Swift 5.0: 'withUnsafeBytes' is deprecated: use `withUnsafeBytes<R>(...)

Question

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

Answer 1

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) }

(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.

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)