SharedBuffer between Java and C++ using JNI

Question

what I am working on is to read image data from camera using C++ and use JNI to let Java read those image data, and I am using Mac OSX.

The blocker I currently have is, I have not found any method to create a shared memory between two language on Mac OSX.

I could imagine I will be using some buffer to do so, could anyone gives some hints and knowledge towards this problem?

Thank you in advance!

Answer 1

You can use ByteBuffer.allocateDirect to create native accessible memory:

public static native void getCameraData(ByteBuffer bb);

...

ByteBuffer bb = ByteBuffer.allocateDirect(1024);
getCameraData(bb);
// use data

Then on the C++ side, use GetDirectBufferAddress, to access the block of memory:

JNIEXPORT void JNICALL Java_MyClass_getCameraData(JNIEnv *env, jclass, jobject bb) {
    void* data = env->GetDirectBufferAddress(bb);
}