Swift 5.0:不推荐使用“withUnsafeBytes":使用“withUnsafeBytes<R>(...) [英] Swift 5.0: 'withUnsafeBytes' is deprecated: use `withUnsafeBytes<R>(...)

问题描述

我之前在 Swift 4.2 中使用过这段代码来生成一个 id:

I previously used this code in Swift 4.2 to generate an id:

public static func generateId() throws -> UInt32 {
    let data: Data = try random(bytes: 4)
    let value: UInt32 = data.withUnsafeBytes { $0.pointee } // deprecated warning!
    return value // + some other stuff 
}

withUnsafeBytes 在 Swift 5.0 中已弃用.我该如何解决这个问题?

withUnsafeBytes is deprecated on Swift 5.0. How can I solve this?

推荐答案

在 Swift 5 中，Data 的 withUnsafeBytes() 方法用一个(无类型的)<代码>UnsafeRawBufferPointer，你可以load()原始内存中的值:

In Swift 5 the withUnsafeBytes() method of Data calls the closure with an (untyped) UnsafeRawBufferPointer, and you can load() the value from the raw memory:

let value = data.withUnsafeBytes { $0.load(as: UInt32.self) }

(比较 如何以明确定义的方式使用 Data.withUnsafeBytes? 在 Swift 论坛中).请注意，这要求内存在 4 字节边界上对齐.有关替代方案，请参阅往返 Swift 数字类型到/从数据.

(compare How to use Data.withUnsafeBytes in a well-defined manner? in the Swift forum). Note that this requires that the memory is aligned on a 4-byte boundary. For alternatives see round trip Swift number types to/from Data.

另请注意，从 Swift 4.2 开始，您只需使用新的 Random API:

Note also that as of Swift 4.2 you can create a random 32-bit integer simply using the new Random API:

let randomId = UInt32.random(in: .min ... .max)

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