Hi,
yep, you are right. But I think it's better to implement our own qsort
instead of moving list elements. List might be very large...
[EMAIL PROTECTED] wrote:
> Hello,
>
> Nobody uses gwlist_sort() but insect found. So I will describe it and
> propose fix for benefit of future generations.
>
> Forementioned function uses qsort(3) like this:
>
>> qsort(&GET(list, 0), list->len, sizeof(void*), cmp);
>
> And remember this code:
>
>> #define INDEX(list, i) (((list)->start + i) % (list)->tab_size)
>> #define GET(list, i) ((list)->tab[INDEX(list, i)])
>
> If tab array is wrapped this produces misbehavior. For example if we have
> tab_size = 7, len = 7, start = 1 qsort() will try to sort 7 elements
> starting from second, which mean it will try to pass into compare function
> bogus element past end of tab array, resulting crash or precious software.
>
> This probably should fix the problem:
>
> // if array is wrapped we need to merge parts into a single chunk
> if ((list->start + list->len) > list->tab_size) {
> if (list->len != list->tab_size)
> memmove(list->tab + INDEX(list, list->len),
> list->tab + list->start,
> (list->len - INDEX(list, list->len)) * sizeof(void
> *));
> list->start = 0;
> }
>
> qsort(&GET(list, 0), list->len, sizeof(void*), cmp);
>
>
> Best regards.
--
Thanks,
Alex
