Re: [Swig-user] What is the proper way to pass a binary arrays with numerous "\0" from c++ to python?

[Stefan Z. <sz...@gm...>]

On Fri, Jul 29, 2011 at 8:47 PM, Joe Chan <fre...@gm...> wrote:

> I want to use a c++ program to read a jpg then pass it to python.
>
> however since jpg has numerous '\0' inside. Python always think that the
> jpg only contains less than 10 bytes.
>
> My question is what is the proper way to pass a binary arrays with numerous
> "\0" from c++ to python.
>

Assuming you don't want to actually manipulate the jpeg data in python, but
simply want to pass it around as an opaque object, you can write a set of
typemaps that use the PyCapsule API, something like this:

%typemap(out) char * {
  $result = PyCapsule_New((void*) $1, NULL, NULL);
}

%typemap(in) char * {
  $1 = (char*) PyCapsule_GetPointer($input, NULL);
}

As written, these typemaps will apply to all methods that take/return char*;
you'll need to apply them selectively if you have other methods that use
char* as a string.

Hope that helps.

Stefan


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