Re: Implementing NSFastEnumeration

Hi Christiaan,

On Thu, 1 Oct 2009 18:30:15 +0200, Christiaan Hofman wrote:
>
> [...] The
> other thing is that I want to enumerate the underlying array of keys
> first. I tried something along these lines:

How about _replacing_ the key in itemsPtr[i] with the value as you go  
along?  Something like this: (Achtung, Mailware!)

- (NSUInteger)countByEnumeratingWithState:(NSFastEnumerationState *)state
{
	NSUInteger i, count = [keys countByEnumeratingWithState:state
objects:stackbuf count:len];
	for (i = 0; i < count; i++)
	{
		id key = state->itemsPtr[i];
		id value = [values objectForKey:key];
		state->itemsPtr[i] = value;
		//stackbuf[i] = value;
	}
	//state->itemsPtr = stackbuf;
	return count;
}

> While this works for small arrays, for larger arrays this gives a
> memory access crasher. The reason seems to be that NSArray can return
> more items than len (the size of stackbuf) in a single call.
>
> Would there be a way to modify this implementation to work? Or am I
> forced to get the objects from keys without using fast enumeration (in  
> which case fast enumeration becomes hardly fast)?

HTH,
Regards,

--Tom.