Re: bug in GNU Classpath LinkedList implementation

[Stuart Ballard]

Adam Welc wrote:
> 
> Hi,
> I am currently working on the implementation of the open source Java
> Virtual Machine and we are using GNU Classpath libraries. I am using
> LinkedList.class as a queue and I found a bug in the implementation of
> methods providing this functionality - removeLast() and removeFirst().
> The problem is that the values of "last" and "first" variables
> (respectively) are not updated. Corrrected code is given below (added
> lines are ended with // ADDED):

I am forwarding this message to the Classpath list (address@hidden).
Since I last touched the code, LinkedList has been completely rewritten;
I don't know the new code at all. Could whoever it was that did this
rewrite (Tom?) take a look at these changes and reply to Adam?

Thanks,
Stuart.

> 
>   public Object removeFirst()
>   {
>     if (size == 0)
>       throw new NoSuchElementException();
>     size--;
>     modCount++;
>     Object r = first.data;
> 
>     if (first.next != null)
>       first.next.previous = null;
> 
>     first = first.next;  // ADDED
> 
>     return r;
>   }
> 
>   public Object removeLast()
>   {
>     if (size == 0)
>       throw new NoSuchElementException();
>     size--;
>     modCount++;
>     Object r = last.data;
> 
>     if (last.previous != null)
>       last.previous.next = null;
>     
>     last = last.previous;  // ADDED
> 
>     return r;
>   }
> 
>                         Sincerely
> 
>                                 Adam Welc
> 
> --
> Adam Welc
> Computer Science Building, room 274
> West Lafayette, IN 47906
> Telephone number (work): (765) 4947836
> 
> http:// www.cs.purdue.edu/homes/welc