[tip:perf/core] tools lib: Adopt skip_spaces() from the kernel sources

[tip-bot for Arnaldo Carvalho de Melo]

Commit-ID:  7bd330de43fd5693e90be13dac7fbd9af3b6335d
Gitweb:     https://git.kernel.org/tip/7bd330de43fd5693e90be13dac7fbd9af3b6335d
Author:     Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
AuthorDate: Tue, 25 Jun 2019 21:23:18 -0300
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Tue, 25 Jun 2019 21:23:18 -0300

tools lib: Adopt skip_spaces() from the kernel sources

Same implementation, will be used to replace ad-hoc equivalent code in
tools/.

Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Andrà Goddard Rosa <andre.goddard@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Link: https://lkml.kernel.org/n/tip-dig691cg9ripvoiprpidthw7@xxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/include/linux/string.h |  4 +++-
 tools/lib/string.c           | 14 ++++++++++++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/tools/include/linux/string.h b/tools/include/linux/string.h
index 6c3e2cc274c5..cee239350a6b 100644
--- a/tools/include/linux/string.h
+++ b/tools/include/linux/string.h
@@ -29,4 +29,6 @@ static inline bool strstarts(const char *str, const char *prefix)
 	return strncmp(str, prefix, strlen(prefix)) == 0;
 }
 
-#endif /* _LINUX_STRING_H_ */
+extern char * __must_check skip_spaces(const char *);
+
+#endif /* _TOOLS_LINUX_STRING_H_ */
diff --git a/tools/lib/string.c b/tools/lib/string.c
index 93b3d4b6feac..50d400822bb3 100644
--- a/tools/lib/string.c
+++ b/tools/lib/string.c
@@ -17,6 +17,7 @@
 #include <string.h>
 #include <errno.h>
 #include <linux/string.h>
+#include <linux/ctype.h>
 #include <linux/compiler.h>
 
 /**
@@ -106,3 +107,16 @@ size_t __weak strlcpy(char *dest, const char *src, size_t size)
 	}
 	return ret;
 }
+
+/**
+ * skip_spaces - Removes leading whitespace from @str.
+ * @str: The string to be stripped.
+ *
+ * Returns a pointer to the first non-whitespace character in @str.
+ */
+char *skip_spaces(const char *str)
+{
+	while (isspace(*str))
+		++str;
+	return (char *)str;
+}