Unescape unicode string for debug purposes. Convert \Uabcd, \\Uabcd, \uabcd, \\uabcd to it's symbol representation (fe: "\\U002E\\U002C" to ".,"). Useful for NSLog'ing NSManagedObjects.

Unescape unicode string

/*
 This one may be not optimal, first solution, but helps with NSLogs.
 
 So you can have:
  NSManagedObject *object = ...
  // No \\Uabcd's in log
  NSLog(@"object = %@", [[object debugDescription] unicodeUnescape]);
*/


@interface NSString (Unescape)
- (NSMutableString *)unicodeUnescape;
@end

@implementation NSString (Unescape)
/**
 Creates unescaped string based on reciever. Does not modify receiver.
 Takes \Uabcd, \\Uabcd, \uabcd, \\uabcd, for example converts "\\U002E\\U002C" to ".,".
 
 @note may return exact same string from self, if it's unable to create a regexp (which is
 probably possible if API changes)
 
 @return Newly created NSMutableString
 */
- (NSMutableString *)unicodeUnescape
{
    NSError *error = nil;
    NSRegularExpression *regexp = [NSRegularExpression regularExpressionWithPattern:@"(\\\\{1,2})(U|u)([0-9a-fA-F]{4})"
                                                                            options:0
                                                                              error:&error];
    
    if(error)
    {
        NSLog(@"%s, unable to create regexp", __PRETTY_FUNCTION__);
        return [self mutableCopy];
    }
    
    // replace to make characters be of \uabcd format
    NSMutableString *mutableSelf = [self mutableCopy];
    [regexp replaceMatchesInString:mutableSelf
                           options:NSMatchingReportProgress
                             range:NSMakeRange(0, [mutableSelf length])
                      withTemplate:@"\\\\u$3"];
    
    // transform to readable representation
    CFStringRef transform = CFSTR("Any-Hex/Java");
    CFStringTransform((__bridge CFMutableStringRef)mutableSelf, NULL, transform, YES);
    
    return mutableSelf;
}
@end