当我将一个字节数组从Swift转换为Objective-C时应该使用什么数据类型

I have a project where I write the production code in Swift and my unit tests in Objective-C (because I'm using OCMock I write my tests in Objective-C).

我有一个项目，用Swift编写产品代码，用Objective-C编写单元测试(因为我使用OCMock，所以我用Objective-C编写测试)。

What I'm trying to do is to write a Buffer object where the writeBytes method takes a Byte array and a length, like this:

我要做的是编写一个缓冲区对象，其中writeBytes方法使用一个字节数组和一个长度，如下所示:

func writeBytes(data: [Byte], length: Int)

In my unit test target I want to test this method, but the problem is that it won't convert this method to Objective-C. By looking in my -Swift.h file I see the following:

在单元测试目标中，我想测试这个方法，但问题是它不会将这个方法转换为Objective-C。通过看我的-斯威夫特。h文件如下:

@interface Buffer : Object
@property (nonatomic) NSInteger capacity;
@property (nonatomic) NSInteger size;
- (instancetype)initWithCapacity:(NSInteger)capacity OBJC_DESIGNATED_INITIALIZER;
- (void)reset;
- (NSInteger)size;
- (BOOL)isFilled;
- (BOOL)isEmpty;
@end

As you can see the writeBytes method is missing. I've tried different data types to see if it appears: UInt8, UnsafePointer<UInt8>, but none of them work.

如您所见，writeBytes方法丢失了。我尝试了不同的数据类型来查看它是否出现:UInt8、UnsafePointer ，但它们都不起作用。

For the sake of debugging I tried using a String array and that gets converted to Objective-C without any problems.

为了调试，我尝试使用一个字符串数组，它被转换为Objective-C，没有任何问题。

What data type should I use for my Byte array to make the writeBytes method available in Objective-C?

我应该使用什么数据类型的字节数组来使writeBytes方法在Objective-C中可用?

2 个解决方案

#1

The Swift type [Byte] is not representable in Objective-C, but you can work with a pointer to the bytes:

Swift类型[Byte]在Objective-C中不能表示，但是可以使用指向字节的指针:

func writeBytes(data: ConstUnsafePointer<Byte>, length: Int) { ... }

var data : [Byte] = [1, 2, 3]
writeBytes(data, length: data.count)

This mapped to Objective-C as

它映射到Objective-C as

- (void)writeBytes:(Byte const *)data length:(NSInteger)length;

so that you can call it like

你可以这样称呼它

Byte data[] = {1, 2, 3};
[buffer writeBytes:data length:3];

#2

Use NSData. You can create one from an array of [UInt8] in Swift as:

使用NSData。您可以从[UInt8]的数组中创建一个，如:

import Foundation
var u8s = [UInt8]()
// ...
var data = NSData(bytes:&u8s, length:u8s.count)

FYI this is the opposite of Swift - converting from ConstUnsafePointer<()> where the questioner was looking for the way to convert NSData to [UInt8].

提示:这与从ConstUnsafePointer<()>到Swift的转换是相反的，在这个转换中，提问者正在寻找将NSData转换为[UInt8]的方法。

#1