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pcm: plugin - tidy snd_pcm_plugin_avail_update()

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No functional changes - move the code to snd_pcm_plugin_sync_hw_ptr()
and put the mmap capture updates to separate function for readability.

Signed-off-by: Jaroslav Kysela <perex@perex.cz>
This commit is contained in:
Jaroslav Kysela 2021-01-03 16:34:04 +01:00
parent 49eea5d7bc
commit fa1895aa2b
1 changed files with 79 additions and 69 deletions
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148
src/pcm/pcm_plugin.c
View file

@ -460,82 +460,92 @@ snd_pcm_plugin_mmap_commit(snd_pcm_t *pcm,
return xfer > 0 ? xfer : err; return xfer > 0 ? xfer : err;
} }
static snd_pcm_sframes_t
snd_pcm_plugin_sync_hw_ptr_capture(snd_pcm_t *pcm,
snd_pcm_sframes_t slave_size)
{
snd_pcm_plugin_t *plugin = pcm->private_data;
snd_pcm_t *slave = plugin->gen.slave;
const snd_pcm_channel_area_t *areas;
snd_pcm_uframes_t xfer, hw_offset, size;
int err;
xfer = snd_pcm_mmap_capture_avail(pcm);
size = pcm->buffer_size - xfer;
areas = snd_pcm_mmap_areas(pcm);
hw_offset = snd_pcm_mmap_hw_offset(pcm);
while (size > 0 && slave_size > 0) {
snd_pcm_uframes_t frames = size;
snd_pcm_uframes_t cont = pcm->buffer_size - hw_offset;
const snd_pcm_channel_area_t *slave_areas;
snd_pcm_uframes_t slave_offset;
snd_pcm_uframes_t slave_frames = ULONG_MAX;
snd_pcm_sframes_t result;
/* As mentioned in the ALSA API (see pcm/pcm.c:942):
* The function #snd_pcm_avail_update()
* have to be called before any mmap begin+commit operation.
* Otherwise the snd_pcm_areas_copy will not called a second time.
* But this is needed, if the ring buffer wrap is reached and
* there is more data available.
*/
slave_size = snd_pcm_avail_update(slave);
result = snd_pcm_mmap_begin(slave, &slave_areas, &slave_offset, &slave_frames);
if (result < 0) {
err = result;
goto error;
}
if (frames > cont)
frames = cont;
frames = (plugin->read)(pcm, areas, hw_offset, frames,
slave_areas, slave_offset, &slave_frames);
result = snd_pcm_mmap_commit(slave, slave_offset, slave_frames);
if (result > 0 && (snd_pcm_uframes_t)result != slave_frames) {
snd_pcm_sframes_t res;
res = plugin->undo_read(slave, areas, hw_offset, frames, slave_frames - result);
if (res < 0) {
err = res;
goto error;
}
frames -= res;
}
if (result <= 0) {
err = result;
goto error;
}
snd_pcm_mmap_hw_forward(pcm, frames);
if (frames == cont)
hw_offset = 0;
else
hw_offset += frames;
size -= frames;
slave_size -= slave_frames;
xfer += frames;
}
return (snd_pcm_sframes_t)xfer;
error:
return xfer > 0 ? (snd_pcm_sframes_t)xfer : err;
}
static snd_pcm_sframes_t snd_pcm_plugin_sync_hw_ptr(snd_pcm_t *pcm,
snd_pcm_uframes_t slave_hw_ptr,
snd_pcm_sframes_t slave_size)
{
if (pcm->stream == SND_PCM_STREAM_CAPTURE &&
pcm->access != SND_PCM_ACCESS_RW_INTERLEAVED &&
pcm->access != SND_PCM_ACCESS_RW_NONINTERLEAVED)
return snd_pcm_plugin_sync_hw_ptr_capture(pcm, slave_size);
*pcm->hw.ptr = slave_hw_ptr;
return slave_size;
}
static snd_pcm_sframes_t snd_pcm_plugin_avail_update(snd_pcm_t *pcm) static snd_pcm_sframes_t snd_pcm_plugin_avail_update(snd_pcm_t *pcm)
{ {
snd_pcm_plugin_t *plugin = pcm->private_data; snd_pcm_plugin_t *plugin = pcm->private_data;
snd_pcm_t *slave = plugin->gen.slave; snd_pcm_t *slave = plugin->gen.slave;
snd_pcm_sframes_t slave_size; snd_pcm_sframes_t slave_size;
int err;
slave_size = snd_pcm_avail_update(slave); slave_size = snd_pcm_avail_update(slave);
if (pcm->stream == SND_PCM_STREAM_CAPTURE && return snd_pcm_plugin_sync_hw_ptr(pcm, *slave->hw.ptr, slave_size);
pcm->access != SND_PCM_ACCESS_RW_INTERLEAVED &&
pcm->access != SND_PCM_ACCESS_RW_NONINTERLEAVED)
goto _capture;
*pcm->hw.ptr = *slave->hw.ptr;
return slave_size;
_capture:
{
const snd_pcm_channel_area_t *areas;
snd_pcm_uframes_t xfer, hw_offset, size;
xfer = snd_pcm_mmap_capture_avail(pcm);
size = pcm->buffer_size - xfer;
areas = snd_pcm_mmap_areas(pcm);
hw_offset = snd_pcm_mmap_hw_offset(pcm);
while (size > 0 && slave_size > 0) {
snd_pcm_uframes_t frames = size;
snd_pcm_uframes_t cont = pcm->buffer_size - hw_offset;
const snd_pcm_channel_area_t *slave_areas;
snd_pcm_uframes_t slave_offset;
snd_pcm_uframes_t slave_frames = ULONG_MAX;
snd_pcm_sframes_t result;
/* As mentioned in the ALSA API (see pcm/pcm.c:942):
* The function #snd_pcm_avail_update()
* have to be called before any mmap begin+commit operation.
* Otherwise the snd_pcm_areas_copy will not called a second time.
* But this is needed, if the ring buffer wrap is reached and
* there is more data available.
*/
slave_size = snd_pcm_avail_update(slave);
result = snd_pcm_mmap_begin(slave, &slave_areas, &slave_offset, &slave_frames);
if (result < 0) {
err = result;
goto error;
}
if (frames > cont)
frames = cont;
frames = (plugin->read)(pcm, areas, hw_offset, frames,
slave_areas, slave_offset, &slave_frames);
result = snd_pcm_mmap_commit(slave, slave_offset, slave_frames);
if (result > 0 && (snd_pcm_uframes_t)result != slave_frames) {
snd_pcm_sframes_t res;
res = plugin->undo_read(slave, areas, hw_offset, frames, slave_frames - result);
if (res < 0) {
err = res;
goto error;
}
frames -= res;
}
if (result <= 0) {
err = result;
goto error;
}
snd_pcm_mmap_hw_forward(pcm, frames);
if (frames == cont)
hw_offset = 0;
else
hw_offset += frames;
size -= frames;
slave_size -= slave_frames;
xfer += frames;
}
return (snd_pcm_sframes_t)xfer;
error:
return xfer > 0 ? (snd_pcm_sframes_t)xfer : err;
}
} }
static int snd_pcm_plugin_status(snd_pcm_t *pcm, snd_pcm_status_t * status) static int snd_pcm_plugin_status(snd_pcm_t *pcm, snd_pcm_status_t * status)