zakgof / java-native-benchmark Goto Github PK

package com.zakgof.jnbenchmark.panama;

import java.lang.invoke.*;
import jdk.incubator.foreign.*;
import jdk.incubator.foreign.MemoryLayout.*;

import static jdk.incubator.foreign.CLinker.*;

public class PanamaBenchmark {

	static final MemoryLayout SYSTEMTIME = MemoryLayout.ofStruct(
			C_SHORT.withName("wYear"),
			C_SHORT.withName("wMonth"),
			C_SHORT.withName("wDayOfWeek"),
			C_SHORT.withName("wDay"),
			C_SHORT.withName("wHour"),
			C_SHORT.withName("wMinute"),
			C_SHORT.withName("wSecond"),
			C_SHORT.withName("wMilliseconds")
	);

	// var handle

	final static VarHandle wSecond = SYSTEMTIME.varHandle(short.class, PathElement.groupElement("wSecond"));

	// method handle

	final static MethodHandle GetSystemTime = CLinker.getInstance().downcallHandle(
		LibraryLookup.ofDefault().lookup("GetSystemTime").get(),
		MethodType.methodType(void.class, MemoryAddress.class),
		FunctionDescriptor.ofVoid(C_POINTER)
	);

	final MemorySegment systemtime_shared;

	public PanamaBenchmark() {
		this.systemtime_shared = MemorySegment.allocateNative(SYSTEMTIME);
	}

	public short all() {
		try (MemorySegment systemtime = MemorySegment.allocateNative(SYSTEMTIME)) {
			GetSystemTime.invokeExact(systemtime.address());
			return (short) wSecond.get(systemtime);
		} catch (Throwable ex) {
			throw new AssertionError(ex);
		}
	}

	public void callOnly() {
		try {
			GetSystemTime.invokeExact(systemtime_shared.address());
		} catch (Throwable ex) {
			throw new AssertionError(ex);
		}
	}
}