Re: [gobo-eiffel-develop] DS_LINKED_LIST_CURSOR.back

[Eric B. <er...@go...>]

Colin Paul Adams wrote:
>>>>>>"Eric" == Eric Bezault <er...@go...> writes:
>>>>>
> 
>     Eric> Hello Colin, I saw that in the following routines:
> 
>     Eric> 	XM_XSLT_CALL_TEMPLATE find_template XM_XSLT_FUNCTION
>     Eric> validate XM_XSLT_STYLESHEET build_indices
>     Eric> XM_XSLT_STYLE_ELEMENT stylesheet_function
> 
>     Eric> you call DS_LINKED_LIST_CURSOR.back. Performance-wise it is
>     Eric> not a good idea to traverse linked-list backwards,
>     Eric> especially if they have many items. You should rather use
>     Eric> DS_ARRAYED_LIST or DS_BILINKED_LIST instead.
> 
> OK.
> What happened is I used to use a DS_ARRAYED_LIST and changed it to a 
> DS_LINKED_LIST for some (good) reason. back wasn't being used in the
> routine that convinced me to change.
> So I'll change it to a DS_BILINKED_LIST.

Reasons to avoid DS_ARRAYED_LIST is when you have too many insertions
or deletions other than at the end of the list, or too many resizing.

Reasons to avoid DS_LINKED_LIST is when you have too many backward
traversals or calls to `index', or that it takes too much memory
space compared to arrayed lists.

Reasons to avoid DS_BILINKED_LIST is that it takes too much memory
space compared to linked lists.

Then, choosing one or the others kinds of lists is a trade-off
based on the usage we want to have with it.

-- 
Eric Bezault
mailto:er...@go...
http://www.gobosoft.com