lev comp: Simplify mon gen save/restore code

Also, the monster generation marker is now 8 bits instead of 32.

This goes with commit a6d9021 (unhardcode quest mon gen).

libnitrohack/src/restore.c

@@ -159,35 +159,31 @@ static void restdamage(struct memfile *mf, struct level *lev, boolean ghostly)
 
 static struct mon_gen_override *rest_mongen_override(struct memfile *mf)
 {
-	int marker;
 	struct mon_gen_override *or;
 	struct mon_gen_tuple *mt;
-	boolean has_gen_chances, next;
 
 	or = NULL;
 
 	mfmagic_check(mf, MONGEN_MAGIC);
 
-	marker = mread32(mf);
-	if (marker) {
+	/* Check for mon gen marker. */
+	if (mread8(mf)) {
 	    or = malloc(sizeof(*or));
 	    or->override_chance = mread32(mf);
 	    or->total_mon_freq = mread32(mf);
-	    has_gen_chances = mread8(mf) ? TRUE : FALSE;
 	    or->gen_chances = NULL;
 
-	    if (has_gen_chances) {
-		do {
-		    mfmagic_check(mf, MONGENTUPLE_MAGIC);
-		    mt = malloc(sizeof(*mt));
-		    mt->freq = mread32(mf);
-		    mt->is_sym = mread8(mf) ? TRUE : FALSE;
-		    mt->monid = mread32(mf);
-		    next = mread8(mf) ? TRUE : FALSE;
-
-		    mt->next = or->gen_chances;
-		    or->gen_chances = mt;
-		} while (next);
+	    /* Check for next tuple marker. */
+	    while (mread8(mf)) {
+		mfmagic_check(mf, MONGENTUPLE_MAGIC);
+
+		mt = malloc(sizeof(*mt));
+		mt->freq = mread32(mf);
+		mt->is_sym = mread8(mf) ? TRUE : FALSE;
+		mt->monid = mread32(mf);
+
+		mt->next = or->gen_chances;
+		or->gen_chances = mt;
 	    }
 	}
 

libnitrohack/src/save.c

@@ -449,25 +449,27 @@ static void save_mongen_override(struct memfile *mf, struct mon_gen_override *or
 	mfmagic_set(mf, MONGEN_MAGIC);
 
 	if (!or) {
-	    /* marker == 0 means no monster generation override */
-	    mwrite32(mf, 0);
+	    /* mon gen marker == 0: override doesn't exist */
+	    mwrite8(mf, 0);
 	} else {
-	    /* marker == 1 means monster generation override is present */
-	    mwrite32(mf, 1);
+	    /* mon gen marker == 1: override exists */
+	    mwrite8(mf, 1);
 	    mwrite32(mf, or->override_chance);
 	    mwrite32(mf, or->total_mon_freq);
-	    mwrite8(mf, or->gen_chances ? 1 : 0);
 
-	    mt = or->gen_chances;
-	    while (mt) {
+	    for (mt = or->gen_chances; mt; mt = mt->next) {
+		/* Write tuple marker. */
+		mwrite8(mf, 1);
+
 		mfmagic_set(mf, MONGENTUPLE_MAGIC);
+
 		mwrite32(mf, mt->freq);
 		mwrite8(mf, mt->is_sym ? 1 : 0);
 		mwrite32(mf, mt->monid);
-		mwrite8(mf, mt->next ? 1 : 0);
-
-		mt = mt->next;
 	    }
+
+	    /* End-of-tuples marker. */
+	    mwrite8(mf, 0);
 	}
 }