CFArray

Overview

CFArray and its derived mutable type, CFMutableArray, manage ordered collections of values called arrays. CFArray creates static arrays and CFMutableArray creates dynamic arrays.

You create a static array object using either the CFArray​Create(_:​_:​_:​_:​) or CFArray​Create​Copy(_:​_:​) function. These functions return an array containing the values you pass in as arguments. (Note that arrays can’t contain NULL pointers; in most cases, though, you can use the k​CFNull constant instead.) Values are not copied but retained using the retain callback provided when an array was created. Similarly, when a value is removed from an array, it is released using the release callback.

CFArray’s two primitive functions CFArray​Get​Count(_:​) and CFArray​Get​Value​At​Index(_:​_:​) provide the basis for all other functions in its interface. The CFArray​Get​Count(_:​) function returns the number of elements in an array; CFArray​Get​Value​At​Index(_:​_:​) gives you access to an array’s elements by index, with index values starting at 0.

A number of CFArray functions allow you to operate over a range of values in an array, for example CFArray​Apply​Function(_:​_:​_:​_:​) lets you apply a function to values in an array, and CFArray​BSearch​Values(_:​_:​_:​_:​_:​) searches an array for the value that matches its parameter. Recall that a range is defined as {start, length}, therefore to operate over the entire array the range you supply should be {0, N} (where N is the count of the array).

CFArray is “toll-free bridged” with its Cocoa Foundation counterpart, NSArray. This means that the Core Foundation type is interchangeable in function or method calls with the bridged Foundation object. Therefore, in a method where you see an NSArray * parameter, you can pass in a CFArray​Ref, and in a function where you see a CFArray​Ref parameter, you can pass in an NSArray instance. This also applies to concrete subclasses of NSArray. See Toll-Free Bridged Types for more information on toll-free bridging.

Symbols

Creating an Array

Getting the CFArray Type ID

func CFArray​Get​Type​ID()

Returns the type identifier for the CFArray opaque type.

Callbacks

CFArray​Applier​Function

Prototype of a callback function that may be applied to every value in an array.

CFArray​Copy​Description​Call​Back

Prototype of a callback function used to get a description of a value in an array.

CFArray​Equal​Call​Back

Prototype of a callback function used to determine if two values in an array are equal.

CFArray​Release​Call​Back

Prototype of a callback function used to release a value before it’s removed from an array.

CFArray​Retain​Call​Back

Prototype of a callback function used to retain a value being added to an array.

Data Types

CFArray​Call​Backs

Structure containing the callbacks of a CFArray.

CFArray

A reference to an immutable array object.

Constants

Predefined Callback Structures

CFArray provides a predefined callback structure appropriate for use when the values in a CFArray are all CFType-derived objects.