Struct AVAudioFile

#[repr(C)]
pub struct AVAudioFile { /* private fields */ }

Available on crate feature AVAudioFile only.

An audio file opened for reading or writing.

Regardless of the file’s actual format, reading and writing the file is done via AVAudioPCMBuffer objects, containing samples in an AVAudioCommonFormat, referred to as the file’s “processing format.” Conversions are performed to and from the file’s actual format.

Reads and writes are always sequential, but random access is possible by setting the framePosition property.

See also Apple’s documentation

Implementations

impl AVAudioFile

pub unsafe fn initForReading_error( this: Allocated<Self>, file_url: &NSURL, ) -> Result<Retained<Self>, Retained<NSError>>

Open a file for reading.

Parameter fileURL: the file to open

Parameter outError: on exit, if an error occurs, a description of the error

This opens the file for reading using the standard format (deinterleaved floating point).

pub unsafe fn initForReading_commonFormat_interleaved_error( this: Allocated<Self>, file_url: &NSURL, format: AVAudioCommonFormat, interleaved: bool, ) -> Result<Retained<Self>, Retained<NSError>>

Available on crate feature AVAudioFormat only.

Open a file for reading, using a specified processing format.

Parameter fileURL: the file to open

Parameter format: the processing format to use when reading from the file

Parameter interleaved: whether to use an interleaved processing format

Parameter outError: on exit, if an error occurs, a description of the error

pub unsafe fn initForWriting_settings_error( this: Allocated<Self>, file_url: &NSURL, settings: &NSDictionary<NSString, AnyObject>, ) -> Result<Retained<Self>, Retained<NSError>>

Open a file for writing.

Parameter fileURL: the path at which to create the file

Parameter settings: the format of the file to create (See AVAudioRecorder.) For linear PCM, only interleaved formats are supported for the saved file, non interleaved setting will be ignored and a warning is shown.

Parameter outError: on exit, if an error occurs, a description of the error

The file type to create can be set through the corresponding settings key. If not set, it will be inferred from the file extension. Will overwrite a file at the specified URL if a file exists.

This opens the file for writing using the standard format (deinterleaved floating point).

pub unsafe fn initForWriting_settings_commonFormat_interleaved_error( this: Allocated<Self>, file_url: &NSURL, settings: &NSDictionary<NSString, AnyObject>, format: AVAudioCommonFormat, interleaved: bool, ) -> Result<Retained<Self>, Retained<NSError>>

Available on crate feature AVAudioFormat only.

Open a file for writing.

Parameter fileURL: the path at which to create the file

Parameter settings: the format of the file to create (See AVAudioRecorder.) For linear PCM, only interleaved formats are supported for the saved file, non interleaved setting will be ignored and a warning is shown.

Parameter format: the processing format to use when writing to the file.

Parameter interleaved: whether to use an interleaved processing format

Parameter outError: on exit, if an error occurs, a description of the error

The file type to create can be set through the corresponding settings key. If not set, it will be inferred from the file extension. Will overwrite a file at the specified URL if a file exists.

pub unsafe fn close(&self)

Close the audio file.

The underlying file will be closed if open.

• It is normally unnecessary to close a file opened for reading (it will be automatically closed when the object is released)
• It is only necessary to close a file opened for writing in order to achieve specific control over when the file’s header is updated.

Note: Once closed, further file read or write operations will fail with kAudio_FileNotFoundError.

pub unsafe fn readIntoBuffer_error( &self, buffer: &AVAudioPCMBuffer, ) -> Result<(), Retained<NSError>>

Available on crate feature AVAudioBuffer only.

Read an entire buffer.

Parameter buffer: The buffer into which to read from the file. Its format must match the file’s processing format.

Parameter outError: on exit, if an error occurs, a description of the error

Returns: YES for success.

Reading sequentially from framePosition, attempts to fill the buffer to its capacity. On return, the buffer’s length indicates the number of sample frames successfully read.

pub unsafe fn readIntoBuffer_frameCount_error( &self, buffer: &AVAudioPCMBuffer, frames: AVAudioFrameCount, ) -> Result<(), Retained<NSError>>

Available on crate features AVAudioBuffer and AVAudioTypes only.

Read a portion of a buffer.

Parameter frames: The number of frames to read.

Parameter buffer: The buffer into which to read from the file. Its format must match the file’s processing format.

Parameter outError: on exit, if an error occurs, a description of the error

Returns: YES for success.

Like readIntoBuffer:error:, but can be used to read fewer frames than buffer.frameCapacity.

pub unsafe fn writeFromBuffer_error( &self, buffer: &AVAudioPCMBuffer, ) -> Result<(), Retained<NSError>>

Available on crate feature AVAudioBuffer only.

Write a buffer.

Parameter buffer: The buffer from which to write to the file. Its format must match the file’s processing format.

Parameter outError: on exit, if an error occurs, a description of the error

Returns: YES for success.

Writes sequentially. The buffer’s frameLength signifies how much of the buffer is to be written.

pub unsafe fn isOpen(&self) -> bool

Whether the file is open or not.

pub unsafe fn url(&self) -> Retained<NSURL>

The URL the file is reading or writing.

pub unsafe fn fileFormat(&self) -> Retained<AVAudioFormat>

Available on crate feature AVAudioFormat only.

The on-disk format of the file.

pub unsafe fn processingFormat(&self) -> Retained<AVAudioFormat>

Available on crate feature AVAudioFormat only.

The processing format of the file.

pub unsafe fn length(&self) -> AVAudioFramePosition

Available on crate feature AVAudioTypes only.

The number of sample frames in the file.

Note: this can be expensive to compute for the first time.

pub unsafe fn framePosition(&self) -> AVAudioFramePosition

Available on crate feature AVAudioTypes only.

The position in the file at which the next read or write will occur.

Set framePosition to perform a seek before a read or write. A read or write operation advances the frame position by the number of frames read or written.

pub unsafe fn setFramePosition(&self, frame_position: AVAudioFramePosition)

Available on crate feature AVAudioTypes only.

Setter for framePosition.

impl AVAudioFile

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.

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<AVAudioFile> for AVAudioFile

fn as_ref(&self) -> &Self

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

impl AsRef<AnyObject> for AVAudioFile

fn as_ref(&self) -> &AnyObject

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

impl AsRef<NSObject> for AVAudioFile

fn as_ref(&self) -> &NSObject

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

impl Borrow<AnyObject> for AVAudioFile

fn borrow(&self) -> &AnyObject

Immutably borrows from an owned value.

impl Borrow<NSObject> for AVAudioFile

fn borrow(&self) -> &NSObject

Immutably borrows from an owned value.

impl ClassType for AVAudioFile

const NAME: &'static str = "AVAudioFile"

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

type Super = NSObject

The superclass of this class.

type ThreadKind = <<AVAudioFile 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 AVAudioFile

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

Formats the value using the given formatter.

impl Deref for AVAudioFile

type Target = NSObject

The resulting type after dereferencing.

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

Dereferences the value.

impl Hash for AVAudioFile

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 AVAudioFile

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

where Self: Sized,

Increment the reference count of the receiver.

impl NSObjectProtocol for AVAudioFile

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 AVAudioFile

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 AVAudioFile

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

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

impl DowncastTarget for AVAudioFile

impl Eq for AVAudioFile