Most likely a stupid question :smile: I have a `NSData` and need to get the first two and the last ...

# kotlin-native

[Christian Würthenr]

Most likely a stupid question 😄 I have a NSData and need to get the first two and the last two bytes out of it…any clue how I can do that? Below gives me the first two, but I don’t see any way to offset the bytes pointer by length - 2 to get the last two

private fun NSData.isCompleteJpeg(): Boolean {
            val byteArray = ByteArray(2)
            byteArray.usePinned {
                memcpy(it.addressOf(0), bytes, 2)
            }

            ....
   }

[Christian Würthenr]

Haha 😄 Never mind. Stumbled over the solution myself. The trick is to use reinterpret to get a UByte pointer and the you can use the [] to get a certain index

val x = bytes!!.reinterpret<UByteVar>()
val s1 = x[0]
val s2 = x[1]
val e1 = x[length.toInt() - 2]
val e2 = x[length.toInt() - 1]

[natario1]

Pointers also have a plus() function that you can use to move the pointer by a certain number of elements. You'd still need to reinterpret first though

[Christian Würthenr]

Ahh. got to know! thanks!

[Christian Würthenr]

Working with C pointers in Kotlin is not my favourite though 😄