Swift: Convert structs and enums to NSData and vice-versa

func encode<T>(var value: T) -> NSData {
    return withUnsafePointer(&value) { p in
        NSData(bytes: p, length: sizeofValue(value))
    }
}

func decode<T>(data: NSData) -> T {
    let pointer = UnsafeMutablePointer<T>.alloc(sizeof(T.Type))
    data.getBytes(pointer)
    
    return pointer.move()
}

// Example:
enum Result<T> {
    case Success(T)
    case Failure
}

var res: Result<String> = .Success("yeah")

var data = encode(res)

var decoded: Result<String> = decode(data)

switch decoded {
case .Failure:
    "failure"
case .Success(let v):
    "success: \(v)" // => "success: yeah"
}

It seems to fail sometimes, returns nil once in a while even without changing anything on the struct

@RollingGoron speed