ios - Swift 3 编译器错误 : 'bytes' is unavailable: use withUnsafeBytes instead

Question

我在 Swift 2.2 中有一个加密方法。如何从 Swift 3 中的数据中获取字节？

这是我的代码:

func myEncrypt(encryptData:String) -> String? {

    //security key must be 24charachters 
    let myKeyData : Data = "*******".data(using: String.Encoding.utf8)!
    let myRawData : Data = encryptData.data(using: String.Encoding.utf8)!
    let mykeydatamd5 = Data(bytes: myKeyData.bytes, count: 24)
    let Crypto_status: CCCryptorStatus = CCCrypt(operation, algoritm, options, mykeydatamd5.bytes   , keyLength, nil, myRawData.bytes, myRawData.count, buffer, buffer_size, &num_bytes_encrypted)

    if UInt32(Crypto_status) == UInt32(kCCSuccess){

        let myResult: Data = Data(bytes: buffer, count: num_bytes_encrypted)        
        free(buffer)

        return myResult.base64EncodedString()

    }else{

        free(buffer)        
        return nil

    }       
}

错误发生在myKeyData.bytes和myRawData.bytes中。

Answer 1

如错误信息所示，您需要改用withUnsafeBytes。

一般来说，如果你有这样的表达方式:

let result = someFunc(..., data.bytes, ...)

您需要将其重写为:

let result = data.withUnsafeBytes {dataBytes in
    someFunc(..., dataBytes, ...)
}

如果您在单个表达式中使用多个.bytes，您可能需要使用嵌套的withUnsafeBytes。在您的情况下，您的代码的相关部分应该是这样的:

let mykeydatamd5 = myKeyData.subdata(in: 0..<24)    //Assuming myKeyData.count >= 24

let crypto_status: CCCryptorStatus = mykeydatamd5.withUnsafeBytes {mykeydataBytes in
    myRawData.withUnsafeBytes {myRawDataBytes in
         CCCrypt(operation, algoritm, options, mykeydataBytes, keyLength, nil, myRawDataBytes, myRawData.count, buffer, buffer_size, &num_bytes_encrypted)
    }
}