GNU bug report logs - #22763
25.1.50; Feature Request -- A faster method to obtain line number at position.

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From: Lars Ingebrigtsen <larsi <at> gnus.org>
To: Stefan Monnier <monnier <at> iro.umontreal.ca>
Cc: 22763 <at> debbugs.gnu.org, Eli Zaretskii <eliz <at> gnu.org>, esq <at> lawlist.com
Subject: bug#22763: 25.1.50; Feature Request -- A faster method to obtain line number at position.
Date: Sun, 07 Feb 2021 21:42:30 +0100

Stefan Monnier <monnier <at> iro.umontreal.ca> writes:

>> So ... it's using the cache is only faster when we have monumentally
>> long lines, since memchr is so fast?  And in buffers with lines with
>> normal line lengths, it's 10x slower?  That sounds like a rather drastic
>> trade-off.
>
> Yes, the problem is when you have pathologically-long lines (typically,
> when the whole file has virtually no \n in it, so lines can reach
> multi-MB lengths).

Right, and in that case a cached version would definitely be faster on
repeated executions.  Why does display_count_lines (with no cache)
exist, then?  Historical reasons?

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

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