Set a member of a C structure of type char * with Java byte array using SWIG

Question

For example we have the following structure:

typedef struct Foo
{
    unsigned char * data;
} Foo;

I want to set the data member with a Java byte array (byte[]). I only want set method not get. I've read the getting of a member of type char * to byte array, but I can't do the setting. Can anybody help me?

UPDATED:

I've created some type maps and I have a success:

%typemap(jni) unsigned char * data "jbyteArray"
%typemap(jtype) unsigned char * data "byte[]"
%typemap(jstype) unsigned char * data "byte[]"
%typemap(javaout) unsigned char * data {
    return $jnicall;
}
%typemap(out) signed char * data {
    $result = JCALL1(NewByteArray, jenv, arg1->contentLength);
    JCALL4(SetByteArrayRegion, jenv, $result, 0, arg1->contentLength, $1);
}
%typemap(in) unsigned char *data {
    $1 = (unsigned char *)JCALL2(GetByteArrayElements, jenv, $input, 0);
}
%typemap(javain) unsigned char *data "$javainput"

Do I have some memory leaks? Have I made it wrong or is there more reliable way?

You've not got anything calling RelaseByteArrayElements ever. I think you probably want to do something using memcpy to copy the contents. — Flexo - Save the data dump
– Flexo - Save the data dump ♦, Commented Nov 3, 2012 at 17:28

Samuel Audet · Accepted Answer · 2012-11-06 10:33:22Z

0

Or we could do it with JavaCPP instead. Something like this should work:

public static class Foo extends Pointer {
    static { Loader.load(); }
    public Foo() { allocate(); }
    public Foo(Pointer p) { super(p); }
    private native void allocate();

    public native @MemberSetter void data(@Cast("unsigned char*") BytePointer data);
}

That is IMO much more readable.

answered Nov 6, 2012 at 10:33

Samuel Audet

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