[Swig-user] Help! Data remains null

[Juanjo V. <jv...@cn...>]

Hello everyone,

I'm experimenting a problem with JNI code generated by SWIG. The problem
is not exactly with the code, but when running.

I'm trying to use a library developed by others. It's a pretty complex
library written in C++ and I'm using it from java. I don't know much
about the library internals, apart from what I learn looking here and
there

Basically I'm using a class called "Image". This class inherits another
one: "ImageBase", and contains, among other stuff, an array with the
pixels values of the image. That array is a template, so I tell SWIG to
instantiate an image for double data type:

%{
#include "../image.h"
%}
%include "../image.h"
%template (ImageDouble) Image<double>;

When I create the Image using a filename for it, it reads the image
properly. Even if I print the info after reading it (in the C++ side),
everything is fine. But if I try to access data after returning to java
environment, the array is null, image size is 0, and so on.

I tried all the stuff I found on the internet (mainly
www.swig.org/Doc1.3/Java.html) and nothing works.

Some months ago, I remember to had the same problem, I tried a lot of
stuff, and finally it worked with no significant changes. Maybe because
of any change in the C++ library. That's because I think the problem is
any structure, template or whatever that SWIG might be skipping.

I can provide more info if anybody can help me, but before annoy the
list with so many stuff I prefer to ask if anybody has experimented
anything similar or if there is any simple idea I forgot to check.

By the way, this simple code, neither works:

	String path = "path_to_mi_image";
        FileName fn = new FileName(path);
        System.out.println(" Reading: " + fn.getBaseName());

It crashes at:

C  [libstdc++.so.6+0x8e495]  _ZNSsC1ERKSs+0x15
C  [libXmippData.so+0x217bb5]  _ZNK8FileName11getBaseNameEv+0x45
C  [libXmippDataJava.so+0x307c4]
Java_xmipp_XmippDataJNI_FileName_1getBaseName+0x44
j
xmipp.XmippDataJNI.FileName_getBaseName(JLxmipp/FileName;)Ljava/lang/String;+0
j  xmipp.FileName.getBaseName()Ljava/lang/String;+5
...

Which is not very helpful.

Thanks for reading, I hope you can help me, because I'm really lost with
this issue =/

Sincerely,

-- 
Juanjo Vega (jv...@cn...)

Unidad de Biocomputación. Laboratorio B-13.
Centro Nacional de Biotecnología. CNB-CSIC.
C\ Darwin, 3. Campus de Cantoblanco.
Universidad Autónoma de Madrid.
28049, Madrid, Spain.

+34 91 585 4510

http://www.cnb.csic.es
http://www.biocomp.cnb.csic.es

"Las mejores almas son capaces de los mayores vicios como de las mayores
virtudes, y aquellos que caminan despacio por el camino recto pueden
llegar más lejos que los que corren pero se apartan de él." - Discurso
del Método, René Descartes.