ios swift, How to convert 'object to nsdata'

Question

I want to define a c ++ structure as swift code and serialize and deserialize it to write to socket.

class PacketHeader: NSObject, NSCoding {
    var ver: UInt8 = 0
    var len: UInt32 = 0

    required init(coder aDecoder: NSCoder) {
        ??
    }

    func encode(with aCoder: NSCoder) {
        ??
    }
}

I can not find a function to decode and encode uint8, uint32.

Answer 1

Xcode 8 (Swift 3) Playground:

class PacketHeader: NSObject, NSCoding {
    var ver: UInt8 = 0
    var len: UInt32 = 0

    override init() {
        super.init()
    }

    required init(coder aDecoder: NSCoder) {

        if let ver = aDecoder.decodeObject(forKey: "ver") as? NSNumber {
            self.ver = ver.uint8Value
        }

        if let len = aDecoder.decodeObject(forKey: "len") as? NSNumber {
            self.len = len.uint32Value
        }

    }

    func encode(with aCoder: NSCoder) {
        aCoder.encode(NSNumber(value: ver), forKey: "ver")
        aCoder.encode(NSNumber(value: len), forKey: "len")
    }

}

let data = PacketHeader()
data.ver = 10
data.len = 8

let savedData = NSKeyedArchiver.archivedData(withRootObject: data)
let obj = NSKeyedUnarchiver.unarchiveObject(with: savedData) as? PacketHeader
obj?.ver
obj?.len