Re: [Swig-user] Performance issue

[William S F. <ws...@fu...>]

prince0 wrote:
> Hi,
> 
> How can I request swig to declare local variables on the same line then 
> when necessary?
> 
> I tried “–small” command line option but it doesn’t work like I expect.
> 
>  
> 
> e.g. swig generates the following C++ wrapper:
> 
>  
> 
> SWIGEXPORT void * SWIGSTDCALL CSharp_CBACnetDriver_GetCache(void * jarg1)  {
> 
>   void * jresult ;
> 
>   CBACnetDriver *arg1 = (CBACnetDriver *) 0 ;
> 
>   CCache result;
> 
>  
> 
>   arg1 = (CBACnetDriver *)jarg1;
> 
>   result = (arg1)->GetCache();
> 
>   jresult = new CCache((const CCache &)result);
> 
>   return jresult;
> 
> }
> 
>  
> 
> I would like it to generate the following code instead:
> 
>  
> 
> SWIGEXPORT void * SWIGSTDCALL CSharp_CBACnetDriver_GetCache(void * jarg1)  {
> 
>   CBACnetDriver *  arg1 = (CBACnetDriver *)jarg1;
> 
>   CCache result = (arg1)->GetCache();
> 
>   void * jresult = new CCache((const CCache &)result);
> 
>   return jresult;
> 
> }
> 
>  
> 
> This second code will go faster because the constructor of the CCache 
> class will be called only one.
> 
> Moreover it would work better since I won’t have memory leaks. The fact 
> is the constructor of my class CCache allocates memory via the new 
> operator but does not have a copy constructor.
> 
Read about the optimal attribute in the out typemap:
http://www.swig.org/Doc1.3/Typemaps.html#Typemaps_optimal
You might also want to look at the valuewrapper feature:
http://www.swig.org/Doc1.3/SWIGPlus.html#SWIGPlus_nn19

William