How to use the CFMutableArrray

Question

I am reading a video file using AVFoundation framework and getting the image buffers as CMSampleBuferRef, I added the buffers in CFMutableArrayRef using CFArrayAppendValue() function.

But If I want to retrieve from that array, Is there any way?

Apple document for CFMutableArrayRef gives no method to retrive from array.

Answer 1

In addition to using the APIs Matt pointed out (+1), CFMutableArray is toll-free-bridged with NSMutableArray. you can simply cast an instance of a CFMutableArray to an NSMutableArray and use NSMutableArray's methods (or the other way around). Following the cast to NSMutableArray, you can use -[NSArray objectAtIndex:].

Many Foundation types have CoreFoundation counterparts which are toll free bridged. As a toll free bridged type, the cast does not introduce a promotion or conversion. Think of them as the same type, and that instances may be converted/cast to their CF-NS counterparts without introducing overhead or change to the instance. Technically, implicit reference counting may be introduced if your implementation uses NS-types rather than CF-types under ARC.

This may be useful if you are writing in ObjC, and are more familiar with the ObjC APIs.

Answer 2

You're looking for the CFArray function CFArrayGetValueAtIndex, or something similar. CFMutableArray's "inherit" from CFArrays, and the documentation on CFMutableArray only contains the API that differs from CFArray.

See the docs here.