utils: utf8: change utf8_count_chars return to int

Change utf8_count_chars return type to int and drop thesys/types.h, this
way the function does not depend on posix types.

Signed-off-by: Fabio Baltieri <fabiobaltieri@google.com>

Author: fabiobaltieri

include/zephyr/sys/util_utf8.h

@@ -15,7 +15,6 @@
 #define ZEPHYR_INCLUDE_SYS_UTIL_UFT8_H_
 
 #include <stddef.h>
-#include <sys/types.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -81,7 +80,7 @@ char *utf8_lcpy(char *dst, const char *src, size_t n);
  * @return Number of UTF-8 characters in @p s on success or (negative) error code
  *  otherwise.
  */
-ssize_t utf8_count_chars(const char *s);
+int utf8_count_chars(const char *s);
 
 #ifdef __cplusplus
 }

lib/utils/utf8.c

@@ -84,7 +84,7 @@ char *utf8_lcpy(char *dst, const char *src, size_t n)
 	return dst;
 }
 
-ssize_t utf8_count_chars(const char *s)
+int utf8_count_chars(const char *s)
 {
 	ssize_t count = 0;
 	const char *p = s; /* getting a pointer to increment */

tests/unit/util/main.c

@@ -1008,24 +1008,24 @@ ZTEST(util, test_utf8_lcpy_null_termination)
 ZTEST(util, test_utf8_count_chars_ASCII)
 {
 	const char *test_str = "I have 15 char.";
-	ssize_t count = utf8_count_chars(test_str);
+	int count = utf8_count_chars(test_str);
 
 	zassert_equal(count, 15, "Failed to count ASCII");
 }
 
 ZTEST(util, test_utf8_count_chars_non_ASCII)
 {
 	const char *test_str = "Hello دنیا!🌍";
-	ssize_t count = utf8_count_chars(test_str);
+	int count = utf8_count_chars(test_str);
 
 	zassert_equal(count, 12, "Failed to count non-ASCII");
 }
 
 ZTEST(util, test_utf8_count_chars_invalid_utf)
 {
 	const char test_str[] = { (char)0x80, 0x00 };
-	ssize_t count = utf8_count_chars(test_str);
-	ssize_t expected_result = -EINVAL;
+	int count = utf8_count_chars(test_str);
+	int expected_result = -EINVAL;
 
 	zassert_equal(count, expected_result, "Failed to detect invalid UTF");
 }