[alsa-devel] [PATCH 2/4] pcm: rate: add rewindable and forwardable callbacks

[Alexander E. Patrakov]

This commit does not fix nonsense values returned by the rewind and
forward callbacks. E.g., with period_size = 1024 and buffer_size = 4096,
an attempt to rewind 1024 samples from the nearly-full buffer returns
4090.

Due to these nonsense values, the current rate plugin should be treated
as non-rewindable. That's why the new callbacks return 0.

Signed-off-by: Alexander E. Patrakov <patrakov at gmail.com>
---
 src/pcm/pcm_rate.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/pcm/pcm_rate.c b/src/pcm/pcm_rate.c
index 2eb4b1b..58ed842 100644
--- a/src/pcm/pcm_rate.c
+++ b/src/pcm/pcm_rate.c
@@ -689,6 +689,16 @@ static int snd_pcm_rate_reset(snd_pcm_t *pcm)
 	return 0;
 }
 
+static snd_pcm_sframes_t snd_pcm_rate_rewindable(snd_pcm_t *pcm ATTRIBUTE_UNUSED)
+{
+	return 0;
+}
+
+static snd_pcm_sframes_t snd_pcm_rate_forwardable(snd_pcm_t *pcm ATTRIBUTE_UNUSED)
+{
+	return 0;
+}
+
 static snd_pcm_sframes_t snd_pcm_rate_rewind(snd_pcm_t *pcm, snd_pcm_uframes_t frames)
 {
 	snd_pcm_rate_t *rate = pcm->private_data;
@@ -1221,7 +1231,9 @@ static const snd_pcm_fast_ops_t snd_pcm_rate_fast_ops = {
 	.drop = snd_pcm_generic_drop,
 	.drain = snd_pcm_rate_drain,
 	.pause = snd_pcm_generic_pause,
+	.rewindable = snd_pcm_rate_rewindable,
 	.rewind = snd_pcm_rate_rewind,
+	.forwardable = snd_pcm_rate_forwardable,
 	.forward = snd_pcm_rate_forward,
 	.resume = snd_pcm_generic_resume,
 	.writei = snd_pcm_mmap_writei,
-- 
2.0.0