[Modify] Polish it

websocket-sharp/Ext.cs

@@ -516,19 +516,28 @@ namespace WebSocketSharp
     internal static bool IsText (this string value)
     {
       var len = value.Length;
+
       for (var i = 0; i < len; i++) {
         var c = value[i];
-        if (c < 0x20 && !"\r\n\t".Contains (c))
-          return false;
+        if (c < 0x20) {
+          if (!"\r\n\t".Contains (c))
+            return false;
+
+          if (c == '\n') {
+            i++;
+            if (i == len)
+              break;
+
+            c = value[i];
+            if (!" \t".Contains (c))
+              return false;
+          }
+
+          continue;
+        }
 
         if (c == 0x7f)
           return false;
-
-        if (c == '\n' && ++i < len) {
-          c = value[i];
-          if (!" \t".Contains (c))
-            return false;
-        }
       }
 
       return true;