lib: add glibc style strchrnul() variant

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>

1 files changed, 18 insertions, 0 deletions

diff --git a/lib/string.c b/lib/string.c
index af0295f79..317ae4fcc 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -302,6 +302,24 @@ char *strchr(const char *s, int c)
 EXPORT_SYMBOL(strchr);
 #endif
 
+#ifndef __HAVE_ARCH_STRCHRNUL
+/**
+ * strchrnul - Find and return a character in a string, or end of string
+ * @s: The string to be searched
+ * @c: The character to search for
+ *
+ * Returns pointer to first occurrence of 'c' in s. If c is not found, then
+ * return a pointer to the null byte at the end of s.
+ */
+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