fix dead loop if shell character is invalidate

src/kit/shell/src/shellEngine.c

@@ -565,9 +565,12 @@ static void shellPrintNChar(const char *str, int length, int width) {
     if (bytes <= 0) {
       break;
     }
+    if (pos + bytes > length) {
+      break;
+    }
     int w = 0;
 #ifdef WINDOWS
-    w = bytes;
+    w = bytes;gdn
 #else
     if(*(str + pos) == '\t' || *(str + pos) == '\n' || *(str + pos) == '\r'){
       w = bytes;
@@ -575,15 +578,11 @@ static void shellPrintNChar(const char *str, int length, int width) {
       w = wcwidth(wc);
     }
 #endif
+    pos += bytes;
     if (w <= 0) {
       continue;
     }
 
-    pos += bytes;
-    if (pos > length) {
-      break;
-    }
-
     if (width <= 0) {
       printf("%lc", wc);
       continue;