Re: union structures for 64 bit octave

[David Bateman]

Clinton Chee wrote:

> Hi All,
>
> In the process of checking some 64 bit octave code, I found the use of
> some union structures (see below). I've checked the code and don't think
> the int in these union structures need to be changed to octave_idx_type.
> Can someone confirm this?
>
>
> in src/unwind-prot.cc
>
>  union
>    {
>      bool *ptr_to_bool;
>      int *ptr_to_int;
>      void *gen_ptr;
>      void **ptr_to_gen_ptr;
>    };
>
>  union
>    {
>      bool bool_value;
>      int int_value;
>      const std::string *str_value;
>      void *gen_ptr_value;
>    };
>
>
>  
Does unwind_protect protect octave_idx_type variables? That is the real 
question. If so then the type index should be added to the enum var_type 
and the unions about should become

 union
   {
     bool *ptr_to_bool;
     int *ptr_to_int;
     octave_idx_type *ptr_to_index;
     void *gen_ptr;
     void **ptr_to_gen_ptr;
   };

 union
   {
     bool bool_value;
     int int_value;
     octave_idx_type index_value;
     const std::string *str_value;
     void *gen_ptr_value;
   };

You'd then need to add the function

saved_variable::saved_variable (octave_idx_type *p, int v)
{
 type_tag = index;
 ptr_to_index = p;
 index_value = v;
 size = sizeof (octave_idx_type);  // Is this necessary?
}

void
unwind_protect::save_index (octave_idx_type *ptr, octave_idx_type value)
{
 saved_variable *s = new saved_variable (ptr, value);
 add (saved_variable::restore, s);
}

and modify the function

void
saved_variable::restore_value (void)
{
 switch (type_tag)
   {
   case boolean:
     *ptr_to_bool = bool_value;
     break;

   case integer:
     *ptr_to_int = int_value;
     break;

   case index:
      *ptr_to_index = index_value;
       break;

which will allow you to protect octave_idx_type variable... Its probably 
worth doing this for later use, since its such to be needed eventually, 
even if it isn't needed now..

> in src/ov.h
>
>  union
>    {
>      octave_value *rep;      // The real representation.
>      int count;              // A reference count.
>    };
>
>  
You'd have to have 2^31 octave_value's all point to the same 
representation for count to need to be changed... I don't think is a 
problem..


> Thanks
> Clinton
>
>
>  


--
David Bateman                                address@hidden
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Parc Les Algorithmes, Commune de St Aubin    +33 1 69 35 77 01 (Fax) 
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