Question

I need to be able to add and remove an arbitrary number of points to an array. In C++ I could do this easily using vector which allows me to add and remove items of any type.

I know I could store structs in an NSMutableArray using the NSValue class, but I would prefer a faster method than creating and destroy NSValue objects constantly. Is there something similar to the vector class in Objective-C or is there another way to add and remove my structs to arrays (I would prefer not to use Objective C++)? Or am I stuck with NSMutableArray and NSValue.

EDIT: NSMutableData seems like a possible solution.

Answer 1

If you were not targetting iOS, I would suggest NSPointerArray, which obviates the necessity of wrapping your raw struct datatypes in NSValue containers. However, this class is (unfortunately) not available on iOS.

Apple acknowledge this in their NSArray documentation for iOS, under the title Alternatives to Subclassing.

Before making a custom class of NSArray, investigate NSPointerArray and the corresponding Core Foundation type, CFArray Reference. Because NSArray and CFArray are “toll-free bridged,” you can substitute a CFArray object for a NSArray object in your code (with appropriate casting). Although they are corresponding types, CFArray and NSArray do not have identical interfaces or implementations, and you can sometimes do things with CFArray that you cannot easily do with NSArray. For example, CFArray provides a set of callbacks, some of which are for implementing custom retain-release behavior. If you specify NULL implementations for these callbacks, you can easily get a non-retaining array.

In other words, you can indirectly create an NSArray (or mutable counterpart) that directly holds your non-object datatypes.