On Thu, Aug 20, 2009 at 2:14 PM, Kyle Sluder<[email protected]> wrote:
> On Thu, Aug 20, 2009 at 2:01 PM, Clark Cox<[email protected]> wrote:
>> Yes, and two different objects will have different pointer values. If
>> the hash is based on the pointer values, then two different objects
>> cannot have the same hash, regardless of whether or not they are
>> equal. Hence, that implementation of hash is broken for any object
>> that does anything other than a pointer comparison in -isEqual:.
>
> I thought we were talking about -hash just returning zero?
>
> --Kyle Sluder
>
No, we were talking about:
> It is, but you can generally do better than just returning 0, usually by just
> extracting some bits from 'self', ala
>
> -(NSUInteger)hash
> {
> uintptr_t hash = (uintptr_t)self;
> return (hash >> 4);
> }
--
Clark S. Cox III
[email protected]
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