Is there a way to efficiently access NSArray element contents?

FROM : Brent Fulgham
DATE : Sun Jun 08 20:13:22 2008

I've been enjoying the NSArray/NSMutableArray classes as I work with 
various user interface features for a program I'm working on that 
interacts with a legacy C++ library.

I've recently begun considering how to efficiently display the 
contents of a binary data stream.  Currently I'm appending to an 
NSMutableArray of NSNumber objects, which is great for allowing me to 
bind to some UI elements in close to real time and has provided a 
simple and functional mechanism for text numerical display.

Ideally, I'd like to be able to access a raw binary buffer of data so 
I could for example bind it to something like an OpenGL vector buffer 
for display.  However, unlike an STL vector, I don't think the 
NS[Mutable]Array provides any guarantees of memory organization, nor 
any way to 'unbox' the NSNumber to deal with the internal values.

For example, in the STL, I could make use of the fact that the vector 
template guarantees the storage to be in contiguous memory and 
accessible as raw double values through the address of the first 
element of the vector.  However, I don't think this is possible via 
NSMutableArray and NSNumbers.

Is my only option to periodically sync a buffer of binary double 
values by copying from the NSMutableArray on some periodic basis?

Thanks,

-Brent