Swift - 从 UnsafePointer<UInt8> 转换长度为字符串 [英] Swift - converting from UnsafePointer&lt;UInt8&gt; with length to String

问题描述

我考虑了很多类似的问题，但仍然无法让编译器接受这一点.

I considered a lot of similar questions, but still can't get the compiler to accept this.

Socket Mobile API(在 Objective-C 中)将 ISktScanDecodedData 传递给 Swift 中的委托方法(数据可能是二进制的，我想这就是它不作为字符串提供的原因):

Socket Mobile API (in Objective-C) passes ISktScanDecodedData into a delegate method in Swift (the data may be binary, which I suppose is why it's not provided as string):

func onDecodedData(device: DeviceInfo?, DecodedData d: ISktScanDecodedData?) {
  let symbology: String = d!.Name()
  let rawData: UnsafePointer<UInt8> = d!.getData()
  let rawDataSize: UInt32 = decoded!.getDataSize()
  // want a String (UTF8 is OK) or Swifty byte array...
}

在 C# 中，此代码将原始数据转换为字符串:

In C#, this code converts the raw data into a string:

string s = Marshal.PtrToStringAuto(d.GetData(), d.GetDataSize());

在 Swift 中，我可以达到 UnsafeArray，但后来我卡住了:

In Swift, I can get as far as UnsafeArray, but then I'm stuck:

let rawArray = UnsafeArray<UInt8>(start: rawData, length: Int(rawDataSize))

或者我看到 String.fromCString 和 NSString.stringWithCharacters，但它们都不会接受手头的参数类型.例如，如果我可以从 UnsafePointer 转换为 UnsafePointer<()>，那么这将是可用的(尽管我不确定它是否甚至会注意安全):

Alternatively I see String.fromCString and NSString.stringWithCharacters, but neither will accept the types of arguments at hand. If I could convert from UnsafePointer<UInt8> to UnsafePointer<()>, for example, then this would be available (though I'm not sure if it would even be safe):

NSData(bytesNoCopy: UnsafePointer<()>, length: Int, freeWhenDone: Bool)

有没有明显的方法可以从这一切中取出一个字符串?

Is there an obvious way to get a string out of all this?

推荐答案

这应该有效:

let data = NSData(bytes: rawData, length: Int(rawDataSize))
let str = String(data: data, encoding: NSUTF8StringEncoding)

Swift 3 更新:

let data = Data(bytes: rawData, count: Int(rawDataSize))
let str = String(data: data, encoding: String.Encoding.utf8)

结果字符串为 nil 如果数据不代表一个有效的 UTF-8 序列.

The resulting string is nil if the data does not represent a valid UTF-8 sequence.

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