'init 不可用：使用 'withMemoryRebound(to:capacity:_)' 临时将内存视为另一种布局兼容类型

Question

自从我将我的代码转换为 Swift 3 后，出现了错误。

'init is unavailable: use 'withMemoryRebound(to:capacity:_)' to temporarily view memory as another layout-compatible type.

这是我的代码：

func parseHRMData(data : NSData!)
{
    var flags : UInt8
    var count : Int = 1
    var zw = [UInt8](count: 2, repeatedValue: 0)

    flags = bytes[0]
    /*----------------FLAGS----------------*/
        //Heart Rate Value Format Bit
        if([flags & 0x01] == [0 & 0x01])
        {
            //Data Format is set to UINT8
            //convert UINT8 to UINT16
            zw[0] = bytes[count]
            zw[1] = 0
            bpm = UnsafePointer<UInt16>(zw).memory

            print("HRMLatitude.parseData Puls(UINT8): \(bpm)BPM")

            //count field index
            count = count + 1
        }

我该如何解决这个错误？

提前致谢！

Answer 1

zw是UInt8的数组。重新解释指向元素的指针作为指向 UInt16、withMemoryRebound() 的指针的存储必须是打电话给 Swift 3. 在你的情况下：

var zw = [UInt8](repeating: 0, count: 2)
// Alternatively:
var zw: [UInt8] = [0, 0]

// ...

let bpm = UnsafePointer(zw).withMemoryRebound(to: UInt16.self, capacity: 1) {
    [=10=].pointee
}

另一种解决方案是

let bpm = zw.withUnsafeBytes {
    [=11=].load(fromByteOffset: 0, as: UInt16.self)
}

参见 SE-0107 UnsafeRawPointer API 有关原始指针、类型化指针和重新绑定的更多信息。

'init 不可用：使用 'withMemoryRebound(to:capacity:_)' 临时将内存视为另一种布局兼容类型

'init is unavailable: use 'withMemoryRebound(to:capacity:_)' to temporarily view memory as another layout-compatible type

swift

swift3

unsafe-pointers