From: Johannes Sixt <j6t@kdbg.org>
To: Johannes Schindelin <Johannes.Schindelin@gmx.de>,
Junio C Hamano <gitster@pobox.com>
Cc: Johannes Schindelin via GitGitGadget <gitgitgadget@gmail.com>,
git@vger.kernel.org, Denton Liu <liu.denton@gmail.com>
Subject: Re: [PATCH v2 02/13] msvc: avoid using minus operator on unsigned types
Date: Fri, 4 Oct 2019 19:09:43 +0200 [thread overview]
Message-ID: <ae6a64f4-8f46-cbaf-5004-defc316c5157@kdbg.org> (raw)
In-Reply-To: <nycvar.QRO.7.76.6.1910041154120.46@tvgsbejvaqbjf.bet>
Am 04.10.19 um 11:55 schrieb Johannes Schindelin:
> On Fri, 4 Oct 2019, Junio C Hamano wrote:
>> These three look good and too similar to each other, which makes me
>> wonder if we want to allow them simply write
>>
>> return insert_pos_as_negative_offset(nr);
>>
>> with something like
>>
>> static int insert_pos_as_negative_offset(uintmax_t nr)
>> {
>> if (INT_MAX < nr)
>> die("overflow: -1 - %"PRIuMAX, nr);
>> return -1 - (int)nr;
>> }
>>
>> to avoid repetition.
>
> I tried not to do that because there are two different data types in
> play: `unsigned int` and `size_t`. But I guess by making this an
> `inline` function, compilers can optimize for the common case and avoid
> casting _twice_.
>
> Will be fixed in v2,
IMHO, if you don't accompany insert_pos_as_negative_offset() with a
corresponding extract_pos_and_found_condition() and use it everywhere,
it is more obfuscating than necessary.
The *real* problem to solve is to ensure that the index/cache does not
grow so large that 32-bit indexes would be needed. Then the calculation
that you want to hide here cannot overflow.
-- Hannes
next prev parent reply other threads:[~2019-10-04 17:09 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-26 8:30 [PATCH 00/13] ci: include a Visual Studio build & test in our Azure Pipeline Johannes Schindelin via GitGitGadget
2019-09-26 8:30 ` [PATCH 01/13] push: do not pretend to return `int` from `die_push_simple()` Johannes Schindelin via GitGitGadget
2019-09-26 8:30 ` [PATCH 02/13] msvc: avoid using minus operator on unsigned types Johannes Schindelin via GitGitGadget
2019-09-26 17:20 ` Denton Liu
2019-09-26 21:01 ` Johannes Schindelin
2019-09-26 23:57 ` Denton Liu
2019-09-30 9:50 ` Johannes Schindelin
2019-09-26 8:30 ` [PATCH 03/13] winansi: use FLEX_ARRAY to avoid compiler warning Johannes Schindelin via GitGitGadget
2019-09-26 8:30 ` [PATCH 04/13] compat/win32/path-utils.h: add #include guards Johannes Schindelin via GitGitGadget
2019-09-26 8:30 ` [PATCH 05/13] msvc: ignore some libraries when linking Johannes Schindelin via GitGitGadget
2019-09-26 8:30 ` [PATCH 06/13] msvc: handle DEVELOPER=1 Johannes Schindelin via GitGitGadget
2019-09-26 8:30 ` [PATCH 07/13] msvc: work around a bug in GetEnvironmentVariable() Johannes Schindelin via GitGitGadget
2019-09-26 8:30 ` [PATCH 08/13] vcxproj: only copy `git-remote-http.exe` once it was built Johannes Schindelin via GitGitGadget
2019-09-26 8:30 ` [PATCH 09/13] vcxproj: include more generated files Johannes Schindelin via GitGitGadget
2019-09-26 8:30 ` [PATCH 10/13] test-tool run-command: learn to run (parts of) the testsuite Johannes Schindelin via GitGitGadget
2019-09-26 8:30 ` [PATCH 11/13] tests: let --immediate and --write-junit-xml play well together Johannes Schindelin via GitGitGadget
2019-09-28 22:22 ` Junio C Hamano
2019-09-30 9:52 ` Johannes Schindelin
2019-09-26 8:30 ` [PATCH 12/13] ci: really use shallow clones on Azure Pipelines Johannes Schindelin via GitGitGadget
2019-09-26 8:30 ` [PATCH 13/13] ci: also build and test with MS Visual Studio " Johannes Schindelin via GitGitGadget
2019-09-30 9:55 ` [PATCH v2 00/13] ci: include a Visual Studio build & test in our Azure Pipeline Johannes Schindelin via GitGitGadget
2019-09-30 9:55 ` [PATCH v2 02/13] msvc: avoid using minus operator on unsigned types Johannes Schindelin via GitGitGadget
2019-10-03 22:44 ` Junio C Hamano
2019-10-04 9:55 ` Johannes Schindelin
2019-10-04 17:09 ` Johannes Sixt [this message]
2019-10-04 21:24 ` Johannes Schindelin
2019-10-06 0:02 ` Junio C Hamano
2019-10-06 10:53 ` Johannes Sixt
2019-10-08 12:04 ` Johannes Schindelin
2019-10-08 21:13 ` Johannes Sixt
2019-09-30 9:55 ` [PATCH v2 01/13] push: do not pretend to return `int` from `die_push_simple()` Johannes Schindelin via GitGitGadget
2019-10-03 22:37 ` Junio C Hamano
2019-10-04 9:36 ` Johannes Schindelin
2019-09-30 9:55 ` [PATCH v2 03/13] winansi: use FLEX_ARRAY to avoid compiler warning Johannes Schindelin via GitGitGadget
2019-09-30 9:55 ` [PATCH v2 04/13] compat/win32/path-utils.h: add #include guards Johannes Schindelin via GitGitGadget
2019-09-30 9:55 ` [PATCH v2 05/13] msvc: ignore some libraries when linking Johannes Schindelin via GitGitGadget
2019-09-30 9:55 ` [PATCH v2 06/13] msvc: handle DEVELOPER=1 Johannes Schindelin via GitGitGadget
2019-09-30 9:55 ` [PATCH v2 07/13] msvc: work around a bug in GetEnvironmentVariable() Johannes Schindelin via GitGitGadget
2019-09-30 9:55 ` [PATCH v2 08/13] vcxproj: only copy `git-remote-http.exe` once it was built Johannes Schindelin via GitGitGadget
2019-09-30 9:55 ` [PATCH v2 09/13] vcxproj: include more generated files Johannes Schindelin via GitGitGadget
2019-09-30 9:55 ` [PATCH v2 10/13] test-tool run-command: learn to run (parts of) the testsuite Johannes Schindelin via GitGitGadget
2019-09-30 9:55 ` [PATCH v2 11/13] tests: let --immediate and --write-junit-xml play well together Johannes Schindelin via GitGitGadget
2019-09-30 9:55 ` [PATCH v2 13/13] ci: also build and test with MS Visual Studio on Azure Pipelines Johannes Schindelin via GitGitGadget
2019-09-30 9:55 ` [PATCH v2 12/13] ci: really use shallow clones " Johannes Schindelin via GitGitGadget
2019-10-04 15:09 ` [PATCH v3 00/13] ci: include a Visual Studio build & test in our Azure Pipeline Johannes Schindelin via GitGitGadget
2019-10-04 15:09 ` [PATCH v3 01/13] push: do not pretend to return `int` from `die_push_simple()` Johannes Schindelin via GitGitGadget
2019-10-04 15:09 ` [PATCH v3 02/13] msvc: avoid using minus operator on unsigned types Johannes Schindelin via GitGitGadget
2019-10-04 15:09 ` [PATCH v3 03/13] winansi: use FLEX_ARRAY to avoid compiler warning Johannes Schindelin via GitGitGadget
2019-10-07 19:16 ` Alban Gruin
2019-10-04 15:09 ` [PATCH v3 04/13] compat/win32/path-utils.h: add #include guards Johannes Schindelin via GitGitGadget
2019-10-04 15:09 ` [PATCH v3 05/13] msvc: ignore some libraries when linking Johannes Schindelin via GitGitGadget
2019-10-04 15:09 ` [PATCH v3 07/13] msvc: work around a bug in GetEnvironmentVariable() Johannes Schindelin via GitGitGadget
2019-10-04 15:09 ` [PATCH v3 06/13] msvc: handle DEVELOPER=1 Johannes Schindelin via GitGitGadget
2019-10-04 15:09 ` [PATCH v3 08/13] vcxproj: only copy `git-remote-http.exe` once it was built Johannes Schindelin via GitGitGadget
2019-10-04 15:09 ` [PATCH v3 09/13] vcxproj: include more generated files Johannes Schindelin via GitGitGadget
2019-10-04 15:09 ` [PATCH v3 10/13] test-tool run-command: learn to run (parts of) the testsuite Johannes Schindelin via GitGitGadget
2019-10-04 15:09 ` [PATCH v3 11/13] tests: let --immediate and --write-junit-xml play well together Johannes Schindelin via GitGitGadget
2019-10-04 15:09 ` [PATCH v3 12/13] ci: really use shallow clones on Azure Pipelines Johannes Schindelin via GitGitGadget
2019-10-04 15:09 ` [PATCH v3 13/13] ci: also build and test with MS Visual Studio " Johannes Schindelin via GitGitGadget
2019-10-06 0:19 ` [PATCH v3 00/13] ci: include a Visual Studio build & test in our Azure Pipeline Junio C Hamano
2019-10-06 10:45 ` Johannes Schindelin
2019-10-06 20:38 ` Johannes Schindelin
2019-10-07 1:14 ` Junio C Hamano
2019-10-07 21:51 ` Johannes Schindelin
2019-10-08 2:19 ` Junio C Hamano
2019-10-08 12:46 ` Johannes Schindelin
2019-10-09 13:57 ` Philip Oakley
2019-10-10 9:03 ` Johannes Schindelin
2019-10-10 10:12 ` Philip Oakley
2019-10-07 0:59 ` Junio C Hamano
2019-10-07 16:08 ` Thomas Gummerer
2019-10-11 22:06 ` Johannes Schindelin
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