On the following sentence: while (*s && isspace(*s)) s++;
If *s == 0, isspace() evaluates to ((_ctype[*s] & 0x20) != 0), which evaluates to ((0x08 & 0x20) != 0) which equals to 0 as well. If *s == 1, we depend on isspace() result anyway.
In other words, "a char equals zero is never a space". So remove this check. Also, *s != 0 is by far the most common case (non-empty string).
Signed-off-by: André Goddard Rosa andre.goddard@gmail.com --- include/linux/string.h | 1 + lib/string.c | 19 +++++++++++++++---- 2 files changed, 16 insertions(+), 4 deletions(-)
diff --git a/include/linux/string.h b/include/linux/string.h index b850886..3bba9ee 100644 --- a/include/linux/string.h +++ b/include/linux/string.h @@ -62,6 +62,7 @@ extern char * strnchr(const char *, size_t, int); #ifndef __HAVE_ARCH_STRRCHR extern char * strrchr(const char *,int); #endif +extern const char * __must_check skip_spaces(const char *); extern char * __must_check strstrip(char *); #ifndef __HAVE_ARCH_STRSTR extern char * strstr(const char *,const char *); diff --git a/lib/string.c b/lib/string.c index b19b87a..d9a51d5 100644 --- a/lib/string.c +++ b/lib/string.c @@ -330,6 +330,20 @@ EXPORT_SYMBOL(strnchr); #endif
/** + * skip_spaces - Removes leading whitespace from @s. + * @s: The string to be stripped. + * + * Returns a pointer to the first non-whitespace character in @s. + */ +const char *skip_spaces(const char *str) +{ + while (isspace(*str)) + ++str; + return str; +} +EXPORT_SYMBOL(skip_spaces); + +/** * strstrip - Removes leading and trailing whitespace from @s. * @s: The string to be stripped. * @@ -352,10 +366,7 @@ char *strstrip(char *s) end--; *(end + 1) = '\0';
- while (*s && isspace(*s)) - s++; - - return s; + return (char *)skip_spaces(s); } EXPORT_SYMBOL(strstrip);