Swift 3 不安全指针不明确的初始化和字节

Question

在尝试升级涉及将文件导出到 Swift 3 的库时，我遇到了两个主要问题。我已阅读 apple/swift migration page，但仍然不确定要确保我不这样做的最佳方法是什么丢失任何这些字节。很多例子都是转换字符串，但我实际上需要字节。

我遇到的第一个问题是在下面以stream.write 开头的每一行中，UnsafePointer<UIntX>(&var) 返回一个错误说Ambigious use of init。

var xbuffer = [UInt8](repeating: 0, count: 2048 + 171*1024)
let stream : OutputStream = OutputStream(toBuffer: &xbuffer, capacity: 2048 + 171*1024);
stream.open();

//Version number (2 bytes)
stream.write(Data(bytes: UnsafePointer<UInt8>(&(self.version)), count: 1).bytes.bindMemory(to: UInt8.self, capacity: Data(bytes: UnsafePointer<UInt8>(&(self.version)), count: 1).count),maxLength: 1);

stream.write(Data(bytes: UnsafePointer<UInt8>(&(self.subVersion)), count: 1).bytes.bindMemory(to: UInt8.self, capacity: Data(bytes: UnsafePointer<UInt8>(&(self.subVersion)), count: 1).count),maxLength: 1);

//Operation ID status code (2 bytes)
var opId_big = CFSwapInt16HostToBig(self.operationId);
stream.write(Data(bytes: UnsafePointer<UInt8>(&(opId_big)), count: 2).bytes.bindMemory(to: UInt8.self, capacity: Data(bytes: UnsafePointer<UInt8>(&(opId_big)), count: 2).count),maxLength: 2);

//Request ID (4 bytes)
requestId = requestId | 0x1;
var rqid_big = CFSwapInt32HostToBig(requestId);
stream.write(Data(bytes: UnsafePointer<UInt8>(&(rqid_big)), count: 4).bytes.bindMemory(to: UInt8.self, capacity: Data(bytes: UnsafePointer<UInt8>(&(rqid_big)), count: 4).count), maxLength: 4);

在创建Data 时，我可以通过对UnsafeRawPointer 和UnsafeBufferPointer 进行更改来更改此设置。

在我这样做之后，我遇到了另一个问题，Xcode 将打印bytes is unavailable use withUnsafeBytes instead 的错误。

总的来说，我可以使用这样的东西逐个修复次要部分，但是由于所有链式命令，我在进行多项更改和尝试 stackoverflow 解决方案和快速迁移实践时遇到了麻烦，因为需要进行多项更改链式命令。

我感谢任何答案或启示/方向。

Other Migration Page That Was Helpful

StackOverFlow Reference 1

Answer 1

一般情况下，您无需创建中间Data 即可将字节序列写入OutputStream。

    var xbuffer = [UInt8](repeating: 0, count: 2048 + 171*1024)
    xbuffer.withUnsafeMutableBufferPointer{bufferPointer in
        let stream : OutputStream = OutputStream(toBuffer: bufferPointer.baseAddress!, capacity: xbuffer.count);
        stream.open();

        //Version number (2 bytes)
        withUnsafeBytes(of: &self.version) {
            stream.write($0.baseAddress!.assumingMemoryBound(to: UInt8.self), maxLength: 1)
        }

        withUnsafeBytes(of: &self.subVersion) {
            stream.write($0.baseAddress!.assumingMemoryBound(to: UInt8.self), maxLength: 1)
        }

        //Operation ID status code (2 bytes)
        var opId_big = self.operationId.bigEndian
        withUnsafeBytes(of: &opId_big) {
            stream.write($0.baseAddress!.assumingMemoryBound(to: UInt8.self), maxLength: 2)
        }

        //Request ID (4 bytes)
        var rqid_big = (requestId | 0x1).bigEndian;
        withUnsafeBytes(of: &rqid_big) {
            stream.write($0.baseAddress!.assumingMemoryBound(to: UInt8.self), maxLength: 4)
        }
    }