From: Johannes Sixt <j6t@kdbg.org>
To: Jeff King <peff@peff.net>
Cc: Junio C Hamano <gitster@pobox.com>,
git@vger.kernel.org, Martin Koegler <martin.koegler@chello.at>
Subject: Re: [PATCH] zlib.c: use size_t for size
Date: Sat, 13 Oct 2018 10:43:24 +0200 [thread overview]
Message-ID: <2e7b2f4b-92c3-a583-5985-38090cc78c64@kdbg.org> (raw)
In-Reply-To: <20181013024624.GB15595@sigill.intra.peff.net>
Am 13.10.18 um 04:46 schrieb Jeff King:
> But no, right before that we have this line:
>
> offset -= win->offset;
>
> So offset is in fact no longer its original meaning of "offset into the
> packfile", but is now an offset of the specific request into the window
> we found.
>
> So I think it's correct, but it sure confused me. I wonder if another
> variable might help, like:
>
> size_t offset_in_window;
> ...
>
> /*
> * We know this difference will fit in a size_t, because our mmap
> * window by * definition can be no larger than a size_t.
> */
> offset_in_window = xsize_t(offset - win->offset);
> if (left)
> *left = win->len - offset_in_window;
> return win->base + offset_in_window;
>
> I dunno. Maybe it is overkill.
Thank you for your analysis. No, I don't think that such a new variable
would be overkill. It is important to make such knowledge of value
magnitudes explicit precisely because it reduces confusion and helps
reviewers of the code verify correctness.
-- Hannes
prev parent reply other threads:[~2018-10-13 8:43 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-12 7:07 [PATCH] zlib.c: use size_t for size Junio C Hamano
2018-10-12 9:54 ` Johannes Schindelin
2018-10-12 13:52 ` Junio C Hamano
2018-10-12 15:34 ` Johannes Schindelin
2018-10-12 23:23 ` Ramsay Jones
2018-10-12 20:42 ` [PATCH v2 1/1] " tboegi
2018-10-12 22:22 ` SZEDER Gábor
2018-10-13 5:00 ` Torsten Bögershausen
2018-10-14 2:16 ` Ramsay Jones
2018-10-14 2:31 ` Ramsay Jones
2018-10-14 2:52 ` Jeff King
2018-10-14 15:03 ` Ramsay Jones
2018-10-15 0:01 ` Jeff King
2018-10-15 0:41 ` Ramsay Jones
2018-10-15 4:22 ` Junio C Hamano
2018-10-15 5:54 ` Torsten Bögershausen
2018-10-13 2:38 ` [PATCH] " Jeff King
2018-10-13 2:46 ` Jeff King
2018-10-13 8:43 ` Johannes Sixt [this message]
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