[PATCH] strstrip() API

Add a new strstrip() function to lib/string.c for removing leading and
trailing whitespace from a string.

Cc: Michael Holzheu <holzheu@de.ibm.com>
Acked-by: NIngo Oeser <ioe-lkml@rameria.de>
Acked-by: NJoern Engel <joern@wohnheim.fh-wedel.de>
Cc: Corey Minyard <minyard@acm.org>
Signed-off-by: NPekka Enberg <penberg@cs.helsinki.fi>
Acked-by: NMichael Holzheu <HOLZHEU@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

include/linux/string.h

@@ -56,6 +56,7 @@ extern char * strnchr(const char *, size_t, int);
 #ifndef __HAVE_ARCH_STRRCHR
 extern char * strrchr(const char *,int);
 #endif
+extern char * strstrip(char *);
 #ifndef __HAVE_ARCH_STRSTR
 extern char * strstr(const char *,const char *);
 #endif

lib/string.c

@@ -301,6 +301,36 @@ char *strnchr(const char *s, size_t count, int c)
 EXPORT_SYMBOL(strnchr);
 #endif
 
+/**
+ * strstrip - Removes leading and trailing whitespace from @s.
+ * @s: The string to be stripped.
+ *
+ * Note that the first trailing whitespace is replaced with a %NUL-terminator
+ * in the given string @s. Returns a pointer to the first non-whitespace
+ * character in @s.
+ */
+char *strstrip(char *s)
+{
+	size_t size;
+	char *end;
+
+	size = strlen(s);
+
+	if (!size)
+		return s;
+
+	end = s + size - 1;
+	while (end != s && isspace(*end))
+		end--;
+	*(end + 1) = '\0';
+
+	while (*s && isspace(*s))
+		s++;
+
+	return s;
+}
+EXPORT_SYMBOL(strstrip);
+
 #ifndef __HAVE_ARCH_STRLEN
 /**
  * strlen - Find the length of a string