Hi, how can I convert a Swift `NSData` to Kotlin `ByteArray`? Background: I’m working on a Kmp libra...

# multiplatform

[Bao Le Duc]

Hi, how can I convert a Swift NSData to Kotlin ByteArray?
Background: I’m working on a Kmp library where we need to use OS’s crypto API to encrypt data. So, in Kmp library we define an Interface

interface MessagePackHelper {
    fun serialize(payload: String): ByteArray
}

from iOS, we need to implement this interface and set back to the Kmp library. So in Swift, we need to implement below method:

func serialize(payload: String) -> KotlinByteArray {
        // let encyrpted = encrypt(payload) // result is NSData obect
        // todo - would like to convert NSData -> KotlinByteArray
    }

[Evegenii Khokhlov]

fun NSData.toByteArray(): ByteArray {
    return ByteArray(length.toInt()).apply {
        usePinned {
            memcpy(it.addressOf(0), bytes, length)
        }
    }
}

fun ByteArray.toNSData(): NSData = memScoped { 
    NSData.create(bytes = allocArrayOf(this@toNSData), length = [e-mail]()) 
}

[Bao Le Duc]

Thanks @Evegenii Khokhlov. That should be Kotlin code defined in iOS source set, isn’t it?

[Evegenii Khokhlov]

Yes, you are right, you need to import platform.Foundation.*

[Evegenii Khokhlov]

and also import platform.posix.memcpy

[Bao Le Duc]

Great, I will try it out