[alsa-devel] [PATCH RFC 06/21] ALSA: pcm: use goto statement instead of while statement to reduce indentation

[Takashi Sakamoto]

In a process to calculate parameters of PCM substream, application of all
rules is iterated several times till parameter dependencies are satisfied.
In current implementation, two loops are used for the design, however this
brings two-level indentation and decline readability.

This commit attempts to reduce the indentation by using goto statement,
instead of outer while loop.

Signed-off-by: Takashi Sakamoto <o-takashi at sakamocchi.jp>
---
 sound/core/pcm_native.c | 95 +++++++++++++++++++++++++------------------------
 1 file changed, 49 insertions(+), 46 deletions(-)

diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index 3fd2a63..4de9498 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -345,58 +345,61 @@ static int constrain_params_by_rules(struct snd_pcm_substream *substream,
 		rstamps[k] = 0;
 	for (k = 0; k <= SNDRV_PCM_HW_PARAM_LAST_INTERVAL; k++) 
 		vstamps[k] = (params->rmask & (1 << k)) ? 1 : 0;
-	do {
-		again = 0;
-		for (k = 0; k < constrs->rules_num; k++) {
-			struct snd_pcm_hw_rule *r = &constrs->rules[k];
-			unsigned int d;
-			int doit = 0;
-			if (r->cond && !(r->cond & params->flags))
-				continue;
-			for (d = 0; r->deps[d] >= 0; d++) {
-				if (vstamps[r->deps[d]] > rstamps[k]) {
-					doit = 1;
-					break;
-				}
-			}
-			if (!doit)
-				continue;
 
-			/* Keep old parameter to trace. */
-			if (trace_hw_params_mask_enabled()) {
-				if (hw_is_mask(r->var))
-					old_mask = *hw_param_mask(params, r->var);
-			}
-			if (trace_hw_params_interval_enabled()) {
-				if (hw_is_interval(r->var))
-					old_interval = *hw_param_interval(params, r->var);
+retry:
+	again = 0;
+	for (k = 0; k < constrs->rules_num; k++) {
+		struct snd_pcm_hw_rule *r = &constrs->rules[k];
+		unsigned int d;
+		int doit = 0;
+		if (r->cond && !(r->cond & params->flags))
+			continue;
+		for (d = 0; r->deps[d] >= 0; d++) {
+			if (vstamps[r->deps[d]] > rstamps[k]) {
+				doit = 1;
+				break;
 			}
+		}
+		if (!doit)
+			continue;
 
-			changed = r->func(params, r);
+		/* Keep old parameter to trace. */
+		if (trace_hw_params_mask_enabled()) {
+			if (hw_is_mask(r->var))
+				old_mask = *hw_param_mask(params, r->var);
+		}
+		if (trace_hw_params_interval_enabled()) {
+			if (hw_is_interval(r->var))
+				old_interval = *hw_param_interval(params, r->var);
+		}
 
-			/* Trace the parameter. */
-			if (hw_is_mask(r->var)) {
-				trace_hw_params_mask(substream, r->var, k,
-						&old_mask,
-						hw_param_mask(params, r->var));
-			}
-			if (hw_is_interval(r->var)) {
-				trace_hw_params_interval(substream, r->var, k,
-						&old_interval,
-						hw_param_interval(params, r->var));
-			}
+		changed = r->func(params, r);
 
-			rstamps[k] = stamp;
-			if (changed && r->var >= 0) {
-				params->cmask |= (1 << r->var);
-				vstamps[r->var] = stamp;
-				again = 1;
-			}
-			if (changed < 0)
-				return changed;
-			stamp++;
+		/* Trace the parameter. */
+		if (hw_is_mask(r->var)) {
+			trace_hw_params_mask(substream, r->var, k,
+					     &old_mask,
+					     hw_param_mask(params, r->var));
+		}
+		if (hw_is_interval(r->var)) {
+			trace_hw_params_interval(substream, r->var, k,
+						 &old_interval,
+						 hw_param_interval(params, r->var));
 		}
-	} while (again);
+
+		rstamps[k] = stamp;
+		if (changed && r->var >= 0) {
+			params->cmask |= (1 << r->var);
+			vstamps[r->var] = stamp;
+			again = 1;
+		}
+		if (changed < 0)
+			return changed;
+		stamp++;
+	}
+
+	if (again)
+		goto retry;
 
 	return 0;
 }
-- 
2.9.3