HowToCreateTollFreeBridgedClass

经常看到toll free bridged，只是大概知道是类型可以相互转换。为了更好的了解，在网上找到了这个资料。保存下来，方便以后查看

 

http://www.cocoadev.com/index.pl?HowToCreateTollFreeBridgedClass

 

The following classes are toll-free bridged:

http://www.cocoadev.com/index.pl?TollFreeBridged

• NSArray = CFArray
• NSMutableArray = CFMutableArray?
• NSCalendar = CFCalendar?
• NSCharacterSet = CFCharacterSet?
• NSMutableCharacterSet? = CFMutableCharacterSet?
• NSData = CFData?
• NSMutableData = CFMutableData?
• NSDate = CFDate?
• NSDictionary = CFDictionary
• NSMutableDictionary = cfmutabledictionary?
• NSNumber = CFNumber
• NSTimer = CFRunLoopTimer?
• NSSet = CFSet?
• NSMutableSet = CFMutableSet?
• NSString = CFString
• NSMutableString = CFMutableString?
• NSUrL = CFURL
• NSTimeZone? = CFTimeZone?
• NSInputStream@L_404_37@ = CFReadStream?
• NSOutputStream? = CFWriteStream?
• disc Recording
  • DRBurn = DRBurnRef?
  • DRErase = DREraseRef?
  • DRDevice = DRDeviceRef?
  • DRTrack = DRTrackRef?
  • DRFile? = DRFileRef?
  • DRFolder? = DRFolderRef? (starting with 10.3)
• NSAttributedString = CFAttributedString?
• NSMutableAttributedString = CFMutableAttributedString?

The following classes are not toll-free bridged:

• NSBundle and CFBundle?
• NSHost and CFHost
• NSRunLoop and CFRunLoop?
• NSNotificationCenter and CFNotificationCenter?
• NSSocket? and CFSocket

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TollFreeBridging is what allows you to take CoreFoundation types and typecast them to Cocoa types (and vice versa).

So,if you have to call a CoreFoundation function that takes a CFString,but you have an NSString,you can just pass it your NSString with:

 

CFStringRef myCFString = (CFStringRef)someNsstring;

And if you need to get an NSString from a CFString,you can do this:

 

NSString* myNsstring = (NSString*)someCFString;

see also: HowToCreateTollFreeBridgedClass

See which classes are TollFreeBridged.