How to convert a double into a byte array in swift?

Question

I know how to do it in java (see here), but I couldn\'t find a swift equivalent for java\'s ByteBuffer, and consequently its .putDouble(double value) method.

Basically,

Answer 1

Here's my updated version to the original solution.

/// input: array of bytes 
/// -> get pointer to byte array (UnsafeBufferPointer<[Byte]>)
/// -> access its base address
/// -> rebind memory to target type T (UnsafeMutablePointer)
/// -> extract and return the value of target type
func binarytotype  (_ value: [Byte], _: T.Type) -> T
{
    return value.withUnsafeBufferPointer {
        $0.baseAddress!
          .withMemoryRebound(to: T.self, capacity: 1) {
            $0.pointee
        }
    }
}

/// input type: value of type T
/// -> get pointer to value of T
/// -> rebind memory to the target type, which is a byte array
/// -> create array with a buffer pointer initialized with the     source pointer
/// -> return the resulted array
func typetobinary  (_ value: T) -> [Byte]
{
    var mv : T = value
    let s : Int = MemoryLayout.size
    return withUnsafePointer(to: &mv) {
        $0.withMemoryRebound(to: Byte.self, capacity: s) {
            Array(UnsafeBufferPointer(start: $0, count: s))
        }
    }
}

PS: Don't forget to replace Byte with UInt8.