Struct AVAudioTime 

pub struct AVAudioTime { /* private fields */ }

Available on crate feature AVAudioTime only.

Represent a moment in time.

AVAudioTime is used in AVAudioEngine to represent time. Instances are immutable.

A single moment in time may be represented in two different ways:

1. mach_absolute_time(), the system’s basic clock. Commonly referred to as “host time.”
2. audio samples at a particular sample rate

A single AVAudioTime instance may contain either or both representations; it might represent only a sample time, only a host time, or both.

Rationale for using host time: [a] internally we are using AudioTimeStamp, which uses host time, and it seems silly to divide [b] it is consistent with a standard system timing service [c] we do provide conveniences to convert between host ticks and seconds (host time divided by frequency) so client code wanting to do what should be straightforward time computations can at least not be cluttered by ugly multiplications and divisions by the host clock frequency.

See also Apple’s documentation

Implementations

impl AVAudioTime

pub unsafe fn initWithAudioTimeStamp_sampleRate( this: Allocated<Self>, ts: NonNull<AudioTimeStamp>, sample_rate: c_double, ) -> Retained<Self>

Available on crate feature objc2-core-audio-types only.

Safety

ts must be a valid pointer.

pub unsafe fn initWithHostTime( this: Allocated<Self>, host_time: u64, ) -> Retained<Self>

pub unsafe fn initWithSampleTime_atRate( this: Allocated<Self>, sample_time: AVAudioFramePosition, sample_rate: c_double, ) -> Retained<Self>

Available on crate feature AVAudioTypes only.

pub unsafe fn initWithHostTime_sampleTime_atRate( this: Allocated<Self>, host_time: u64, sample_time: AVAudioFramePosition, sample_rate: c_double, ) -> Retained<Self>

Available on crate feature AVAudioTypes only.

pub unsafe fn timeWithAudioTimeStamp_sampleRate( ts: NonNull<AudioTimeStamp>, sample_rate: c_double, ) -> Retained<Self>

Available on crate feature objc2-core-audio-types only.

Safety

ts must be a valid pointer.

pub unsafe fn timeWithHostTime(host_time: u64) -> Retained<Self>

pub unsafe fn timeWithSampleTime_atRate( sample_time: AVAudioFramePosition, sample_rate: c_double, ) -> Retained<Self>

Available on crate feature AVAudioTypes only.

pub unsafe fn timeWithHostTime_sampleTime_atRate( host_time: u64, sample_time: AVAudioFramePosition, sample_rate: c_double, ) -> Retained<Self>

Available on crate feature AVAudioTypes only.

pub unsafe fn hostTimeForSeconds(seconds: NSTimeInterval) -> u64

Convert seconds to host time.

pub unsafe fn secondsForHostTime(host_time: u64) -> NSTimeInterval

Convert host time to seconds.

pub unsafe fn extrapolateTimeFromAnchor( &self, anchor_time: &AVAudioTime, ) -> Option<Retained<AVAudioTime>>

Converts between host and sample time.

Parameter anchorTime: An AVAudioTime with a more complete AudioTimeStamp than that of the receiver (self).

Returns: the extrapolated time

If anchorTime is an AVAudioTime where both host time and sample time are valid, and self is another timestamp where only one of the two is valid, this method returns a new AVAudioTime copied from self and where any additional valid fields provided by the anchor are also valid.

Note that the anchorTime must have both host and sample time valid, and self must have sample rate and at least one of host or sample time valid. Otherwise this method returns nil.

// time0 has a valid audio sample representation, but no host time representation.
AVAudioTime *time0 = [AVAudioTime timeWithSampleTime: 0.0 atRate: 44100.0];
// anchor has a valid host time representation and sample time representation.
AVAudioTime *anchor = [player playerTimeForNodeTime: player.lastRenderTime];
// fill in valid host time representation
AVAudioTime *fullTime0 = [time0 extrapolateTimeFromAnchor: anchor];

pub unsafe fn isHostTimeValid(&self) -> bool

Whether the hostTime property is valid.

This property is not atomic.

Safety

This might not be thread-safe.

pub unsafe fn hostTime(&self) -> u64

The host time.

This property is not atomic.

Safety

This might not be thread-safe.

pub unsafe fn isSampleTimeValid(&self) -> bool

Whether the sampleTime and sampleRate properties are valid.

This property is not atomic.

Safety

This might not be thread-safe.

pub unsafe fn sampleTime(&self) -> AVAudioFramePosition

Available on crate feature AVAudioTypes only.

The time as a number of audio samples, as tracked by the current audio device.

This property is not atomic.

Safety

This might not be thread-safe.

pub unsafe fn sampleRate(&self) -> c_double

The sample rate at which sampleTime is being expressed.

This property is not atomic.

Safety

This might not be thread-safe.

pub unsafe fn audioTimeStamp(&self) -> AudioTimeStamp

Available on crate feature objc2-core-audio-types only.

The time expressed as an AudioTimeStamp structure.

This may be useful for compatibility with lower-level CoreAudio and AudioToolbox API’s.

This property is not atomic.

Safety

This might not be thread-safe.

impl AVAudioTime

Methods declared on superclass NSObject.

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

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<AVAudioTime> for AVAudioTime

fn as_ref(&self) -> &Self

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

impl AsRef<AnyObject> for AVAudioTime

fn as_ref(&self) -> &AnyObject

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

impl AsRef<NSObject> for AVAudioTime

fn as_ref(&self) -> &NSObject

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

impl Borrow<AnyObject> for AVAudioTime

fn borrow(&self) -> &AnyObject

Immutably borrows from an owned value.

impl Borrow<NSObject> for AVAudioTime

fn borrow(&self) -> &NSObject

Immutably borrows from an owned value.

impl ClassType for AVAudioTime

const NAME: &'static str = "AVAudioTime"

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

type Super = NSObject

The superclass of this class.

type ThreadKind = <<AVAudioTime 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 Debug for AVAudioTime

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

Formats the value using the given formatter.

impl Deref for AVAudioTime

type Target = NSObject

The resulting type after dereferencing.

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

Dereferences the value.

impl Hash for AVAudioTime

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 AVAudioTime

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

where Self: Sized,

Increment the reference count of the receiver.

impl NSObjectProtocol for AVAudioTime

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 PartialEq for AVAudioTime

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 AVAudioTime

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

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

impl DowncastTarget for AVAudioTime

impl Eq for AVAudioTime

impl Send for AVAudioTime

impl Sync for AVAudioTime