feat: Add read/write for fixed-sized arrays (#191)

Fixes #181

Author: markehammons

build.sc

@@ -13,7 +13,7 @@ import mill.contrib.scoverage.{ScoverageModule, ScoverageReport}
 object scoverage extends BaseModule with ScoverageReport
 
 trait BaseModule extends ScoverageModule with ScalafmtModule {
-  def scalaVersion = "3.3.0-RC5"
+  def scalaVersion = "3.3.0-RC6"
   def scoverageVersion = "2.0.7"
 
   val munitVersion = "1.0.0-M7"

core/src/fr/hammons/slinc/DescriptorOf.scala

@@ -4,6 +4,7 @@ import fr.hammons.slinc.container.*
 import scala.quoted.*
 import scala.compiletime.{summonInline, erasedValue, constValue}
 import scala.NonEmptyTuple
+import scala.reflect.ClassTag
 
 /** Typeclass that summons TypeDescriptors
   */
@@ -78,8 +79,8 @@ object DescriptorOf:
         CUnionDescriptor(helper[A])
           .asInstanceOf[CUnionDescriptor { type Inner = CUnion[A] }]
 
-  inline given [A, B <: Int](using
-      innerDesc: DescriptorOf[A]
+  inline given [A, B <: Int](using innerDesc: DescriptorOf[A])(using
+      classTag: ClassTag[innerDesc.descriptor.Inner]
   ): DescriptorOf[SetSizeArray[A, B]] = new DescriptorOf[SetSizeArray[A, B]]:
     val descriptor: TypeDescriptor { type Inner = SetSizeArray[A, B] } =
       SetSizeArrayDescriptor(innerDesc.descriptor, constValue[B]).asInstanceOf[

core/src/fr/hammons/slinc/SetSizeArray.scala

@@ -5,7 +5,6 @@ import scala.compiletime.ops.int.{`*`, `-`, `<=`, `+`, `<`}
 import scala.compiletime.constValue
 import scala.quoted.*
 import scala.language.experimental.erasedDefinitions
-import scala.annotation.experimental
 
 class SetSizeArray[A, B <: Int] private[slinc] (private val array: Array[A])
     extends AnyVal:
@@ -16,6 +15,7 @@ class SetSizeArray[A, B <: Int] private[slinc] (private val array: Array[A])
   ): SetSizeArray[C, B * D] =
     new SetSizeArray[C, B * D](array.flatMap(fn.andThen(_.array)))
   def toSeq: Seq[A] = array.toSeq
+  def toArray: Array[A] = array
   inline def take[C <: Int](using
       C <= B =:= true,
       0 <= C =:= true

core/src/fr/hammons/slinc/TypeDescriptor.scala

@@ -14,12 +14,14 @@ import fr.hammons.slinc.modules.TransitionModule
 import fr.hammons.slinc.modules.{ArgumentTransition, ReturnTransition}
 import scala.NonEmptyTuple
 import scala.language.implicitConversions
-import dotty.tools.dotc.transform.patmat.Typ
 
 /** Describes types used by C interop
   */
 sealed trait TypeDescriptor:
+  self =>
   type Inner
+  given DescriptorOf[Inner] with
+    val descriptor = self
   def size(using dm: DescriptorModule): Bytes = dm.sizeOf(this)
   def alignment(using dm: DescriptorModule): Bytes = dm.alignmentOf(this)
   def toCarrierType(using dm: DescriptorModule): Class[?] =
@@ -220,13 +222,19 @@ case class CUnionDescriptor(possibleTypes: Set[TypeDescriptor])
 case class SetSizeArrayDescriptor(
     val contained: TypeDescriptor,
     val number: Int
-) extends TypeDescriptor:
+)(using ClassTag[contained.Inner])
+    extends TypeDescriptor:
 
   override val reader: (ReadWriteModule, DescriptorModule) ?=> Reader[Inner] =
-    ???
+    (mem, offset) =>
+      new SetSizeArray(
+        summon[ReadWriteModule].readArray[contained.Inner](mem, offset, number)
+      )
 
   override val writer: (ReadWriteModule, DescriptorModule) ?=> Writer[Inner] =
-    ???
+    (mem, offset, value) =>
+      summon[ReadWriteModule]
+        .writeArray[contained.Inner](mem, offset, value.toArray)
 
   override val argumentTransition
       : (TransitionModule, ReadWriteModule, Allocator) ?=> ArgumentTransition[
@@ -236,4 +244,4 @@ case class SetSizeArrayDescriptor(
   override val returnTransition
       : (TransitionModule, ReadWriteModule) ?=> ReturnTransition[Inner] = ???
 
-  type Inner = SetSizeArray[?, ?]
+  type Inner = SetSizeArray[contained.Inner, ?]

core/test/src/fr/hammons/slinc/TransferSpec.scala

@@ -28,6 +28,8 @@ trait TransferSpec[ThreadException <: Throwable](val slinc: Slinc)(using
 
   case class F(u: CUnion[(CInt, CFloat)]) derives Struct
 
+  case class G(arr: SetSizeArray[CLong, 2]) derives Struct
+
   test("can read and write jvm ints") {
     Scope.global {
       val mem = Ptr.blank[Int]
@@ -353,3 +355,27 @@ trait TransferSpec[ThreadException <: Throwable](val slinc: Slinc)(using
           }
 
           assertEquals(fReturn.u.get[CFloat], union.get[CFloat])
+
+  test("can copy SetSizeArray[Int, 2] to native memory"):
+      val ssa = SetSizeArray(1, 2)
+
+      Scope.confined {
+        val ptr = Ptr.copy(ssa)
+        assertEquals((!ptr)[0], 1)
+      }
+
+  test("can copy SetSizeArray[CLong, 2] to native memory"):
+      val ssa = SetSizeArray(CLong(1), CLong(2))
+
+      Scope.confined {
+        val ptr = Ptr.copy(ssa)
+        assertEquals((!ptr)[0], CLong(1))
+      }
+
+  test("can copy G to native memory and back"):
+      val g = G(SetSizeArray(CLong(1), CLong(2)))
+
+      Scope.confined {
+        val ptr = Ptr.copy(g)
+        assertEquals((!ptr).arr[0], CLong(1))
+      }