mirrors/alsa-lib
1
0
Fork 0
mirror of https://github.com/alsa-project/alsa-lib.git synced 2025-10-31 22:25:35 -04:00
Code Issues Projects Releases Packages Wiki Activity Actions 1

Better PCM mmap API. Fixed pcm_multi

Browse source
This commit is contained in:
Abramo Bagnara 2001-04-13 15:40:53 +00:00
parent c4f95f48c3
commit 6a3b962d06
16 changed files with 279 additions and 279 deletions
Download patch file Download diff file Expand all files Collapse all files

100
src/pcm/pcm.c
View file

@ -1098,23 +1098,6 @@ snd_pcm_sframes_t snd_pcm_avail_update(snd_pcm_t *pcm)
return pcm->fast_ops->avail_update(pcm->fast_op_arg);
}
/**
* \brief Advance PCM frame position in mmap buffer
* \param pcm PCM handle
* \param size movement size
* \return a positive number of actual movement size otherwise a negative
* error code
*
* On playback does all the actions needed to transport the frames across
* underlying layers.
*/
snd_pcm_sframes_t snd_pcm_mmap_forward(snd_pcm_t *pcm, snd_pcm_uframes_t size)
{
assert(size > 0);
assert(size <= snd_pcm_mmap_avail(pcm));
return pcm->fast_ops->mmap_forward(pcm->fast_op_arg, size);
}
/**
* \brief Silence an area
* \param dst_area area specification
@ -3932,64 +3915,57 @@ void snd_pcm_info_set_stream(snd_pcm_info_t *obj, snd_pcm_stream_t val)
obj->stream = snd_enum_to_int(val);
}
/**
* \brief Get channel areas for a given PCM when running
* \brief Application request to access a portion of mmap area
* \param pcm PCM handle
* \return pointer to channel areas (one for each channel)
* \param areas Returned mmap channel areas
* \param offset Returned mmap area offset
* \param size mmap area portion size (wanted on entry, contiguous
available on exit)
* \return 0 on success otherwise a negative error code
*/
const snd_pcm_channel_area_t *snd_pcm_mmap_running_areas(snd_pcm_t *pcm)
{
return pcm->running_areas;
}
/**
* \brief Get channel areas for a given PCM when stopped
* \param pcm PCM handle
* \return pointer to channel areas (one for each channel)
*/
const snd_pcm_channel_area_t *snd_pcm_mmap_stopped_areas(snd_pcm_t *pcm)
{
return pcm->stopped_areas;
}
/**
* \brief Get appropriate channel areas for a given PCM according to its state (running or stopped)
* \param pcm PCM handle
* \return pointer to channel areas (one for each channel)
*/
const snd_pcm_channel_area_t *snd_pcm_mmap_areas(snd_pcm_t *pcm)
int snd_pcm_mmap_begin(snd_pcm_t *pcm,
const snd_pcm_channel_area_t **areas,
snd_pcm_uframes_t *offset,
snd_pcm_uframes_t *frames)
{
snd_pcm_uframes_t cont;
snd_pcm_uframes_t avail;
snd_pcm_uframes_t f;
assert(pcm && areas && offset && frames);
if (pcm->stopped_areas &&
snd_pcm_state(pcm) != SND_PCM_STATE_RUNNING)
return pcm->stopped_areas;
return pcm->running_areas;
}
/**
* \brief Correct frames count according to contiguity consideration inside PCM ring buffer
* \param pcm PCM handle
* \param frames Frames to transfer
* \return Number of contiguous frames transferrable
*/
snd_pcm_uframes_t snd_pcm_mmap_xfer(snd_pcm_t *pcm, snd_pcm_uframes_t frames)
{
assert(pcm);
if (pcm->stream == SND_PCM_STREAM_PLAYBACK)
return snd_pcm_mmap_playback_xfer(pcm, frames);
*areas = pcm->stopped_areas;
else
return snd_pcm_mmap_capture_xfer(pcm, frames);
*areas = pcm->running_areas;
*offset = *pcm->appl_ptr % pcm->buffer_size;
avail = snd_pcm_mmap_avail(pcm);
f = *frames;
if (f > avail)
f = avail;
cont = pcm->buffer_size - *pcm->appl_ptr % pcm->buffer_size;
if (f > cont)
f = cont;
*frames = f;
return 0;
}
/**
* \brief Return application offset inside ring buffer
* \brief Application has completed the access to area requested with
#snd_pcm_mmap_begin
* \param pcm PCM handle
* \return Offset for frames transfer
* \return 0 on success otherwise a negative error code
*
* To call this with offset/frames values different from that returned
* by snd_pcm_mmap_begin has undefined effects and it has to be avoided.
*/
snd_pcm_uframes_t snd_pcm_mmap_offset(snd_pcm_t *pcm)
int snd_pcm_mmap_commit(snd_pcm_t *pcm, snd_pcm_uframes_t offset,
snd_pcm_uframes_t frames)
{
assert(pcm);
return *pcm->appl_ptr % pcm->buffer_size;
assert(pcm);
assert(offset == *pcm->appl_ptr % pcm->buffer_size);
assert(frames <= snd_pcm_mmap_avail(pcm));
return pcm->fast_ops->mmap_commit(pcm->fast_op_arg, offset, frames);
}
#ifndef DOC_HIDDEN