Swift中字节数组的NSData [英] NSData from Byte array in Swift

问题描述

我正在尝试从字节数组中创建一个NSData var.

I'm trying to create an NSData var from an array of bytes.

在Obj-C中，我可能已经这样做了:

In Obj-C I might have done this:

NSData *endMarker = [[NSData alloc] initWithBytes:{ 0xFF, 0xD9 }, length: 2]

我无法弄清楚Swift中的等效功能.

I can't figure out a working equivalent in Swift.

推荐答案

NSData具有一个带有bytes指针的初始化程序:init(bytes: UnsafeMutablePointer <Void>, length: Int). UnsafePointer参数可以接受各种不同的东西，包括一个简单的Swift数组，因此您可以使用与Objective-C几乎相同的语法.传递数组时，需要确保将其标识为UInt8数组，否则Swift的类型推断将假定您要创建Int数组.

NSData has an initializer that takes a bytes pointer: init(bytes: UnsafeMutablePointer <Void>, length: Int). An UnsafePointer parameter can accept a variety of different things, including a simple Swift array, so you can use pretty much the same syntax as in Objective-C. When you pass the array, you need to make sure you identify it as a UInt8 array or Swift's type inference will assume you mean to create an Int array.

var endMarker = NSData(bytes: [0xFF, 0xD9] as [UInt8], length: 2)

您可以在Apple的与C进行交互中阅读有关不安全指针参数的更多信息. API 文档.

You can read more about unsafe pointer parameters in Apple's Interacting with C APIs documentation.

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