| Message ID | 1399993115-21552-2-git-send-email-grant.likely@linaro.org |
|---|---|
| State | New |
| Headers | show |
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@linaro.org> > --- > 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 > + * @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 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
On Thu, 15 May 2014 15:19:00 -0700, Frank Rowand <frowand.list@gmail.com> 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@linaro.org> > > --- > > 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 > > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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: 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
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@linaro.org> --- include/linux/string.h | 3 +++ lib/string.c | 15 +++++++++++++++ 2 files changed, 18 insertions(+)