• Stewart Gordon (36/36) Jun 07 2004 Last night I was experimenting with sort. It didn't take me long to

Stewart Gordon <smjg_1998 yahoo.com> writes:

Last night I was experimenting with sort.  It didn't take me long to 
notice that it wasn't sorting properly.  It's a specific failure mode, 
whereby the array has effectively been cut in two and then pieced 
together the other way round.

Having looked at internal\qsort.d and finding that's not the problem, I 
then went into the TypeInfo stuff and found this:

     int compare(void *p1, void *p2)
     {
         return *cast(int *)p1 - *cast(int *)p2;
     }

No check for overflow.  So indeed, sort has no reason to break the 
circle at int.min rather than any other value.

The fix is straightforward: do it in the same way as for longs.

For int:

     int compare(void* p1, void* p2)
     {
         if (*cast(int*) p1 < *cast(int*) p2)
             return -1;
         else if (*cast(int*) p1 > *cast(int*) p2)
             return 1;
         return 0;
     }

For uint:

     int compare(void* p1, void* p2)
     {
         if (*cast(uint*) p1 < *cast(uint*) p2)
             return -1;
         else if (*cast(uint*) p1 > *cast(uint*) p2)
             return 1;
         return 0;
     }

Stewart.

-- 
My e-mail is valid but not my primary mailbox, aside from its being the 
unfortunate victim of intensive mail-bombing at the moment.  Please keep 
replies on the 'group where everyone may benefit.