Question

从Objective-C，我可以这样做：

NSMutableData *data = [NSMutableData dataWithLength:length];
int result = SecRandomCopyBytes(kSecRandomDefault, length, data.mutableBytes);

在Swift中尝试此操作时，我有以下内容：

let data = NSMutableData(length: Int(length))
let result = SecRandomCopyBytes(kSecRandomDefault, length, data.mutableBytes)

但是我得到了这个编译错误：

'Void' is not identical to 'UInt8'

data.mutableBytes参数被拒绝，因为类型不匹配，但我无法弄清楚如何强制参数（我假设它在某种程度上是安全的）。

Answer 1

这似乎有效：

let data = NSMutableData(length: Int(length))
let result = SecRandomCopyBytes(kSecRandomDefault, length, UnsafeMutablePointer<UInt8>(data.mutableBytes))

Answer 2

Swift 5

var data = Data(count: <count>)
let result = data.withUnsafeMutableBytes {    
    SecRandomCopyBytes(kSecRandomDefault, data.count, $0.baseAddress!) 
}

Swift 4 ：

var data = Data(count: <count>)
let result = data.withUnsafeMutableBytes { mutableBytes in
    SecRandomCopyBytes(kSecRandomDefault, data.count, mutableBytes)
}

Answer 3

Swift 4版本：

let count = 16
var data = Data(count: count)
_ = data.withUnsafeMutableBytes {
    SecRandomCopyBytes(kSecRandomDefault, count, $0)
}

Swift语言：如何调用SecRandomCopyBytes

3 个答案: