cocoa - 如何转义 NSString 中的 unicode 字符？

Question

当我将 NSString 存储在某个 NSDictionary 中并将该字典记录到控制台时，如下所示:

NSString *someString = @"Münster";  
NSDictionary *someDict = [ NSDictionary dictionaryWithObjectsAndKeys: 
    someString, @"thestring" ];
NSLog ( @"someDict: %@", [ someDict description ] );

控制台输出如下所示:

unicode_test[3621:903] someDict:
{
    thestring = "M\U00fcnster";
}

字符串的 unicode 字符已转义。有没有任何方法可以将 NSString 转换为这种转义表示形式？

Answer 1

可以使用给定字符串的 UniChar 字符串表示形式的循环来解决该问题。作为 NSString 上的扩展实现，它看起来像这样:

- (NSString *) escapedUnicode  
{  
    NSMutableString *uniString = [ [ NSMutableString alloc ] init ];  
    UniChar *uniBuffer = (UniChar *) malloc ( sizeof(UniChar) * [ self length ] );  
    CFRange stringRange = CFRangeMake ( 0, [ self length ] );  

    CFStringGetCharacters ( (CFStringRef)self, stringRange, uniBuffer );  

    for ( int i = 0; i < [ self length ]; i++ ) {  
        if ( uniBuffer[i] > 0x7e )  
            [ uniString appendFormat: @"\\u%04x", uniBuffer[i] ];  
        else  
            [ uniString appendFormat: @"%c", uniBuffer[i] ];  
    }  

    free ( uniBuffer );  

    NSString *retString = [ NSString stringWithString: uniString ];  
    [ uniString release ];  

    return retString;  
}