string: provide strends()

Implement a function for checking if a string ends with a different
string and add its kunit test cases.

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20251112-gpio-shared-v4-1-b51f97b1abd8@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

diff --git a/include/linux/string.h b/include/linux/string.h
index fdd3442c6bcbd786e177b6e87358e1065a0ffafc..929d05d1247c76eb9011fe34250b487834b2d3c9 100644 (file)
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -562,4 +562,22 @@ static inline bool strstarts(const char *str, const char *prefix)
        return strncmp(str, prefix, strlen(prefix)) == 0;
 }
 
+/**
+ * strends - Check if a string ends with another string.
+ * @str - NULL-terminated string to check against @suffix
+ * @suffix - NULL-terminated string defining the suffix to look for in @str
+ *
+ * Returns:
+ * True if @str ends with @suffix. False in all other cases.
+ */
+static inline bool strends(const char *str, const char *suffix)
+{
+       unsigned int str_len = strlen(str), suffix_len = strlen(suffix);
+
+       if (str_len < suffix_len)
+               return false;
+
+       return !(strcmp(str + str_len - suffix_len, suffix));
+}
+
 #endif /* _LINUX_STRING_H_ */

diff --git a/lib/tests/string_kunit.c b/lib/tests/string_kunit.c
index 0ed7448a26d3aa0fe9e2a6a894d4c49c2c0b86e0..f9a8e557ba7734c9848d58ff986407d8000f52ee 100644 (file)
--- a/lib/tests/string_kunit.c
+++ b/lib/tests/string_kunit.c
@@ -602,6 +602,18 @@ static void string_test_memtostr(struct kunit *test)
        KUNIT_EXPECT_EQ(test, dest[7], '\0');
 }
 
+static void string_test_strends(struct kunit *test)
+{
+       KUNIT_EXPECT_TRUE(test, strends("foo-bar", "bar"));
+       KUNIT_EXPECT_TRUE(test, strends("foo-bar", "-bar"));
+       KUNIT_EXPECT_TRUE(test, strends("foobar", "foobar"));
+       KUNIT_EXPECT_TRUE(test, strends("foobar", ""));
+       KUNIT_EXPECT_FALSE(test, strends("bar", "foobar"));
+       KUNIT_EXPECT_FALSE(test, strends("", "foo"));
+       KUNIT_EXPECT_FALSE(test, strends("foobar", "ba"));
+       KUNIT_EXPECT_TRUE(test, strends("", ""));
+}
+
 static struct kunit_case string_test_cases[] = {
        KUNIT_CASE(string_test_memset16),
        KUNIT_CASE(string_test_memset32),
@@ -623,6 +635,7 @@ static struct kunit_case string_test_cases[] = {
        KUNIT_CASE(string_test_strlcat),
        KUNIT_CASE(string_test_strtomem),
        KUNIT_CASE(string_test_memtostr),
+       KUNIT_CASE(string_test_strends),
        {}
 };