Difficulty with Interop of Array of Pointers

Native
1

Hello,

I have an API I’d like to use with the following declaration:

typealias PLFLT = Double
typealias PLFLTVar = DoubleVarOf<PLFLT>
typealias PLFLT_VECTOR = CPointer<PLFLTVar>
fun c_plline(n: PLINT, x: PLFLT_VECTOR?, y: PLFLT_VECTOR?)

I’m trying to call this function like this:

val Array<Point>.x get() = map { p -> p.x }
val Array<Point>.y get() = map { p -> p.y }

fun line(points: List<Point>)
{
    memScoped {
        val bufferX = allocArray<PLFLT>(points.size)
        val bufferY = allocArray<PLFLT>(points.size)
        points.x.forEachIndexed { index, value -> bufferX[index] = value }
        points.y.forEachIndexed { index, value -> bufferY[index] = value }
        c_plline(points.size, bufferX, bufferY)
    }
}

That doesn’t work because:

  • the pointer doesn’t accept the operator;
  • allocArray() returns a CArrayPointer; not a CPointer

I have also tried to use cValuesOf() unsuccessfully.

Not sure how to do it properly. I’d appreciate any suggestions.

2

Never mind. The problem had nothing to do with the interop. It was the Array property extension that had to be List. And PLFLT had to be PLFLTVar.

3

Btw, CArrayPointer is just a typealias fro CPointer.

https://github.com/JetBrains/kotlin-native/blob/master/Interop/Runtime/src/main/kotlin/kotlinx/cinterop/Types.kt#L457