Add static access to JNI GetDirectBufferAddress

src/main/java/org/bytedeco/javacpp/Pointer.java

@@ -33,6 +33,7 @@
 import java.util.Iterator;
 import java.util.concurrent.atomic.AtomicInteger;
 import org.bytedeco.javacpp.annotation.Name;
+import org.bytedeco.javacpp.annotation.Raw;
 import org.bytedeco.javacpp.tools.Generator;
 import org.bytedeco.javacpp.tools.Logger;
 
@@ -589,6 +590,10 @@ public static long maxPhysicalBytes() {
     /** Returns the amount of physical memory that is free according to the operating system, or 0 if unknown. */
     @Name("JavaCPP_availablePhysicalBytes") public static native long availablePhysicalBytes();
 
+    /** Returns the starting address of the memory region referenced by the given direct {@link java.nio.Buffer}.
+     * An alternative to allocating a new Pointer object if all you need is the memory address. */
+    @Name("JavaCPP_getDirectBufferAddress") protected static native long getDirectBufferAddress(@Raw(withEnv = true) Buffer b);
+
     /** The native address of this Pointer, which can be an array. */
     protected long address = 0;
     /** The index of the element of a native array that should be accessed. */

src/main/java/org/bytedeco/javacpp/tools/Generator.java

@@ -888,6 +888,10 @@ boolean classes(boolean handleExceptions, boolean defineAdapters, boolean conver
             out.println("    env->DeleteGlobalRef(globalRef);");
             out.println("}");
             out.println();
+            out.println("static inline jlong JavaCPP_getDirectBufferAddress(JNIEnv *env, jclass cls, jobject obj) {");
+            out.println("    return (jlong)env->GetDirectBufferAddress(obj);");
+            out.println("}");
+            out.println();
         }
         out.println("static JavaCPP_noinline jclass JavaCPP_getClass(JNIEnv* env, int i) {");
         out.println("    if (JavaCPP_classes[i] == NULL && env->PushLocalFrame(1) == 0) {");

src/test/java/org/bytedeco/javacpp/BufferTest.java

@@ -101,6 +101,7 @@ public ByteBuffer call(ByteBuffer buffer) {
         BytePointer pointer = new BytePointer(arrayBuffer);
         ByteBuffer directBuffer = pointer.asBuffer();
         assertEquals(pointer.address(), new BytePointer(directBuffer).address());
+        assertEquals(pointer.address(), Pointer.getDirectBufferAddress(directBuffer));
 
         assertTrue(directBuffer.compareTo(arrayBuffer) == 0);
         assertEquals(arrayBuffer.position(), directBuffer.position());
@@ -123,6 +124,7 @@ public ByteBuffer call(ByteBuffer buffer) {
         ShortPointer pointer = new ShortPointer(arrayBuffer);
         ShortBuffer directBuffer = pointer.asBuffer();
         assertEquals(pointer.address() + pointer.position() * pointer.sizeof(), new ShortPointer(directBuffer).address());
+        assertEquals(pointer.address() + pointer.position() * pointer.sizeof(), Pointer.getDirectBufferAddress(directBuffer));
 
         assertTrue(directBuffer.compareTo(arrayBuffer) == 0);
         assertEquals(arrayBuffer.limit() - arrayBuffer.position(), directBuffer.limit());
@@ -144,6 +146,7 @@ public ByteBuffer call(ByteBuffer buffer) {
         IntPointer pointer = new IntPointer(arrayBuffer);
         IntBuffer directBuffer = pointer.asBuffer();
         assertEquals(pointer.address() + pointer.position() * pointer.sizeof(), new IntPointer(directBuffer).address());
+        assertEquals(pointer.address() + pointer.position() * pointer.sizeof(), Pointer.getDirectBufferAddress(directBuffer));
 
         assertTrue(directBuffer.compareTo(arrayBuffer) == 0);
         assertEquals(arrayBuffer.limit() - arrayBuffer.position(), directBuffer.limit());
@@ -165,6 +168,7 @@ public ByteBuffer call(ByteBuffer buffer) {
         LongPointer pointer = new LongPointer(arrayBuffer);
         LongBuffer directBuffer = pointer.asBuffer();
         assertEquals(pointer.address() + pointer.position() * pointer.sizeof(), new LongPointer(directBuffer).address());
+        assertEquals(pointer.address() + pointer.position() * pointer.sizeof(), Pointer.getDirectBufferAddress(directBuffer));
 
         assertTrue(directBuffer.compareTo(arrayBuffer) == 0);
         assertEquals(arrayBuffer.limit() - arrayBuffer.position(), directBuffer.limit());
@@ -186,6 +190,7 @@ public ByteBuffer call(ByteBuffer buffer) {
         FloatPointer pointer = new FloatPointer(arrayBuffer);
         FloatBuffer directBuffer = pointer.asBuffer();
         assertEquals(pointer.address() + pointer.position() * pointer.sizeof(), new FloatPointer(directBuffer).address());
+        assertEquals(pointer.address() + pointer.position() * pointer.sizeof(), Pointer.getDirectBufferAddress(directBuffer));
 
         assertTrue(directBuffer.compareTo(arrayBuffer) == 0);
         assertEquals(arrayBuffer.limit() - arrayBuffer.position(), directBuffer.limit());
@@ -207,6 +212,7 @@ public ByteBuffer call(ByteBuffer buffer) {
         DoublePointer pointer = new DoublePointer(arrayBuffer);
         DoubleBuffer directBuffer = pointer.asBuffer();
         assertEquals(pointer.address() + pointer.position() * pointer.sizeof(), new DoublePointer(directBuffer).address());
+        assertEquals(pointer.address() + pointer.position() * pointer.sizeof(), Pointer.getDirectBufferAddress(directBuffer));
 
         assertTrue(directBuffer.compareTo(arrayBuffer) == 0);
         assertEquals(arrayBuffer.limit() - arrayBuffer.position(), directBuffer.limit());