From: "Gerd Möllmann" <gerd.moellmann@gmail.com>
To: Eli Zaretskii <eliz@gnu.org>
Cc: andreyorst@gmail.com, 56683@debbugs.gnu.org, gregory@heytings.org
Subject: bug#56683: 29.0.50; long lines fix doesn't work correctly when lines are truncated
Date: Fri, 22 Jul 2022 14:56:22 +0200 [thread overview]
Message-ID: <m2mtd1tifd.fsf@Mini.fritz.box> (raw)
In-Reply-To: <835yjpl5vm.fsf@gnu.org> (Eli Zaretskii's message of "Fri, 22 Jul 2022 14:54:37 +0300")
Eli Zaretskii <eliz@gnu.org> writes:
>> From: Gerd Möllmann <gerd.moellmann@gmail.com>
>
> Yes, integer overflow. This code:
>
> init_to_row_start (&it, w, cursor_row);
> if (hscl)
> it.first_visible_x = window_hscroll_limited (w, it.f)
> * FRAME_COLUMN_WIDTH (it.f);
> it.last_visible_x = DISP_INFINITY;
> move_it_in_display_line_to (&it, pt, -1, MOVE_TO_POS);
>
> will keep producing glyphs inside move_it_in_display_line_to until
> it gets to the position of point. While producing glyphs,
> it.current_x is incremented by the pixel-width of each produced
> glyph. After a large enough number of produced glyphs, it.current_x
> will overflow INT_MAX.
Right. I am not worried about that:
It takes a lot of iterations until the ints overflow. The largest
positive 32-bit integer is very roughly 2 * 10^9. With a font width of
of 10 pixels, that would mean 2 * 10^8 characters (200 Mb), and so on
with wider fonts.
Se that being said, what I orignally wanted to ask, was:
>> The thing you implemented in set_iterator_to_next we talked about.
>>
>> if (max_redisplay_ticks > 0)
>> update_redisplay_ticks (1, it->w);
>
> I understood that part, but not the "should be burn to much time
> because of the infinite last x" part, even if I replace "to" with
> "too".
Sorry for the typo: s/be/we, i.e. "if we burn...". What I meant to ask
is if the check above doesn't lead to a signal anyway long before we
reach the overflow.
next prev parent reply other threads:[~2022-07-22 12:56 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-21 18:49 bug#56683: 29.0.50; long lines fix doesn't work correctly when lines are truncated Andrey Listopadov
2022-07-21 19:45 ` Gregory Heytings
2022-07-21 19:57 ` Eli Zaretskii
2022-07-21 20:15 ` Gregory Heytings
2022-07-22 6:13 ` Eli Zaretskii
2022-07-22 6:51 ` Gerd Möllmann
2022-07-22 7:28 ` Eli Zaretskii
2022-07-22 7:52 ` Gerd Möllmann
2022-07-22 11:54 ` Eli Zaretskii
2022-07-22 12:56 ` Gerd Möllmann [this message]
2022-07-22 13:36 ` Eli Zaretskii
2022-07-22 13:54 ` Gerd Möllmann
2022-07-22 14:35 ` Eli Zaretskii
2022-07-25 22:22 ` Gregory Heytings
2022-07-26 7:12 ` Andrey Listopadov
2022-07-26 7:32 ` Gregory Heytings
2022-07-26 12:15 ` Eli Zaretskii
2022-07-26 11:42 ` Eli Zaretskii
2022-07-26 12:17 ` Gregory Heytings
2022-07-26 12:37 ` Eli Zaretskii
2022-07-26 12:50 ` Gregory Heytings
2022-07-26 13:15 ` Eli Zaretskii
2022-07-26 13:25 ` Gregory Heytings
2022-07-26 17:26 ` Eli Zaretskii
2022-07-26 20:14 ` Gregory Heytings
2022-07-22 6:53 ` Gerd Möllmann
2022-07-22 7:31 ` Eli Zaretskii
2022-07-22 7:53 ` Gerd Möllmann
2022-07-22 11:01 ` Eli Zaretskii
2022-07-21 20:31 ` Andrey Listopadov
2022-07-21 20:52 ` Gregory Heytings
2022-07-22 5:03 ` Andrey Listopadov
2022-07-22 6:34 ` Gregory Heytings
2022-07-22 6:30 ` Eli Zaretskii
2022-07-22 7:28 ` Gerd Möllmann
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