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Removed snd_pcm_hwptr().

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Added snd_pcm_hwdiff() and snd_pcm_forward().
Returned the behaviour for snd_pcm_mmap_begin().
This commit is contained in:
Jaroslav Kysela 2003-02-22 17:19:02 +00:00
parent fbd99fdec0
commit 2dab1dfbc3
17 changed files with 327 additions and 246 deletions
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73
src/pcm/pcm.c
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@ -400,6 +400,12 @@ only when the stream is in the running or draining (playback only) state.
Note that this function does not update the current r/w pointer for applications,
so the function \link ::snd_pcm_avail_update \endlink must be called afterwards
before any read/write begin+commit operations.
<p>
To determine the processed frames by hardware, the function \link ::snd_pcm_hwdiff \endlink
might be used. Note that this function returns cached value which is synchronized with
hardware using the \link ::snd_pcm_hwsync \endlink function. The application may
manage the right r/w pointer via \link ::snd_pcm_rewind \endlink and
\link ::snd_pcm_forward \endlink functions.
\section pcm_action Managing the stream state
@ -869,28 +875,42 @@ int snd_pcm_hwsync(snd_pcm_t *pcm)
}
/**
* \brief Return hardware pointer
* \brief Return count of processed frames by hardware from last call
* \param pcm PCM handle
* \param diff Difference between last position and current
* \param old_pos Old position on entry, actual position on exit
* \return 0 on success otherwise a negative error code
*
* The hardware pointer is in range 0 ... (boundary - 1). It contains
* The old_ptr parameter is in range 0 ... (boundary - 1). It contains
* count_of_ring_buffer_crosses * buffer_size + offset in the ring buffer.
* Using this value is not intented
*
* Note this function does not return the real hardware pointer.
* Note this function does not obtain the real position from hardware.
* The function \link ::snd_pcm_hwsync \endlink have to be called
* before to obtain the real hardware position.
*/
#ifndef DOXYGEN
int INTERNAL(snd_pcm_hwptr)(snd_pcm_t *pcm, snd_pcm_uframes_t *hwptr)
int INTERNAL(snd_pcm_hwdiff)(snd_pcm_t *pcm, snd_pcm_uframes_t *diff, snd_pcm_uframes_t *old_pos)
#else
int snd_pcm_hwptr(snd_pcm_t *pcm, snd_pcm_uframes_t *hwptr)
int snd_pcm_hwdiff(snd_pcm_t *pcm, snd_pcm_uframes_t *diff, snd_pcm_uframes_t *old_pos)
#endif
{
assert(pcm);
snd_pcm_uframes_t d, hw_ptr;
assert(pcm && diff && old_pos);
assert(pcm->setup);
return pcm->fast_ops->hwptr(pcm->fast_op_arg, hwptr);
assert(*old_pos < pcm->boundary);
hw_ptr = *pcm->hw.ptr;
if (hw_ptr < *old_pos) {
d = (pcm->boundary - *old_pos) + hw_ptr;
} else {
d = hw_ptr - *old_pos;
}
*diff = d;
*old_pos = hw_ptr;
return 0;
}
default_symbol_version(__snd_pcm_hwptr, snd_pcm_hwptr, ALSA_0.9.0rc8);
default_symbol_version(__snd_pcm_hwdiff, snd_pcm_hwdiff, ALSA_0.9.0rc8);
/**
* \brief Obtain delay for a running PCM handle
@ -1029,6 +1049,25 @@ snd_pcm_sframes_t snd_pcm_rewind(snd_pcm_t *pcm, snd_pcm_uframes_t frames)
return pcm->fast_ops->rewind(pcm->fast_op_arg, frames);
}
/**
* \brief Move application frame position forward
* \param pcm PCM handle
* \param frames wanted skip in frames
* \return a positive number for actual skip otherwise a negative error code
*/
#ifndef DOXYGEN
snd_pcm_sframes_t INTERNAL(snd_pcm_forward)(snd_pcm_t *pcm, snd_pcm_uframes_t frames)
#else
snd_pcm_sframes_t snd_pcm_forward(snd_pcm_t *pcm, snd_pcm_uframes_t frames)
#endif
{
assert(pcm);
assert(pcm->setup);
assert(frames > 0);
return pcm->fast_ops->forward(pcm->fast_op_arg, frames);
}
default_symbol_version(__snd_pcm_forward, snd_pcm_forward, ALSA_0.9.0rc8);
/**
* \brief Write interleaved frames to a PCM
* \param pcm PCM handle
@ -5816,7 +5855,7 @@ void snd_pcm_info_set_stream(snd_pcm_info_t *obj, snd_pcm_stream_t val)
* \brief Application request to access a portion of direct (mmap) area
* \param pcm PCM handle
* \param areas Returned mmap channel areas
* \param offset mmap area offset in area steps (== frames) (wanted on entry (see note), returned on exit)
* \param offset Returned mmap area offset in area steps (== frames)
* \param frames mmap area portion size in frames (wanted on entry, contiguous available on exit)
* \return 0 on success otherwise a negative error code
*
@ -5829,10 +5868,6 @@ void snd_pcm_info_set_stream(snd_pcm_info_t *obj, snd_pcm_stream_t val)
*
* See the snd_pcm_mmap_commit() function to finish the frame processing in
* the direct areas.
*
* Note: The offset value is always overriden when stop_threshold < boundary.
* Otherwise, the application must specify it's own offset value.
*
*/
int snd_pcm_mmap_begin(snd_pcm_t *pcm,
const snd_pcm_channel_area_t **areas,
@ -5844,16 +5879,10 @@ int snd_pcm_mmap_begin(snd_pcm_t *pcm,
snd_pcm_uframes_t avail;
assert(pcm && areas && offset && frames);
*areas = snd_pcm_mmap_areas(pcm);
if (pcm->stop_threshold < pcm->boundary) {
*offset = *pcm->appl.ptr % pcm->buffer_size;
avail = snd_pcm_mmap_avail(pcm);
if (avail > pcm->buffer_size)
avail = pcm->buffer_size;
} else {
if (*offset >= pcm->buffer_size)
return -EINVAL;
*offset = *pcm->appl.ptr % pcm->buffer_size;
avail = snd_pcm_mmap_avail(pcm);
if (avail > pcm->buffer_size)
avail = pcm->buffer_size;
}
cont = pcm->buffer_size - *offset;
f = *frames;
if (f > avail)