Deallocation of handle 'hIsmRendererData'

The following code that deallocates handle hIsmRendererData is repeated five times in the code:

    if ( st_ivas->hIsmRendererData != NULL )
    {
        if ( st_ivas->hIsmRendererData->interpolator != NULL )
        {
            free( st_ivas->hIsmRendererData->interpolator );
            st_ivas->hIsmRendererData->interpolator = NULL;
        }

        free( st_ivas->hIsmRendererData );
        st_ivas->hIsmRendererData = NULL;
    }

It could be replaced by a new function called from all five places.