Shuffle external mode: Skip dupe char search if unique so far

run/john.conf

@@ -3971,7 +3971,7 @@ void next()
 
 # Shuffle (try all permutations of) characters in each short input word
 [List.External:Shuffle]
-int max_length, length, base[0x80], id[0x80], jd[0x80], unseen[0x80], unique[0x100], clz[0x1000];
+int max_length, length, base[0x80], id[0x80], jd[0x80], unseen[0x80], unique[0x100], c2mask[0x100], clz[0x1000];
 
 void init()
 {
@@ -3990,19 +3990,15 @@ void new()
 {
 	int c, i;
 
-	length = -1;
+	length = i = -1;
 	while (c = word[++length]) {
 		if (length > max_length)
 			return;
-		base[length] = c;
-		id[length] = 0;
-		i = unique[c] = -1;
-		while (++i < length) {
-			if (word[i] == c) {
-				unique[c] = 0;
-				break;
-			}
-		}
+		c2mask[base[length] = c] = id[length] = 0;
+	}
+	while (c = word[++i]) {
+		unique[c] = !c2mask[c];
+		c2mask[c] |= 1 << i;
 	}
 
 	unseen = 0;
@@ -4041,14 +4037,14 @@ void next()
 				unseen[i] = prev_unseen &= ~(1 << j);
 				continue;
 			}
-			/* Same chars must only appear in one order */
-			c = word[k = i];
-			while (k--)
-				if (word[k] == c)
-					break;
-			if (k >= 0)
+			/* or not unique so far */
+			if ((prev_unseen & (mask = c2mask[c = word[k = i]])) != mask) {
+				/* Same chars must only appear in one order */
+				while (word[--k] != c)
+					continue;
 				if (jd[k] >= j) /* Wrong order */
 					break;
+			}
 			unseen[i] = prev_unseen &= ~(1 << (jd[i] = j));
 		}