Struct GKRandomSource 

pub struct GKRandomSource { /* private fields */ }

Available on crate feature GKRandomSource only.

A concrete random source that can generate random numbers. The implementation details are up to the system and if a particular algorithm is needed then use one of the provided subclasses.

For certain specialized applications a shared system source may be needed and for those instances there is a wrapped interface over arc4random_*, accessible via +[GKRandomSource sharedRandom].

See: GKARC4RandomSource

See: GKLinearCongruentialRandomSource

See: GKMersenneTwisterRandomSource

See: GKRandomSource.systemRandom

See also Apple’s documentation

Implementations

impl GKRandomSource

pub unsafe fn init(this: Allocated<Self>) -> Retained<Self>

Creates a new random source initialized using bits from an entropy source like SecRandomCopyBytes. When used directly from the base class; this source is deterministic and performant but the underlying implementation details are not specified. Use a subclass with a specific algorithm implementation guaranteed if your application requires very stringent random source charateristics.

See: GKARC4RandomSource

See: GKLinearCongruentialRandomSource

See: GKMersenneTwisterRandomSource

pub unsafe fn initWithCoder( this: Allocated<Self>, a_decoder: &NSCoder, ) -> Retained<Self>

Deserializes a random source from an NSCoder. All random sources support coding for serializing and deserializing the state of the random source. Each subclass has its own contract for what parts of the state is preserved when serialized but the general contract is that a serialized source must generate the same sequence of values as the original source would from the instant it was serialized.

Note that the sharedRandom instance is an exception as it is explicitly seedless and a shared singleton instance. When serialized and deserialized it will return the current sharedRandom instance instead.

Safety

a_decoder possibly has further requirements.

pub unsafe fn sharedRandom() -> Retained<GKRandomSource>

Returns a shared instance of a random source that uses the system’s underlying random source. Using this instance modifies the outcome of future calls to the arc4random family of C calls. It is also affected by calls to the C apis and should not be used for sources that are intended to be deterministic.

Note that while it may seem semantically similar to a GKARC4RandomSource, this is not a drop in replacement.

pub unsafe fn arrayByShufflingObjectsInArray( &self, array: &NSArray, ) -> Retained<NSArray>

Returns a shuffled instance of the given array. The objects in the array are shuffled based on a Fisher-Yates shuffle.

Any random, be it custom, source or a distribution, that can provide a number with an upper bound of at least the array.count is suitable for this shuffle.

Safety

array generic should be of the correct type.

impl GKRandomSource

Methods declared on superclass NSObject.

pub unsafe fn new() -> Retained<Self>

Methods from Deref<Target = NSObject>

pub fn doesNotRecognizeSelector(&self, sel: Sel) -> !

Handle messages the object doesn’t recognize.

See Apple’s documentation for details.

Methods from Deref<Target = AnyObject>

pub fn class(&self) -> &'static AnyClass

Dynamically find the class of this object.

Panics

May panic if the object is invalid (which may be the case for objects returned from unavailable init/new methods).

Example

Check that an instance of NSObject has the precise class NSObject.

use objc2::ClassType;
use objc2::runtime::NSObject;

let obj = NSObject::new();
assert_eq!(obj.class(), NSObject::class());

pub unsafe fn get_ivar<T>(&self, name: &str) -> &T

where T: Encode,

👎Deprecated: this is difficult to use correctly, use Ivar::load instead.

Use Ivar::load instead.

Safety

The object must have an instance variable with the given name, and it must be of type T.

See Ivar::load_ptr for details surrounding this.

pub fn downcast_ref<T>(&self) -> Option<&T>

where T: DowncastTarget,

Attempt to downcast the object to a class of type T.

This is the reference-variant. Use Retained::downcast if you want to convert a retained object to another type.

Mutable classes

Some classes have immutable and mutable variants, such as NSString and NSMutableString.

When some Objective-C API signature says it gives you an immutable class, it generally expects you to not mutate that, even though it may technically be mutable “under the hood”.

So using this method to convert a NSString to a NSMutableString, while not unsound, is generally frowned upon unless you created the string yourself, or the API explicitly documents the string to be mutable.

See Apple’s documentation on mutability and on isKindOfClass: for more details.

Generic classes

Objective-C generics are called “lightweight generics”, and that’s because they aren’t exposed in the runtime. This makes it impossible to safely downcast to generic collections, so this is disallowed by this method.

You can, however, safely downcast to generic collections where all the type-parameters are AnyObject.

Panics

This works internally by calling isKindOfClass:. That means that the object must have the instance method of that name, and an exception will be thrown (if CoreFoundation is linked) or the process will abort if that is not the case. In the vast majority of cases, you don’t need to worry about this, since both root objects NSObject and NSProxy implement this method.

Examples

Cast an NSString back and forth from NSObject.

use objc2::rc::Retained;
use objc2_foundation::{NSObject, NSString};

let obj: Retained<NSObject> = NSString::new().into_super();
let string = obj.downcast_ref::<NSString>().unwrap();
// Or with `downcast`, if we do not need the object afterwards
let string = obj.downcast::<NSString>().unwrap();

Try (and fail) to cast an NSObject to an NSString.

use objc2_foundation::{NSObject, NSString};

let obj = NSObject::new();
assert!(obj.downcast_ref::<NSString>().is_none());

Try to cast to an array of strings.

use objc2_foundation::{NSArray, NSObject, NSString};

let arr = NSArray::from_retained_slice(&[NSObject::new()]);
// This is invalid and doesn't type check.
let arr = arr.downcast_ref::<NSArray<NSString>>();

This fails to compile, since it would require enumerating over the array to ensure that each element is of the desired type, which is a performance pitfall.

Downcast when processing each element instead.

use objc2_foundation::{NSArray, NSObject, NSString};

let arr = NSArray::from_retained_slice(&[NSObject::new()]);

for elem in arr {
    if let Some(data) = elem.downcast_ref::<NSString>() {
        // handle `data`
    }
}

Trait Implementations

impl AsRef<AnyObject> for GKRandomSource

fn as_ref(&self) -> &AnyObject

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<GKRandomSource> for GKARC4RandomSource

fn as_ref(&self) -> &GKRandomSource

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<GKRandomSource> for GKLinearCongruentialRandomSource

fn as_ref(&self) -> &GKRandomSource

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<GKRandomSource> for GKMersenneTwisterRandomSource

fn as_ref(&self) -> &GKRandomSource

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<GKRandomSource> for GKRandomSource

fn as_ref(&self) -> &Self

Converts this type into a shared reference of the (usually inferred) input type.

impl AsRef<NSObject> for GKRandomSource

fn as_ref(&self) -> &NSObject

Converts this type into a shared reference of the (usually inferred) input type.

impl Borrow<AnyObject> for GKRandomSource

fn borrow(&self) -> &AnyObject

Immutably borrows from an owned value.

impl Borrow<GKRandomSource> for GKARC4RandomSource

fn borrow(&self) -> &GKRandomSource

Immutably borrows from an owned value.

impl Borrow<GKRandomSource> for GKLinearCongruentialRandomSource

fn borrow(&self) -> &GKRandomSource

Immutably borrows from an owned value.

impl Borrow<GKRandomSource> for GKMersenneTwisterRandomSource

fn borrow(&self) -> &GKRandomSource

Immutably borrows from an owned value.

impl Borrow<NSObject> for GKRandomSource

fn borrow(&self) -> &NSObject

Immutably borrows from an owned value.

impl ClassType for GKRandomSource

const NAME: &'static str = "GKRandomSource"

The name of the Objective-C class that this type represents.

type Super = NSObject

The superclass of this class.

type ThreadKind = <<GKRandomSource as ClassType>::Super as ClassType>::ThreadKind

Whether the type can be used from any thread, or from only the main thread.

fn class() -> &'static AnyClass

Get a reference to the Objective-C class that this type represents.

fn as_super(&self) -> &Self::Super

Get an immutable reference to the superclass.

impl CopyingHelper for GKRandomSource

type Result = GKRandomSource

The immutable counterpart of the type, or Self if the type has no immutable counterpart.

impl Debug for GKRandomSource

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Deref for GKRandomSource

type Target = NSObject

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl GKRandom for GKRandomSource

unsafe fn nextInt(&self) -> NSInteger

where Self: Sized + Message,

Returns the next integer in the random sequence and moves ahead to the next one. The value is in the range of [INT32_MIN, INT32_MAX]. The lower bits are not guaranteed to be random so please use another property for simple choices.

unsafe fn nextIntWithUpperBound(&self, upper_bound: NSUInteger) -> NSUInteger

where Self: Sized + Message,

Returns the next unsigned value in the random sequence that is less than upperBound. The value is in the range of [0, upperBound). Thus the value never equals or exceeeds upperBound. The unsigned nature and upper bound allows implementations to use logical shifts to return a value whose lower bits are more random than a similar call to nextInt.

unsafe fn nextUniform(&self) -> c_float

where Self: Sized + Message,

Returns the next uniform float in the random sequence and moves ahead to the next one. The value is in the range of [0.0, 1.0]. There is no weighting across the range so remapping this with a curve may give the best sampling distribution for your algorithm.

unsafe fn nextBool(&self) -> bool

where Self: Sized + Message,

Returns the next true or false value in the random sequence and moves ahead to the next one. The value is either nonzero (true) or zero (false). Use this for simple boolean switches in logic that don’t require fuzzy evaluation. For fuzzy evaluation use nextUniform.

impl Hash for GKRandomSource

fn hash<H: Hasher>(&self, state: &mut H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl Message for GKRandomSource

fn retain(&self) -> Retained<Self>

where Self: Sized,

Increment the reference count of the receiver.

impl NSCoding for GKRandomSource

unsafe fn encodeWithCoder(&self, coder: &NSCoder)

where Self: Sized + Message,

Safety

unsafe fn initWithCoder( this: Allocated<Self>, coder: &NSCoder, ) -> Option<Retained<Self>>

where Self: Sized + Message,

Safety

impl NSCopying for GKRandomSource

fn copy(&self) -> Retained<Self::Result>

where Self: Sized + Message + CopyingHelper,

Returns a new instance that’s a copy of the receiver.

unsafe fn copyWithZone(&self, zone: *mut NSZone) -> Retained<Self::Result>

where Self: Sized + Message + CopyingHelper,

Returns a new instance that’s a copy of the receiver.

impl NSObjectProtocol for GKRandomSource

fn isEqual(&self, other: Option<&AnyObject>) -> bool

where Self: Sized + Message,

Check whether the object is equal to an arbitrary other object.

fn hash(&self) -> usize

where Self: Sized + Message,

An integer that can be used as a table address in a hash table structure.

fn isKindOfClass(&self, cls: &AnyClass) -> bool

where Self: Sized + Message,

Check if the object is an instance of the class, or one of its subclasses.

fn is_kind_of<T>(&self) -> bool

where T: ClassType, Self: Sized + Message,

👎Deprecated: use isKindOfClass directly, or cast your objects with AnyObject::downcast_ref

Check if the object is an instance of the class type, or one of its subclasses.

fn isMemberOfClass(&self, cls: &AnyClass) -> bool

where Self: Sized + Message,

Check if the object is an instance of a specific class, without checking subclasses.

fn respondsToSelector(&self, aSelector: Sel) -> bool

where Self: Sized + Message,

Check whether the object implements or inherits a method with the given selector.

fn conformsToProtocol(&self, aProtocol: &AnyProtocol) -> bool

where Self: Sized + Message,

Check whether the object conforms to a given protocol.

fn description(&self) -> Retained<NSObject>

where Self: Sized + Message,

A textual representation of the object.

fn debugDescription(&self) -> Retained<NSObject>

where Self: Sized + Message,

A textual representation of the object to use when debugging.

fn isProxy(&self) -> bool

where Self: Sized + Message,

Check whether the receiver is a subclass of the NSProxy root class instead of the usual NSObject.

fn retainCount(&self) -> usize

where Self: Sized + Message,

The reference count of the object.

impl NSSecureCoding for GKRandomSource

fn supportsSecureCoding() -> bool

where Self: Sized + ClassType,

impl PartialEq for GKRandomSource

fn eq(&self, other: &Self) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl RefEncode for GKRandomSource

const ENCODING_REF: Encoding = <NSObject as ::objc2::RefEncode>::ENCODING_REF

The Objective-C type-encoding for a reference of this type.

impl DowncastTarget for GKRandomSource

impl Eq for GKRandomSource