From: Phillip Wood <phillip.wood123@gmail.com>
To: ZheNing Hu <adlternative@gmail.com>,
Felipe Contreras <felipe.contreras@gmail.com>
Cc: ZheNing Hu via GitGitGadget <gitgitgadget@gmail.com>,
Git List <git@vger.kernel.org>,
Junio C Hamano <gitster@pobox.com>,
Christian Couder <christian.couder@gmail.com>,
Hariom Verma <hariom18599@gmail.com>,
Karthik Nayak <karthik.188@gmail.com>,
Bagas Sanjaya <bagasdotme@gmail.com>, Jeff King <peff@peff.net>
Subject: Re: [PATCH 1/2] [GSOC] ref-filter: add %(raw) atom
Date: Sun, 30 May 2021 14:05:55 +0100 [thread overview]
Message-ID: <2c28515c-89b1-79dd-35a2-492eac6b7347@gmail.com> (raw)
In-Reply-To: <CAOLTT8TEkrxAgHvkCVXZDQpn0xSQAe_y7uMF89Q4QWwVd7MDcA@mail.gmail.com>
Hi ZheNing
On 30/05/2021 07:29, ZheNing Hu wrote:
> Felipe Contreras <felipe.contreras@gmail.com> 于2021年5月29日周六 下午11:24写道:
>>
>> Phillip Wood wrote:
>>> On 27/05/2021 17:36, Felipe Contreras wrote:
>>>> ZheNing Hu via GitGitGadget wrote:
>>>> [...]
>>>>> +static int memcasecmp(const void *vs1, const void *vs2, size_t n)
>>>>
>>>> Why void *? We can delcare as char *.
>>>
>>> If you look at how this function is used you'll see
>>> int (*cmp_fn)(const void *, const void *, size_t);
>>> cmp_fn = s->sort_flags & REF_SORTING_ICASE
>>> ? memcasecmp : memcmp;
>>
>> Yeah, but why?
>>
>> We know we are comparing two char *. Presumably the reason is that
>> memcmp and memcasecmp use void *, but that could be remedied with:
>>
>> cmp_fn = (int (*)(const char *, const char *, size_t))memcmp;
>>
>> That way the same cmp_fn could be used for the two cases.
>>
>> Either way I don't care particularly much. It also could be possible to
>> use void * and do the casting in tolower().
>>
>
> I agree with Phillip's point of view here:
> It would be better for memcasecmp and memcmp to be consistent.
>
>>>> (and I personally prefer lower to upper)
>>>
>>> We should be using tolower() as that is what POSIX specifies for
>>> strcasecmp() [1] which we are trying to emulate and there are cases[2] where
>>> (tolower(c1) == tolower(c2)) != (toupper(c1) == toupper(c2))
>>
>> That's true.
>>
>
> How about something like this:
>
> static int memcasecmp(const void *vs1, const void *vs2, size_t n)
> {
> - size_t i;
> - const char *s1 = (const char *)vs1;
> - const char *s2 = (const char *)vs2;
> -
> - for (i = 0; i < n; i++) {
> - unsigned char u1 = s1[i];
> - unsigned char u2 = s2[i];
> - int U1 = toupper (u1);
> - int U2 = toupper (u2);
> - int diff = (UCHAR_MAX <= INT_MAX ? U1 - U2
> - : U1 < U2 ? -1 : U2 < U1);
> + const char *s1 = (const void *)vs1;
> + const char *s2 = (const void *)vs2;
I think the new version looks fine apart from these casts. vs1 declared
as 'const void *' in the function signature so this cast does not do
anything. You could cast using (const char *) instead if you wanted but
that is not required as you can assign a 'const void *' to 'const
whatever *' without a cast.
Best Wishes
Phillip
> + const char *end = s1 + n;
> +
> + for (; s1 < end; s1++, s2++) {
> + int diff = tolower(*s1) - tolower(*s2);
> if (diff)
> return diff;
> }
> }
>
>> --
>> Felipe Contreras
>
> Thanks.
> --
> ZheNing Hu
>
next prev parent reply other threads:[~2021-05-30 13:06 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-27 14:43 [PATCH 0/2] [GSOC] ref-filter: add %(raw) atom ZheNing Hu via GitGitGadget
2021-05-27 14:43 ` [PATCH 1/2] " ZheNing Hu via GitGitGadget
2021-05-27 16:36 ` Felipe Contreras
2021-05-28 13:02 ` ZheNing Hu
2021-05-28 16:30 ` Felipe Contreras
2021-05-30 5:37 ` ZheNing Hu
2021-05-29 13:23 ` Phillip Wood
2021-05-29 15:24 ` Felipe Contreras
2021-05-29 17:23 ` Phillip Wood
2021-05-30 6:29 ` ZheNing Hu
2021-05-30 13:05 ` Phillip Wood [this message]
2021-05-31 14:15 ` ZheNing Hu
2021-05-31 15:35 ` Felipe Contreras
2021-05-30 6:26 ` ZheNing Hu
2021-05-30 13:02 ` Phillip Wood
2021-05-28 3:03 ` Junio C Hamano
2021-05-28 15:04 ` ZheNing Hu
2021-05-28 16:38 ` Felipe Contreras
2021-05-30 8:11 ` ZheNing Hu
2021-05-27 14:43 ` [PATCH 2/2] [GSOC] ref-filter: add %(header) atom ZheNing Hu via GitGitGadget
2021-05-27 16:37 ` Felipe Contreras
2021-05-28 3:06 ` Junio C Hamano
2021-05-28 4:36 ` Junio C Hamano
2021-05-28 15:19 ` ZheNing Hu
2021-05-27 15:39 ` [PATCH 0/2] [GSOC] ref-filter: add %(raw) atom Felipe Contreras
2021-05-30 13:01 ` [PATCH v2 " ZheNing Hu via GitGitGadget
2021-05-30 13:01 ` [PATCH v2 1/2] [GSOC] ref-filter: add obj-type check in grab contents ZheNing Hu via GitGitGadget
2021-05-31 5:34 ` Junio C Hamano
2021-05-30 13:01 ` [PATCH v2 2/2] [GSOC] ref-filter: add %(raw) atom ZheNing Hu via GitGitGadget
2021-05-31 0:44 ` Junio C Hamano
2021-05-31 14:35 ` ZheNing Hu
2021-06-01 9:54 ` Junio C Hamano
2021-06-01 11:05 ` ZheNing Hu
2021-05-31 4:04 ` Junio C Hamano
2021-05-31 14:40 ` ZheNing Hu
2021-06-01 8:54 ` Junio C Hamano
2021-06-01 11:00 ` ZheNing Hu
2021-06-01 13:48 ` Johannes Schindelin
2021-05-31 4:10 ` Junio C Hamano
2021-05-31 15:41 ` Felipe Contreras
2021-06-01 10:37 ` ZheNing Hu
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