa_init(void)
+static int alsa_init(void **private_data)
 {
        snd_pcm_hw_params_t *hwparams;
        snd_pcm_sw_params_t *swparams;
@@ -85,68 +88,72 @@ static int alsa_init(void)
        snd_pcm_info_t *info;
        snd_output_t *log;
        snd_pcm_uframes_t period_size;
+       struct private_alsa_data *pad = para_malloc(sizeof(struct private_alsa_data));
+       *private_data = pad;
 
        snd_pcm_info_alloca(&info);
        if (snd_output_stdio_attach(&log, stderr, 0) < 0)
                return -E_ALSA_LOG;
-       err = snd_pcm_open(&handle, conf.device_arg,
+       err = snd_pcm_open(&pad->handle, conf.device_arg,
                SND_PCM_STREAM_PLAYBACK, 0);
        if (err < 0)
                return -E_PCM_OPEN;
-       if ((err = snd_pcm_info(handle, info)) < 0)
+       if ((err = snd_pcm_info(pad->handle, info)) < 0)
                return -E_SND_PCM_INFO;
 
        snd_pcm_hw_params_alloca(&hwparams);
        snd_pcm_sw_params_alloca(&swparams);
-       if (snd_pcm_hw_params_any(handle, hwparams) < 0)
+       if (snd_pcm_hw_params_any(pad->handle, hwparams) < 0)
                return -E_BROKEN_CONF;
-       if (snd_pcm_hw_params_set_access(handle, hwparams,
+       if (snd_pcm_hw_params_set_access(pad->handle, hwparams,
                        SND_PCM_ACCESS_RW_INTERLEAVED) < 0)
                return -E_ACCESS_TYPE;
-       if (snd_pcm_hw_params_set_format(handle, hwparams, FORMAT) < 0)
+       if (snd_pcm_hw_params_set_format(pad->handle, hwparams, FORMAT) < 0)
                return -E_SAMPLE_FORMAT;
-       if (snd_pcm_hw_params_set_channels(handle, hwparams, conf.channels_arg) < 0)
+       if (snd_pcm_hw_params_set_channels(pad->handle, hwparams,
+                       conf.channels_arg) < 0)
                return -E_CHANNEL_COUNT;
-       if (snd_pcm_hw_params_set_rate_near(handle, hwparams,
+       if (snd_pcm_hw_params_set_rate_near(pad->handle, hwparams,
                        (unsigned int*) &conf.sample_rate_arg, 0) < 0)
                return -E_SET_RATE;
        err = snd_pcm_hw_params_get_buffer_time_max(hwparams, &buffer_time, 0);
        if (err < 0 || !buffer_time)
                return -E_GET_BUFFER_TIME;
        PARA_DEBUG_LOG("buffer time: %d\n", buffer_time);
-       if (snd_pcm_hw_params_set_buffer_time_near(handle, hwparams,
+       if (snd_pcm_hw_params_set_buffer_time_near(pad->handle, hwparams,
                        &buffer_time, 0) < 0)
                return -E_SET_BUFFER_TIME;
-       if (snd_pcm_hw_params(handle, hwparams) < 0)
+       if (snd_pcm_hw_params(pad->handle, hwparams) < 0)
                return -E_HW_PARAMS;
        snd_pcm_hw_params_get_period_size(hwparams, &period_size, 0);
        snd_pcm_hw_params_get_buffer_size(hwparams, &buffer_size);
        PARA_DEBUG_LOG("buffer size: %lu, period_size: %lu\n", buffer_size, period_size);
        if (period_size == buffer_size)
                return -E_BAD_PERIOD;
-       snd_pcm_sw_params_current(handle, swparams);
+       snd_pcm_sw_params_current(pad->handle, swparams);
        err = snd_pcm_sw_params_get_xfer_align(swparams, &xfer_align);
        if (err < 0 || !xfer_align)
                return -E_GET_XFER;
-//     snd_pcm_sw_params_set_sleep_min(handle, swparams, 0);
-       snd_pcm_sw_params_set_avail_min(handle, swparams, period_size);
+       snd_pcm_sw_params_set_avail_min(pad->handle, swparams, period_size);
        /* round to closest transfer boundary */
        start_threshold = (buffer_size / xfer_align) * xfer_align;
        if (start_threshold < 1)
                start_threshold = 1;
-       if (snd_pcm_sw_params_set_start_threshold(handle, swparams,
+       if (snd_pcm_sw_params_set_start_threshold(pad->handle, swparams,
                        start_threshold) < 0)
                return -E_START_THRESHOLD;
        stop_threshold = buffer_size;
-       if (snd_pcm_sw_params_set_stop_threshold(handle, swparams,
+       if (snd_pcm_sw_params_set_stop_threshold(pad->handle, swparams,
                        stop_threshold) < 0)
                return -E_STOP_THRESHOLD;
-       if (snd_pcm_sw_params_set_xfer_align(handle, swparams, xfer_align) < 0)
+       if (snd_pcm_sw_params_set_xfer_align(pad->handle, swparams,
+                       xfer_align) < 0)
                return -E_SET_XFER;
-       if (snd_pcm_sw_params(handle, swparams) < 0)
+       if (snd_pcm_sw_params(pad->handle, swparams) < 0)
                return -E_SW_PARAMS;
-       bytes_per_frame = snd_pcm_format_physical_width(FORMAT) * conf.channels_arg / 8;
-       return period_size * bytes_per_frame;
+       pad->bytes_per_frame = snd_pcm_format_physical_width(FORMAT)
+               * conf.channels_arg / 8;
+       return period_size * pad->bytes_per_frame;
 }
 
 /**
@@ -156,34 +163,37 @@ static int alsa_init(void)
  *
  * \return Number of bytes written, -E_ALSA_WRITE on errors.
  */
-static int alsa_write(u_char *data, size_t nbytes)
+static int alsa_write(u_char *data, size_t nbytes, void *private_data)
 {
-       size_t frames = nbytes / bytes_per_frame;
+       struct private_alsa_data *pad = private_data;
+       size_t frames = nbytes / pad->bytes_per_frame;
        snd_pcm_sframes_t r, result = 0;
+
        while (frames > 0) {
                /* write interleaved frames */
-               r = snd_pcm_writei(handle, data, frames);
+               r = snd_pcm_writei(pad->handle, data, frames);
                if (r < 0)
                        PARA_ERROR_LOG("write error: %s\n", snd_strerror(r));
                if (r == -EAGAIN || (r >= 0 && r < frames))
-                       snd_pcm_wait(handle, 1);
+                       snd_pcm_wait(pad->handle, 1);
                else if (r == -EPIPE)
-                       snd_pcm_prepare(handle);
+                       snd_pcm_prepare(pad->handle);
                else if (r < 0)
                        return -E_ALSA_WRITE;
                if (r > 0) {
                        result += r;
                        frames -= r;
-                       data += r * bytes_per_frame;
+                       data += r * pad->bytes_per_frame;
                }
        }
-       return result * bytes_per_frame;
+       return result * pad->bytes_per_frame;
 }
 
-static void alsa_shutdown(void)
+static void alsa_shutdown(void *private_data)
 {
-       snd_pcm_drain(handle);
-       snd_pcm_close(handle);
+       struct private_alsa_data *pad = private_data;
+       snd_pcm_drain(pad->handle);
+       snd_pcm_close(pad->handle);
        snd_config_update_free_global();
 }
 
@@ -237,7 +247,8 @@ static int play_pcm(size_t loaded)
        size_t bufsize, written = 0, prebuf_size;
        unsigned char *p;
        struct timeval delay;
-       int chunk_bytes, ret = alsa_init();
+       void *private_data;
+       int chunk_bytes, ret = alsa_init(&private_data);
 
        if (ret < 0)
                goto out;
@@ -256,7 +267,7 @@ again:
        }
        p = audiobuf;
        while (loaded >= chunk_bytes) {
-               ret = alsa_write(p, chunk_bytes);
+               ret = alsa_write(p, chunk_bytes, private_data);
                if (ret < 0)
                        goto out;
                p += ret;
@@ -277,7 +288,7 @@ read:
        }
        ret = 1;
 out:
-       alsa_shutdown();
+       alsa_shutdown(private_data);
        return ret;
 }