SWIG - byte array as IN parameter

Question

Hello J-Programmers!
It is about native calls.
I have a remaining problem for weeks.
SWIG is used to generate JNI code so as to build a Java interface of a home-made native library.
The goal is to "pass a byte[ ] from Java to C as an input parameter".
The problem is that SWIG keeps seeing it as an inout parameter and I can't managed to tune that.
Of course the program is working but clearly there is a useless back copy (see *)...
Here is the code result:
-- .h file
%include "typemaps.i"
%include "arrays_java.i"
UFIP_API bool VComWriteLoc (VCOMREF v, signed char buffer[], int size);
-- java module class
public static boolean VComWriteLoc(int v, byte[] buffer, int size)
-- wrap code
JNIEXPORT jboolean JNICALL Java_hep_fip_driver_FipUserLibJNI_VComWriteLoc(JNIEnv *jenv, jclass jcls, jint jarg1, jbyteArray jarg2, jint jarg3) {
jboolean jresult = 0 ;
int arg1 ;
signed char *arg2 ;
int arg3 ;
bool result;
jbyte *jarr2 ;
(void)jenv;
(void)jcls;
arg1 = (int)jarg1;
if (!SWIG_JavaArrayInSchar(jenv, &jarr2, &arg2, jarg2)) return 0;
arg3 = (int)jarg3;
result = (bool)VComWriteLoc(arg1,arg2,arg3);
jresult = (jboolean)result;
SWIG_JavaArrayArgoutSchar(jenv, jarr2, arg2, jarg2); // <--- useless back copy (*)
free(arg2);
return jresult;
Any idea?
Thanks in advance.
g2

Answer 1

re-Hello World!
Just some information about SWIG questions (SWIG-Java issues inclusive).
An active mailing list can be found directly from the SWIG site: www.swig.org :)
g2