Struct TKBERTLVRecord

Source

pub struct TKBERTLVRecord { /* private fields */ }

Available on crate feature TKTLVRecord only.

Expand description

TKBERTLVRecord implements encoding using BER-TLV encoding rules. It is able to parse BER-encoded data and always produces DER-encoded data. No interpretation of tag values is made, all values are treated only as NSData irrespective of the tag.

Implementations§

Source §

impl TKBERTLVRecord

Source

pub unsafe fn dataForTag(tag: TKTLVTag) -> Retained<NSData>

Encodes tag using BER-TLV tag encoding rules.

Parameter tag: Tag value to encode

Returns: Binary block containing encoded tag value.

Source

pub unsafe fn initWithTag_value( this: Allocated<Self>, tag: TKTLVTag, value: &NSData, ) -> Retained<Self>

Creates TLV record with specified tag and value.

Parameter tag: Tag value for the new record.

Parameter value: Value for the new record.

Returns: Newly created TLV record.

Source

pub unsafe fn initWithTag_records( this: Allocated<Self>, tag: TKTLVTag, records: &NSArray<TKTLVRecord>, ) -> Retained<Self>

Creates TKBERTLVRecord with specified tag and array of children TKTLVRecord instances as subrecords.

Parameter tag: Tag value for the new record.

Parameter records: Array of TKTLVRecord instances serving as subrecords of this record.

Returns: Newly created TLV record.

Source §

impl TKBERTLVRecord

Methods declared on superclass TKTLVRecord.

Source

pub unsafe fn recordFromData(data: &NSData) -> Option<Retained<Self>>

Parses TLV record from data block

Parameter data: Data block containing serialized form of TLV record.

Returns: newly parsed record instance or nil if data do not represent valid record.

Source

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

Source §

impl TKBERTLVRecord

Methods declared on superclass NSObject.

Source

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

Methods from Deref<Target = TKTLVRecord>§

Source

pub unsafe fn tag(&self) -> TKTLVTag

Tag value of the record.

Source

pub unsafe fn value(&self) -> Retained<NSData>

Value field of the record.

Source

pub unsafe fn data(&self) -> Retained<NSData>

Data object containing whole encoded record, including tag, length and value.

Methods from Deref<Target = NSObject>§

Source

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

Handle messages the object doesn’t recognize.

See Apple’s documentation for details.

Methods from Deref<Target = AnyObject>§

Source

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

Available on crate feature TKToken only.

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());

Source

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

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

Available on crate feature TKToken only.

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.

Source

pub fn downcast_ref<T>(&self) -> Option<&T>
where T: DowncastTarget,

Available on crate feature TKToken only.

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`
    }
}