pcm: rate - rewrite the may_wait_for_avail_min callback for the rate plugin

Shuffle the code to avoid special conditions using the plugin type
in the generic plugin code. The rate plugin has the own
may_wait_for_avail_min callback implementation now.

Fixes: d21e0e01 ("pcm: plugin - fix avail_min calculation on rate plugin")
Fixes: https://github.com/alsa-project/alsa-lib/pull/218
Signed-off-by: Jaroslav Kysela <perex@perex.cz>

src/pcm/pcm_local.h

@@ -286,8 +286,6 @@ struct _snd_pcm {
 	snd1_pcm_wait_nocheck
 #define snd_pcm_rate_get_default_converter \
 	snd1_pcm_rate_get_default_converter
-#define snd_pcm_rate_slave_frames \
-	snd1_pcm_rate_slave_frames
 #define snd_pcm_set_hw_ptr \
 	snd1_pcm_set_hw_ptr
 #define snd_pcm_set_appl_ptr \
@@ -1011,8 +1009,6 @@ int snd_pcm_wait_nocheck(snd_pcm_t *pcm, int timeout);
 
 const snd_config_t *snd_pcm_rate_get_default_converter(snd_config_t *root);
 
-snd_pcm_uframes_t snd_pcm_rate_slave_frames(snd_pcm_t *pcm, snd_pcm_uframes_t frames);
-
 #define SND_PCM_HW_PARBIT_ACCESS	(1U << SND_PCM_HW_PARAM_ACCESS)
 #define SND_PCM_HW_PARBIT_FORMAT	(1U << SND_PCM_HW_PARAM_FORMAT)
 #define SND_PCM_HW_PARBIT_SUBFORMAT	(1U << SND_PCM_HW_PARAM_SUBFORMAT)

src/pcm/pcm_plugin.c

@@ -574,8 +574,10 @@ static int snd_pcm_plugin_status(snd_pcm_t *pcm, snd_pcm_status_t * status)
 	return 0;
 }
 
-int snd_pcm_plugin_may_wait_for_avail_min(snd_pcm_t *pcm,
+int snd_pcm_plugin_may_wait_for_avail_min_conv(
-					  snd_pcm_uframes_t avail)
+				snd_pcm_t *pcm,
+				snd_pcm_uframes_t avail,
+				snd_pcm_uframes_t (*conv)(snd_pcm_t *, snd_pcm_uframes_t))
 {
 	if (pcm->stream == SND_PCM_STREAM_CAPTURE &&
 	    pcm->access != SND_PCM_ACCESS_RW_INTERLEAVED &&
@@ -619,8 +621,8 @@ int snd_pcm_plugin_may_wait_for_avail_min(snd_pcm_t *pcm,
 		 * Can happen only on built-in rate plugin.
 		 * This code is also used by extplug, but extplug does not allow to alter the sampling rate.
 		 */
-		if (snd_pcm_type(pcm) == SND_PCM_TYPE_RATE)
+		if (conv)
-			needed_slave_avail_min = snd_pcm_rate_slave_frames(pcm, needed_slave_avail_min);
+			needed_slave_avail_min = conv(pcm, needed_slave_avail_min);
 
 		if (slave->avail_min != needed_slave_avail_min) {
 			snd_pcm_sw_params_t *swparams;
@@ -644,6 +646,12 @@ int snd_pcm_plugin_may_wait_for_avail_min(snd_pcm_t *pcm,
 	return snd_pcm_generic_may_wait_for_avail_min(pcm, avail);
 }
 
+int snd_pcm_plugin_may_wait_for_avail_min(snd_pcm_t *pcm,
+					  snd_pcm_uframes_t avail)
+{
+	return snd_pcm_plugin_may_wait_for_avail_min_conv(pcm, avail, NULL);
+}
+
 const snd_pcm_fast_ops_t snd_pcm_plugin_fast_ops = {
 	.status = snd_pcm_plugin_status,
 	.state = snd_pcm_generic_state,

src/pcm/pcm_plugin.h

@@ -50,6 +50,8 @@ typedef struct {
 /* make local functions really local */
 #define snd_pcm_plugin_init \
 	snd1_pcm_plugin_init
+#define snd_pcm_plugin_may_wait_for_avail_min_conv \
+	snd1_pcm_plugin_may_wait_for_avail_min_conv
 #define snd_pcm_plugin_may_wait_for_avail_min \
 	snd1_pcm_plugin_may_wait_for_avail_min
 #define snd_pcm_plugin_fast_ops \
@@ -66,6 +68,8 @@ typedef struct {
 void snd_pcm_plugin_init(snd_pcm_plugin_t *plugin);
 snd_pcm_sframes_t snd_pcm_plugin_rewind(snd_pcm_t *pcm, snd_pcm_uframes_t frames);
 snd_pcm_sframes_t snd_pcm_plugin_forward(snd_pcm_t *pcm, snd_pcm_uframes_t frames);
+int snd_pcm_plugin_may_wait_for_avail_min_conv(snd_pcm_t *pcm, snd_pcm_uframes_t avail,
+					       snd_pcm_uframes_t (*conv)(snd_pcm_t *, snd_pcm_uframes_t));
 int snd_pcm_plugin_may_wait_for_avail_min(snd_pcm_t *pcm, snd_pcm_uframes_t avail);
 
 extern const snd_pcm_fast_ops_t snd_pcm_plugin_fast_ops;

src/pcm/pcm_rate.c

@@ -1282,6 +1282,32 @@ static int snd_pcm_rate_close(snd_pcm_t *pcm)
 	return snd_pcm_generic_close(pcm);
 }
 
+/**
+ * \brief Convert rate pcm frames to corresponding rate slave pcm frames
+ * \param pcm PCM handle
+ * \param frames Frames to be converted to slave frames
+ * \retval Corresponding slave frames
+*/
+static snd_pcm_uframes_t snd_pcm_rate_slave_frames(snd_pcm_t *pcm, snd_pcm_uframes_t frames)
+{
+	snd_pcm_uframes_t sframes;
+	snd_pcm_rate_t *rate = pcm->private_data;
+
+	if (pcm->stream == SND_PCM_STREAM_PLAYBACK)
+		sframes = rate->ops.output_frames(rate->obj, frames);
+	else
+		sframes = rate->ops.input_frames(rate->obj, frames);
+
+	return sframes;
+}
+
+static int snd_pcm_rate_may_wait_for_avail_min(snd_pcm_t *pcm,
+					       snd_pcm_uframes_t avail)
+{
+	return snd_pcm_plugin_may_wait_for_avail_min_conv(pcm, avail,
+							  snd_pcm_rate_slave_frames);
+}
+
 static const snd_pcm_fast_ops_t snd_pcm_rate_fast_ops = {
 	.status = snd_pcm_rate_status,
 	.state = snd_pcm_rate_state,
@@ -1308,7 +1334,7 @@ static const snd_pcm_fast_ops_t snd_pcm_rate_fast_ops = {
 	.poll_descriptors_count = snd_pcm_generic_poll_descriptors_count,
 	.poll_descriptors = snd_pcm_generic_poll_descriptors,
 	.poll_revents = snd_pcm_rate_poll_revents,
-	.may_wait_for_avail_min = snd_pcm_plugin_may_wait_for_avail_min,
+	.may_wait_for_avail_min = snd_pcm_rate_may_wait_for_avail_min,
 };
 
 static const snd_pcm_ops_t snd_pcm_rate_ops = {
@@ -1343,25 +1369,6 @@ const snd_config_t *snd_pcm_rate_get_default_converter(snd_config_t *root)
 	return NULL;
 }
 
-/**
- * \brief Convert rate pcm frames to corresponding rate slave pcm frames
- * \param pcm PCM handle
- * \param frames Frames to be converted to slave frames
- * \retval Corresponding slave frames
-*/
-snd_pcm_uframes_t snd_pcm_rate_slave_frames(snd_pcm_t *pcm, snd_pcm_uframes_t frames)
-{
-	snd_pcm_uframes_t sframes;
-	snd_pcm_rate_t *rate = pcm->private_data;
-
-	if (pcm->stream == SND_PCM_STREAM_PLAYBACK)
-		sframes = rate->ops.output_frames(rate->obj, frames);
-	else
-		sframes = rate->ops.input_frames(rate->obj, frames);
-
-	return sframes;
-}
-
 static void rate_initial_setup(snd_pcm_rate_t *rate)
 {
 	if (rate->plugin_version == SND_PCM_RATE_PLUGIN_VERSION)