Re: some unsigned/NSInteger to NSUInteger changes in -gui

[Fred Kiefer]

Looks like you two will need another round to get David's explanations 
over. As this leaves the gui code broken for some time longer, I just 
committed David's fix.

Fred

On 10.04.2012 19:57, Sebastian Reitenbach wrote:
> On Tuesday, April 10, 2012 19:24 CEST, David Chisnall<address@hidden>  wrote:
>
> > On 10 Apr 2012, at 18:18, Sebastian Reitenbach wrote:
> >
> > > +       {
> > > +         int tmp = (int)_selected_item;
> > > +          [aDecoder decodeValueOfObjCType: @encode(int) at:&_selected_item];
> > > +          _selected = [_items objectAtIndex: tmp];
> > > +       }
> >
> > No, this is still wrong, and I'm not really sure what it's trying to do...
> >
> > Let's say you're on some big-endian LP64 system.  NSInteger will be a 64-bit 
> > integer while int will be a 32-bit integer.  You pass a pointer to the 
> > NSInteger to aDecoder, and tell it that it's a pointer to an int.  It will then 
> > cast this pointer and will write a 32-bit value into the first 32 bits of the 
> > ivar.  Unfortunately, because this is a big endian system, you've now set the 
> > value to something about four billion times as big as it should be...
> >
> > As I said in my last email, the correct form is:
> >
> >         int tmp;
> >         [aDecoder decodeValueOfObjCType: @encode(int) at:&tmp];
> >         _selected_item = tmp;
> >
> > This creates an int on the stack and passes a pointer to it to aDecoder, which 
> > then loads an int-sized value and stores it in the int.  You then assign this 
> > value to the ivar.  The implicit cast (you can make it explicit if you prefer) 
> > will extend this to the correct size.
>
> Thanks for your patience. Now I got it, the decoder already has the value, and 
> just puts it in, where the pointer points it to. But I still think I need to 
> assign
> _selected = [_items objectAtIndex: tmp];
>
> so that it will be right.
>
> Sebastian
>
> Index: NSTabView.m
> ===================================================================
> --- NSTabView.m (revision 35052)
> +++ NSTabView.m (working copy)
> @@ -52,7 +52,7 @@
>   {
>     if (self == [NSTabView class])
>       {
> -      [self setVersion: 2];
> +      [self setVersion: 3];
>
>         [self exposeBinding: NSSelectedIndexBinding];
>         [self exposeBinding: NSFontBinding];
> @@ -550,7 +550,7 @@
>         [aCoder encodeValueOfObjCType: @encode(BOOL) at:&_draws_background];
>         [aCoder encodeValueOfObjCType: @encode(BOOL) at:&_truncated_label];
>         [aCoder encodeConditionalObject: _delegate];
> -      [aCoder encodeValueOfObjCType: "I" at:&_selected_item];
> +      [aCoder encodeValueOfObjCType: @encode(NSUInteger) at:&_selected_item];
>       }
>   }
>
> @@ -631,8 +631,17 @@
>         [aDecoder decodeValueOfObjCType: @encode(BOOL) at:&_draws_background];
>         [aDecoder decodeValueOfObjCType: @encode(BOOL) at:&_truncated_label];
>         _delegate = [aDecoder decodeObject];
> -      [aDecoder decodeValueOfObjCType: "I" at:&_selected_item];
> -      _selected = [_items objectAtIndex: _selected_item];
> +      if (version<  3)
> +       {
> +         int tmp;
> +          [aDecoder decodeValueOfObjCType: @encode(int) at:&tmp];
> +          _selected = [_items objectAtIndex: tmp];
> +       }
> +      else
> +       }
> +          [aDecoder decodeValueOfObjCType: @encode(NSUInteger) 
> at:&_selected_item];
> +          _selected = [_items objectAtIndex: _selected_item];
> +       }
>       }
>     return self;
>   }
>
>
>
> > David
> >
> > -- Sent from my Cray X1