Replace hand-rolled arraycopy with stdlib copyInto

Author: LouisCAD

kotlinx-coroutines-core/common/src/channels/ConflatedBroadcastChannel.kt

@@ -145,8 +145,15 @@ public class ConflatedBroadcastChannel<E>() : BroadcastChannel<E> {
         check(i >= 0)
         if (n == 1) return null
         val update = arrayOfNulls<Subscriber<E>>(n - 1)
-        arraycopy(list, 0, update, 0, i)
-        arraycopy(list, i + 1, update, i, n - i - 1)
+        list.copyInto(
+            destination = update,
+            endIndex = i
+        )
+        list.copyInto(
+            destination = update,
+            destinationOffset = i,
+            startIndex = i + 1
+        )
         return update as Array<Subscriber<E>>
     }
 

kotlinx-coroutines-core/common/src/internal/ArrayCopy.common.kt

@@ -36,9 +36,15 @@ internal open class ArrayQueue<T : Any> {
         val currentSize = elements.size
         val newCapacity = currentSize shl 1
         val newElements = arrayOfNulls<Any>(newCapacity)
-        val remaining = elements.size - head
-        arraycopy(elements, head, newElements, 0, remaining)
-        arraycopy(elements, 0, newElements, remaining, head)
+        elements.copyInto(
+            destination = newElements,
+            startIndex = head
+        )
+        elements.copyInto(
+            destination = newElements,
+            destinationOffset = elements.size - head,
+            endIndex = head
+        )
         elements = newElements
         head = 0
         tail = currentSize

kotlinx-coroutines-core/common/src/internal/ArrayQueue.kt

@@ -4,7 +4,6 @@
 
 package kotlinx.coroutines
 
-import kotlinx.coroutines.internal.*
 import kotlin.coroutines.*
 import kotlin.native.concurrent.*
 
@@ -55,9 +54,15 @@ private class ArrayStack {
         val currentSize = elements.size
         val newCapacity = currentSize shl 1
         val newElements = arrayOfNulls<String>(newCapacity)
-        val remaining = elements.size - head
-        arraycopy(elements, head, newElements, 0, remaining)
-        arraycopy(elements, 0, newElements, remaining, head)
+        elements.copyInto(
+            destination = newElements,
+            startIndex = head
+        )
+        elements.copyInto(
+            destination = newElements,
+            destinationOffset = elements.size - head,
+            endIndex = head
+        )
         elements = newElements
     }
 }

kotlinx-coroutines-core/common/test/flow/NamedDispatchers.kt

@@ -21,9 +21,17 @@ internal class CopyOnWriteList<E>(private var array: Array<Any?> = arrayOfNulls(
     override fun add(index: Int, element: E) {
         rangeCheck(index)
         val update = arrayOfNulls<Any?>(if (array.size == _size) array.size * 2 else array.size)
-        arraycopy(array, 0, update, 0, index)
+        array.copyInto(
+            destination = update,
+            endIndex = index
+        )
         update[index] = element
-        arraycopy(array, index, update, index + 1, _size - index + 1)
+        array.copyInto(
+            destination = update,
+            destinationOffset = index + 1,
+            startIndex = index,
+            endIndex = _size + 1
+        )
         array = update
     }
 
@@ -43,8 +51,16 @@ internal class CopyOnWriteList<E>(private var array: Array<Any?> = arrayOfNulls(
         val n = array.size
         val element = array[index]
         val update = arrayOfNulls<Any>(n)
-        arraycopy(array, 0, update, 0, index)
-        arraycopy(array, index + 1, update, index, n - index - 1)
+        array.copyInto(
+            destination = update,
+            endIndex = index
+        )
+        array.copyInto(
+            destination = update,
+            destinationOffset = index,
+            startIndex = index + 1,
+            endIndex = n
+        )
         array = update
         --_size
         return element as E