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[146.198.22.11]) by smtp.googlemail.com with ESMTPSA id u17sm13662313wrt.61.2021.05.30.06.02.18 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 30 May 2021 06:02:18 -0700 (PDT) Subject: Re: [PATCH 1/2] [GSOC] ref-filter: add %(raw) atom To: ZheNing Hu Cc: Felipe Contreras , ZheNing Hu via GitGitGadget , Git List , Junio C Hamano , Christian Couder , Hariom Verma , Karthik Nayak , Bagas Sanjaya , Jeff King References: <60afca827a28f_265302085b@natae.notmuch> <13c63e79-27fd-58d5-9a4c-6b58c40ef4b8@gmail.com> From: Phillip Wood Message-ID: Date: Sun, 30 May 2021 14:02:17 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.2 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Hi ZheNing On 30/05/2021 07:26, ZheNing Hu wrote: > Phillip Wood 于2021年5月29日周六 下午9:23写道： >> >> On 27/05/2021 17:36, Felipe Contreras wrote: >>> ZheNing Hu via GitGitGadget wrote: >>> [...] >>> All we have to do is define the end point, and then we don't need i: >>> >>> static int memcasecmp(const char *s1, const char *s2, size_t n) >>> { >>> const char *end = s1 + n; >>> for (; s1 < end; s1++, s2++) { >>> int diff = tolower(*s1) - tolower(*s2); >>> if (diff) >>> return diff; >>> } >>> return 0; >>> } >>> >>> (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)) >> > > I don’t know if we overlooked a fact: This static `memcasecmp()` > is not a POSIX version. `tolower()` or `toupper()` are in git-compat-util.h, > sane_istest('\0', GIT_ALPHA) == false . So in `sane_case()`, whatever > `tolower()`, `toupper()`, they just return '\0' itself. Well spotted, thanks for pointing that out. So memcasecmp() and strcasecmp() may give different results. I'm not sure if that matters - as I understand it the main use for the 'raw' atom is with `git cat-file --batch` which does not support sorting. Also although strcasecmp() uses the current locale it does a byte-by-byte comparison so it is effectively ASCII only for UTF-8 anyway. Best Wishes Phillip >> Best Wishes >> >> Phillip >> >> [1] https://pubs.opengroup.org/onlinepubs/9699919799/ >> [2] https://en.wikipedia.org/wiki/Dotted_and_dotless_I#In_computing >> > > Thanks. > -- > ZhenNing Hu >