Iwai-san,
On Jul 3 2018 22:59, twischer@xxxxxxxxxxxxxx wrote:
From: Timo Wischer <twischer@xxxxxxxxxxxxxx>
This function can be called without calling snd_pcm_avail_update().
The call to snd_pcm_avail_update() can take some time.
Therefore some developers would not like to call it from a real-time
context (e.g. from JACK client context).
Signed-off-by: Timo Wischer <twischer@xxxxxxxxxxxxxx>
diff --git a/include/pcm_ioplug.h b/include/pcm_ioplug.h
index c1310e3..b16fc8b 100644
--- a/include/pcm_ioplug.h
+++ b/include/pcm_ioplug.h
@@ -235,6 +235,9 @@ int snd_pcm_ioplug_set_param_list(snd_pcm_ioplug_t *io, int type, unsigned int n
int snd_pcm_ioplug_set_state(snd_pcm_ioplug_t *ioplug, snd_pcm_state_t state);
/* calucalte the available frames */
+snd_pcm_uframes_t snd_pcm_ioplug_avail(const snd_pcm_ioplug_t * const ioplug,
+ const snd_pcm_uframes_t hw_ptr,
+ const snd_pcm_uframes_t appl_ptr);
snd_pcm_uframes_t snd_pcm_ioplug_hw_avail(const snd_pcm_ioplug_t * const ioplug,
const snd_pcm_uframes_t hw_ptr,
const snd_pcm_uframes_t appl_ptr);
diff --git a/src/pcm/pcm_ioplug.c b/src/pcm/pcm_ioplug.c
index 4d44ae2..6d52c27 100644
--- a/src/pcm/pcm_ioplug.c
+++ b/src/pcm/pcm_ioplug.c
@@ -1221,6 +1221,21 @@ int snd_pcm_ioplug_set_state(snd_pcm_ioplug_t *ioplug, snd_pcm_state_t state)
* \param ioplug the ioplug handle
* \param hw_ptr hardware pointer in frames
* \param appl_ptr application pointer in frames
+ * \return available frames for the application
+ */
+snd_pcm_uframes_t snd_pcm_ioplug_avail(const snd_pcm_ioplug_t * const ioplug,
+ const snd_pcm_uframes_t hw_ptr,
+ const snd_pcm_uframes_t appl_ptr)
+{
+ return __snd_pcm_avail(ioplug->pcm, hw_ptr, appl_ptr);
+}
+
+/**
+ * \brief Get the available frames. This function can be used to calculate the
+ * the available frames before calling #snd_pcm_avail_update()
+ * \param ioplug the ioplug handle
+ * \param hw_ptr hardware pointer in frames
+ * \param appl_ptr application pointer in frames
* \return available frames for the hardware
*/
snd_pcm_uframes_t snd_pcm_ioplug_hw_avail(const snd_pcm_ioplug_t * const ioplug,
@@ -1230,8 +1245,9 @@ snd_pcm_uframes_t snd_pcm_ioplug_hw_avail(const snd_pcm_ioplug_t * const ioplug,
/* available data/space which can be transferred by the user
* application
*/
- const snd_pcm_uframes_t user_avail = __snd_pcm_avail(ioplug->pcm,
- hw_ptr, appl_ptr);
+ const snd_pcm_uframes_t user_avail = snd_pcm_ioplug_avail(ioplug,
+ hw_ptr,
+ appl_ptr);
if (user_avail > ioplug->pcm->buffer_size) {
/* there was an Xrun */
I have a question about maintenance policy of this library to update
version script for GNU Linker (ld) when introducing new symbols. The
version script is not updated since node name as 'ALSA_0.9.7'. The newly
intduced symbol, 'snd_pcm_ioplug_hw_avail' is in node name of
'ALSA_0.9'.
```
$ readelf -s src/.libs/libasound.so.2.0.0 | grep snd_pcm_ioplug_hw_avail
1254: 000000000009bfe0 40 FUNC GLOBAL DEFAULT 13
snd_pcm_ioplug_hw_avail@@ALSA_0.9
3840: 000000000009bfe0 40 FUNC GLOBAL DEFAULT 13
snd_pcm_ioplug_hw_avail
```
The last node name is 'ALSA_1.1.6':
```
$ tail -n 10 src/Versions.in
global:
@SYMBOL_PREFIX@alsa_lisp_*;
} ALSA_0.9.5;
ALSA_1.1.6 {
global:
@SYMBOL_PREFIX@snd_dlopen;
} ALSA_0.9.7;
```
Practically this brings no issue, but theoretically the newly introduced
symbol should be in a new node name next to ALSA_1.1.6. I'm not so
strict in this point, but it's better to decide maintenance policy
(because I've added some APIs in recent years).
Regards
Takashi Sakamoto
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