1  //
 2  //  NSConstantString.m
 3  //  CoreFoundation
 4  //
 5  //  Copyright (c) 2014 Apportable. All rights reserved.
 6  //
 7  
 8  #import "NSStringInternal.h"
 9  
10  #import <objc/runtime.h>
11  
12  @implementation __NSCFConstantString
13  
14  SINGLETON_RR()
15  
16  - (id)copyWithZone:(NSZone *)zone
17  {
18      return self;
19  }
20  
21  - (BOOL)isKindOfClass:(Class)cls
22  {
23      if ([super isKindOfClass: cls]) {
24          return YES;
25      }
26      return cls == objc_lookUpClass("NSString");
27  }
28  
29  @end