linux-kernel - Re: [PATCH v2 0/7] lib: string: add functions to case-convert strings

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Date:	Tue, 05 Jul 2016 15:14:34 -0700
From:	Joe Perches <joe@...ches.com>
To:	Markus Mayer <mmayer@...adcom.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Al Viro <viro@...iv.linux.org.uk>,
	Rasmus Villemoes <linux@...musvillemoes.dk>,
	Chris Metcalf <cmetcalf@...hip.com>,
	Kees Cook <keescook@...omium.org>
Cc:	dri-devel@...ts.freedesktop.org, nouveau@...ts.freedesktop.org,
	linux-acpi@...r.kernel.org, speakup@...ux-speakup.org,
	devel@...verdev.osuosl.org, linux-scsi@...r.kernel.org,
	target-devel@...r.kernel.org, linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 0/7] lib: string: add functions to case-convert
 strings

On Tue, 2016-07-05 at 13:47 -0700, Markus Mayer wrote:
> This series introduces a family of generic string case conversion
> functions. This kind of functionality is needed in several places in
> the kernel. Right now, everybody seems to be implementing their own
> copy of this functionality.
> 
> Based on the discussion of the previous version of this series[1] and
> the use cases found in the kernel, it does look like having several
> flavours of case conversion functions is beneficial. The use cases fall
> into three categories:
>     - copying a string and converting the case while specifying a
>       maximum length to mimic strncpy()
>     - copying a string and converting the case without specifying a
>       length to mimic strcpy()
>     - converting the case of a string in-place (i.e. modifying the
>       string that was passed in)
> 
> Consequently, I am proposing these new functions:
>     char *strncpytoupper(char *dst, const char *src, size_t len);
>     char *strncpytolower(char *dst, const char *src, size_t len);
>     char *strcpytoupper(char *dst, const char *src);
>     char *strcpytolower(char *dst, const char *src);
>     char *strtoupper(char *s);
>     char *strtolower(char *s);

I think there isn't much value in anything other
than strto<upper|lower>.

Using str[n]cpy followed by strto<upper|lower> is
pretty obvious and rarely used anyway.