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 CFArrayCreate(_:_:_:_:) or CFArrayCreateCopy(_:_:) 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 kCFNull 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 CFArrayGetCount(_:) and CFArrayGetValueAtIndex(_:_:) provide the basis for all other functions in its interface. The CFArrayGetCount(_:) function returns the number of elements in an array; CFArrayGetValueAtIndex(_:_:) 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 CFArrayApplyFunction(_:_:_:_:) lets you apply a function to values in an array, and CFArrayBSearchValues(_:_:_:_:_:) 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 CFArrayRef, and in a function where you see a CFArrayRef 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

func CFArrayCreateCopy(CFAllocator!, CFArray!)

Creates a new immutable array with the values from another array.

Examining an Array

func CFArrayContainsValue(CFArray!, CFRange, UnsafeRawPointer!)

Reports whether or not a value is in an array.

func CFArrayGetCount(CFArray!)

Returns the number of values currently in an array.

func CFArrayGetCountOfValue(CFArray!, CFRange, UnsafeRawPointer!)

Counts the number of times a given value occurs in an array.

func CFArrayGetValueAtIndex(CFArray!, CFIndex)

Retrieves a value at a given index.

Applying a Function to Elements

Getting the CFArray Type ID

func CFArrayGetTypeID()

Returns the type identifier for the CFArray opaque type.

Callbacks

CFArrayApplierFunction

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

CFArrayCopyDescriptionCallBack

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

CFArrayEqualCallBack

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

CFArrayReleaseCallBack

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

CFArrayRetainCallBack

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

Data Types

CFArrayCallBacks

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.