Me again :-)
Ok, I've implemented heap Buffer arguments in V3. You can also do this
via a TypeMapper + ToNativeConverter.
That would be great. With this implemented, I think all the bases are
covered, namely:
- byte[] (VM pins or copies to give us a pointer)
- heap ByteBuffer (since ByteBuffer#array returns a byte[] which the VM
can pin or copy)
- direct ByteBuffer (pointer is available via a JNI call)
- float[] (VM pins or copies to give us a pointer)
- heap FloatBuffer (since FloatBuffer#array returns a float[] which the
VM can pin or copy)
- direct FloatBuffer (pointer is available via a JNI call)
AFAIK, there is no way to create nor access the pointer on a direct
FloatBuffer.
AFAIK, once you have the direct FloatBuffer as a jobject in your native
code, you can simply call GetDirectBufferAddress, just like you can on a
direct ByteBuffer.
According to the javadoc, the only way they are created is via
asFloatBuffer() on a direct ByteBuffer - and I couldn't see anyway to get
back to the direct ByteBuffer from a FloatBuffer view.
That means something like this will throw an exception:
FloatBuffer fb = ByteBuffer.allocateDirect(1024).asFloatBuffer();
some_function(fb);
Its a pretty weird corner case, and there's nothing JNA can do about it.
I'm not 100% sure if this will work, but as I mentioned in my previous mail,
if you pass any Buffer for which isDirect returns through to JNI, you should
be able to get its pointer.
Cheers,
Albert
12 messages in net.java.dev.jna.usersRe: [jna-users] Buffer arguments as p...
