From d2985fff2beebb342a92ee01b102df7d8a8c653e Mon Sep 17 00:00:00 2001
From: Alexandre Ratchov <alex@caoua.org>
Date: Wed, 10 Jul 2019 16:04:38 +0200
Subject: [PATCH] Replace the "umap" bitmap by a simple table of slot pointers.

Makes the code simpler at virtually no cost since we need 8 entries
only. No behavior change.
---
 sndiod/dev.c | 41 +++++++++++++++++++----------------------
 1 file changed, 19 insertions(+), 22 deletions(-)

diff --git a/sndiod/dev.c b/sndiod/dev.c
index 02cac00..a24317c 100644
--- a/sndiod/dev.c
+++ b/sndiod/dev.c
@@ -1534,8 +1534,8 @@ slot_new(struct dev *d, struct opt *opt, char *who,
 {
 	char *p;
 	char name[SLOT_NAMEMAX];
-	unsigned int i, unit, umap = 0;
-	unsigned int ser, bestser, bestidx;
+	unsigned int i, ser, bestser, bestidx;
+	struct slot *unit[DEV_NSLOT];
 	struct slot *s;
 
 	/*
@@ -1554,30 +1554,26 @@ slot_new(struct dev *d, struct opt *opt, char *who,
 		strlcpy(name, "noname", SLOT_NAMEMAX);
 
 	/*
-	 * find the first unused "unit" number for this name
+	 * build a unit-to-slot map for this name
 	 */
-	for (i = 0, s = d->slot; i < DEV_NSLOT; i++, s++) {
-		if (s->ops == NULL)
-			continue;
+	for (i = 0; i < DEV_NSLOT; i++)
+		unit[i] = NULL;
+	for (i = 0; i < DEV_NSLOT; i++) {
+		s = d->slot + i;
 		if (strcmp(s->name, name) == 0)
-			umap |= (1 << s->unit);
-	}
-	for (unit = 0; ; unit++) {
-		if ((umap & (1 << unit)) == 0)
-			break;
+			unit[s->unit] = s;
 	}
 
 	/*
-	 * find a free controller slot with the same name/unit
+	 * find the free slot with the least unit number
 	 */
-	for (i = 0, s = d->slot; i < DEV_NSLOT; i++, s++) {
-		if (s->ops == NULL &&
-		    strcmp(s->name, name) == 0 &&
-		    s->unit == unit) {
+	for (i = 0; i < DEV_NSLOT; i++) {
+		s = unit[i];
+		if (s != NULL && s->ops == NULL) {
 #ifdef DEBUG
 			if (log_level >= 3) {
-				log_puts(name);
-				log_putu(unit);
+				log_puts(s->name);
+				log_putu(s->unit);
 				log_puts(": reused\n");
 			}
 #endif
@@ -1605,11 +1601,13 @@ slot_new(struct dev *d, struct opt *opt, char *who,
 		s->vol = MIDI_MAXCTL;
 		strlcpy(s->name, name, SLOT_NAMEMAX);
 		s->serial = d->serial++;
-		s->unit = unit;
+		for (i = 0; unit[i] != NULL; i++)
+			; /* nothing */
+		s->unit = i;
 #ifdef DEBUG
 		if (log_level >= 3) {
-			log_puts(name);
-			log_putu(unit);
+			log_puts(s->name);
+			log_putu(s->unit);
 			log_puts(": overwritten slot ");
 			log_putu(bestidx);
 			log_puts("\n");
@@ -1619,7 +1617,6 @@ slot_new(struct dev *d, struct opt *opt, char *who,
 	}
 	if (log_level >= 1) {
 		log_puts(name);
-		log_putu(unit);
 		log_puts(": out of sub-device slots\n");
 	}
 	return NULL;