-Code cleanup

Src/Newtonsoft.Json/Utilities/StringUtils.cs

@@ -60,8 +60,15 @@ namespace Newtonsoft.Json.Utilities
             return format.FormatWith(provider, new[] { arg0, arg1, arg2 });
         }
 
-        public static string FormatWith(this string format, IFormatProvider provider, params object[] args)
+        public static string FormatWith(this string format, IFormatProvider provider, object arg0, object arg1, object arg2, object arg3)
         {
+            return format.FormatWith(provider, new[] { arg0, arg1, arg2, arg3 });
+        }
+
+        private static string FormatWith(this string format, IFormatProvider provider, params object[] args)
+        {
+            // leave this a private to force code to use an explicit overload
+            // avoids stack memory being reserved for the object array
             ValidationUtils.ArgumentNotNull(format, "format");
 
             return string.Format(provider, format, args);
@@ -155,20 +162,16 @@ namespace Newtonsoft.Json.Utilities
             if (!char.IsUpper(s[0]))
                 return s;
 
-            int length = s.Length;
             char[] chars = s.ToCharArray();
-#if !(NETFX_CORE || PORTABLE)
-            CultureInfo invariantCulture = CultureInfo.InvariantCulture;
-#endif
 
-            for (int i = 0; i < length; i++)
+            for (int i = 0; i < chars.Length; i++)
             {
-                bool hasNext = (i + 1 < length);
+                bool hasNext = (i + 1 < chars.Length);
                 if (i > 0 && hasNext && !char.IsUpper(chars[i + 1]))
                     break;
 
 #if !(NETFX_CORE || PORTABLE)
-                chars[i] = char.ToLower(chars[i], invariantCulture);
+                chars[i] = char.ToLower(chars[i], CultureInfo.InvariantCulture);
 #else
                 chars[i] = char.ToLower(chars[i]);
 #endif
@@ -197,13 +200,12 @@ namespace Newtonsoft.Json.Utilities
 
         public static bool StartsWith(this string source, char value)
         {
-            return (source.Length != 0 && source[0] == value);
+            return (source.Length > 0 && source[0] == value);
         }
 
         public static bool EndsWith(this string source, char value)
         {
-            int sourceLen = source.Length;
-            return (sourceLen != 0 && source[sourceLen - 1] == value);
+            return (source.Length > 0 && source[source.Length - 1] == value);
         }
     }
 }