[alsa-devel] [PATCH RFC 01/21] ALSA: pcm: add a helper function to constrain mask-type parameters

[Takashi Sakamoto]

Application of constraints to mask-type parameters for PCM substream is
done in a call of snd_pcm_hw_refine(), while the function includes much
codes and is not enough friendly to readers.

This commit splits the codes to a separated function so that readers can
get it easily. I leave desicion into compilers to merge the function into
its callee.

Signed-off-by: Takashi Sakamoto <o-takashi at sakamocchi.jp>
---
 sound/core/pcm_native.c | 52 +++++++++++++++++++++++++++++++------------------
 1 file changed, 33 insertions(+), 19 deletions(-)

diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index 13dec5e..e5135e6 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -278,27 +278,12 @@ static const char * const snd_pcm_hw_param_names[] = {
 };
 #endif
 
-int snd_pcm_hw_refine(struct snd_pcm_substream *substream, 
-		      struct snd_pcm_hw_params *params)
+static int constrain_mask_params(struct snd_pcm_hw_constraints *constrs,
+				 struct snd_pcm_hw_params *params)
 {
+	struct snd_mask *m;
 	unsigned int k;
-	struct snd_pcm_hardware *hw;
-	struct snd_interval *i = NULL;
-	struct snd_mask *m = NULL;
-	struct snd_pcm_hw_constraints *constrs = &substream->runtime->hw_constraints;
-	unsigned int rstamps[constrs->rules_num];
-	unsigned int vstamps[SNDRV_PCM_HW_PARAM_LAST_INTERVAL + 1];
-	unsigned int stamp = 2;
-	int changed, again;
-
-	params->info = 0;
-	params->fifo_size = 0;
-	if (params->rmask & (1 << SNDRV_PCM_HW_PARAM_SAMPLE_BITS))
-		params->msbits = 0;
-	if (params->rmask & (1 << SNDRV_PCM_HW_PARAM_RATE)) {
-		params->rate_num = 0;
-		params->rate_den = 0;
-	}
+	int changed;
 
 	for (k = SNDRV_PCM_HW_PARAM_FIRST_MASK; k <= SNDRV_PCM_HW_PARAM_LAST_MASK; k++) {
 		m = hw_param_mask(params, k);
@@ -320,6 +305,35 @@ int snd_pcm_hw_refine(struct snd_pcm_substream *substream,
 			return changed;
 	}
 
+	return 0;
+}
+
+int snd_pcm_hw_refine(struct snd_pcm_substream *substream, 
+		      struct snd_pcm_hw_params *params)
+{
+	unsigned int k;
+	struct snd_pcm_hardware *hw;
+	struct snd_mask *m = NULL;
+	struct snd_interval *i = NULL;
+	struct snd_pcm_hw_constraints *constrs = &substream->runtime->hw_constraints;
+	unsigned int rstamps[constrs->rules_num];
+	unsigned int vstamps[SNDRV_PCM_HW_PARAM_LAST_INTERVAL + 1];
+	unsigned int stamp = 2;
+	int changed, again;
+
+	params->info = 0;
+	params->fifo_size = 0;
+	if (params->rmask & (1 << SNDRV_PCM_HW_PARAM_SAMPLE_BITS))
+		params->msbits = 0;
+	if (params->rmask & (1 << SNDRV_PCM_HW_PARAM_RATE)) {
+		params->rate_num = 0;
+		params->rate_den = 0;
+	}
+
+	changed = constrain_mask_params(constrs, params);
+	if (changed < 0)
+		return changed;
+
 	for (k = SNDRV_PCM_HW_PARAM_FIRST_INTERVAL; k <= SNDRV_PCM_HW_PARAM_LAST_INTERVAL; k++) {
 		i = hw_param_interval(params, k);
 		if (snd_interval_empty(i))
-- 
2.9.3