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Removed snd_pcm_mmap_begin_avail and changed snd_pcm_mmap_begin behaviour back.

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This commit is contained in:
Jaroslav Kysela 2001-12-10 17:16:13 +00:00
parent bcf50519e4
commit 5c98225fc0
3 changed files with 34 additions and 65 deletions
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5
include/pcm.h
View file

@ -790,11 +790,6 @@ 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);
int snd_pcm_mmap_begin_avail(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 avail);
int snd_pcm_mmap_commit(snd_pcm_t *pcm,
snd_pcm_uframes_t offset,
snd_pcm_uframes_t frames);

92
src/pcm/pcm.c
View file

@ -4830,6 +4830,9 @@ void snd_pcm_info_set_stream(snd_pcm_info_t *obj, snd_pcm_stream_t val)
* \param size mmap area portion size in frames (wanted on entry, contiguous available on exit)
* \return 0 on success otherwise a negative error code
*
* It is necessary to call the snd_pcm_avail_update() function directly before
* this call. Otherwise, this function can return a wrong count of available frames.
*
* The function should be called before a sample-direct area can be accessed.
* The resulting size parameter is always less or equal to the input count of frames
* and can be zero, if no frames can be processed (the ring buffer is full).
@ -4842,39 +4845,11 @@ 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_sframes_t avail;
avail = snd_pcm_avail_update(pcm);
if (avail < 0)
return avail;
return snd_pcm_mmap_begin_avail(pcm, areas, offset, frames, avail);
}
/**
* \brief Application request to access a portion of direct (mmap) area
* \param pcm PCM handle
* \param areas Returned mmap channel areas
* \param offset Returned mmap area offset in area steps (== frames)
* \param size mmap area portion size in frames (wanted on entry, contiguous available on exit)
* \param avail available frames (result from snd_pcm_avail_update())
* \return 0 on success otherwise a negative error code
*
* See snd_pcm_mmap_begin() function for more details. The only difference
* is in the optimization for applications using snd_pcm_avail_update()
* directly before snd_pcm_mmap_begin() call. In the case, this function
* should be used to avoid twice or more calls to time consuming
* snd_pcm_avail_update() function.
*/
int snd_pcm_mmap_begin_avail(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 avail)
{
snd_pcm_uframes_t cont;
snd_pcm_uframes_t f;
assert(pcm && areas && offset && frames && avail <= pcm->buffer_size);
snd_pcm_uframes_t avail;
assert(pcm && areas && offset && frames);
if (pcm->stopped_areas &&
snd_pcm_state(pcm) != SND_PCM_STATE_RUNNING)
*areas = pcm->stopped_areas;
@ -4883,6 +4858,9 @@ int snd_pcm_mmap_begin_avail(snd_pcm_t *pcm,
*offset = *pcm->appl_ptr % pcm->buffer_size;
cont = pcm->buffer_size - *offset;
f = *frames;
avail = snd_pcm_mmap_avail(pcm);
if (avail > pcm->buffer_size)
return -EPIPE;
if (f > avail)
f = avail;
if (f > cont)
@ -4901,46 +4879,42 @@ int snd_pcm_mmap_begin_avail(snd_pcm_t *pcm,
* You should pass this function the offset value that
* snd_pcm_mmap_begin() returned. The frames parameter should hold the
* number of frames you have written or read to/from the audio
* buffer. The frames parameter must never exceed the configuous frames
* buffer. The frames parameter must never exceed the contiguous frames
* count that snd_pcm_mmap_begin() returned. Each call to snd_pcm_mmap_begin()
* must be followed by a call to snd_pcm_mmap_commit().
*
* Example #1:
* Example:
\code
double phase = 0;
const snd_pcm_area_t *areas;
snd_pcm_uframes_t offset, frames;
frames = frame_buffer_size;
err = snd_pcm_mmap_begin(pcm_handle, &areas, &offset, &frames);
if (err < 0)
error(err);
// this function fills the areas from offset with count of frames
generate_sine(areas, offset, frames, &phase);
err = snd_pcm_mmap_commit(pcm_handle, offset, frames);
if (err < 0)
error(err);
\endcode
*
* Example #2 (determine available frame count at beginning):
\code
double phase = 0;
const snd_pcm_area_t *areas;
snd_pcm_sframes_t avail;
snd_pcm_sframes_t avail, size;
snd_pcm_uframes_t offset, frames;
avail = snd_pcm_avail_update(pcm);
if (avail < 0)
error(avail);
frames = frame_buffer_size > avail ? avail : frame_buffer_size;
err = snd_pcm_mmap_begin_avail(pcm_handle, &areas, &offset, &frames, avail);
if (err < 0)
error(err);
// this function fills the areas from offset with count of frames
generate_sine(areas, offset, frames, &phase);
err = snd_pcm_mmap_commit(pcm_handle, offset, frames);
if (err < 0)
error(err);
// at this point, we can transfer at least 'avail' frames
// we want to process frames in chunks (period_size)
if (avail < period_size)
goto _skip;
size = period_size;
// it is possible that contiguous areas are smaller, thus we use a loop
while (size > 0) {
frames = size;
err = snd_pcm_mmap_begin(pcm_handle, &areas, &offset, &frames);
if (err < 0)
error(err);
// this function fills the areas from offset with count of frames
generate_sine(areas, offset, frames, &phase);
err = snd_pcm_mmap_commit(pcm_handle, offset, frames);
if (err < 0)
error(err);
size -= frames;
}
_skip:
\endcode
*
* Look to the \ref example_test_pcm "Sine-wave generator" example

2
test/pcm.c
View file

@ -465,7 +465,7 @@ static int direct_loop(snd_pcm_t *handle,
size = period_size;
while (size > 0) {
frames = size;
err = snd_pcm_mmap_begin_avail(handle, &my_areas, &offset, &frames, avail);
err = snd_pcm_mmap_begin(handle, &my_areas, &offset, &frames);
if (err < 0) {
if ((err = xrun_recovery(handle, err)) < 0) {
printf("MMAP begin avail error: %s\n", snd_strerror(err));