Re: [PATCH 1/3] lib: add glibc style strchrnul() variant

From: Grant Likely
Date: Fri May 16 2014 - 11:01:11 EST


On Thu, 15 May 2014 15:19:00 -0700, Frank Rowand <frowand.list@xxxxxxxxx> wrote:
> On 5/13/2014 7:58 AM, Grant Likely wrote:
> > The strchrnul() variant helpfully returns a the end of the string
> > instead of a NULL if the requested character is not found. This can
> > simplify string parsing code since it doesn't need to expicitly check
> > for a NULL return. If a valid string pointer is passed in, then a valid
> > null terminated string will always come back out.
> >
> > Signed-off-by: Grant Likely <grant.likely@xxxxxxxxxx>
> > ---
> > include/linux/string.h | 3 +++
> > lib/string.c | 15 +++++++++++++++
> > 2 files changed, 18 insertions(+)
> >
> > diff --git a/include/linux/string.h b/include/linux/string.h
> > index ac889c5ea11b..d36977e029af 100644
> > --- a/include/linux/string.h
> > +++ b/include/linux/string.h
> > @@ -52,6 +52,9 @@ extern int strncasecmp(const char *s1, const char *s2, size_t n);
> > #ifndef __HAVE_ARCH_STRCHR
> > extern char * strchr(const char *,int);
> > #endif
> > +#ifndef __HAVE_ARCH_STRCHRNUL
> > +extern char * strchrnul(const char *,int);
> > +#endif
> > #ifndef __HAVE_ARCH_STRNCHR
> > extern char * strnchr(const char *, size_t, int);
> > #endif
> > diff --git a/lib/string.c b/lib/string.c
> > index 9b1f9062a202..059636f92c26 100644
> > --- a/lib/string.c
> > +++ b/lib/string.c
> > @@ -301,6 +301,21 @@ char *strchr(const char *s, int c)
> > EXPORT_SYMBOL(strchr);
> > #endif
> >
> > +#ifndef __HAVE_ARCH_STRCHRNUL
> > +/**
> > + * strchr - Find the first occurrence of a character in a string
>
> s/strchr/strchrnul/
>
> Add to the end of the description: if c is not found in s then return
> a pointer to the null byte at the end of s

Thanks, fixed.

>
> > + * @s: The string to be searched
> > + * @c: The character to search for
> > + */
> > +char *strchrnul(const char *s, int c)
> > +{
> > + while (*s && *s != (char)c)
> > + s++;
> > + return (char *)s;
> > +}
> > +EXPORT_SYMBOL(strchrnul);
> > +#endif
> > +
> > #ifndef __HAVE_ARCH_STRRCHR
> > /**
> > * strrchr - Find the last occurrence of a character in a string
> >
>

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