Java21-specific code

Author: Chessray

src/main/java21/com/evolvedbinary/jnibench/jmhbench/cache/MemorySegmentCache.java

@@ -0,0 +1,62 @@
+package com.evolvedbinary.jnibench.jmhbench.cache;
+
+import static java.lang.foreign.ValueLayout.JAVA_BYTE;
+
+import java.lang.foreign.Arena;
+import java.lang.foreign.MemorySegment;
+import java.lang.foreign.ValueLayout;
+import java.util.stream.IntStream;
+
+public class MemorySegmentCache extends LinkedListAllocationCache<MemorySegment> {
+  private final Arena arena;
+
+  public MemorySegmentCache() {
+    arena = Arena.ofShared();
+  }
+
+
+  @Override
+  MemorySegment allocate(final int valueSize) {
+    return arena.allocate(valueSize);
+  }
+
+  @Override
+  void free(final MemorySegment buffer) {
+    // Nothing to do here, as we override taerdown() directly.
+  }
+
+  @Override
+  public void tearDown() {
+    super.tearDown();
+    arena.close();
+  }
+
+  @Override
+  protected int byteChecksum(final MemorySegment item) {
+    return IntStream.range(0, (int) item.byteSize()).map(offset -> item.get(JAVA_BYTE, offset)).sum();
+  }
+
+  @Override
+  protected int longChecksum(final MemorySegment item) {
+    return byteChecksum(item);
+  }
+
+  @Override
+  protected byte[] copyOut(final MemorySegment item) {
+    // Get a cached byte array of the correct size
+    byte[] array = byteArrayOfSize((int) item.byteSize());
+
+    // Perform bulk copy from native memory to Java heap array
+    MemorySegment.copy(item, ValueLayout.JAVA_BYTE, 0, array, 0, (int) item.byteSize());
+
+    return array;
+  }
+
+  @Override
+  protected long copyIn(final MemorySegment item, final byte fillByte) {
+    // Highly optimized bulk fill (native memset equivalent)
+    item.fill(fillByte);
+
+    return fillByte;
+  }
+}