From b25a5d9a5b9b786b118068cece225709a499597f Mon Sep 17 00:00:00 2001
From: Bastian Dehn <hhaalo@arcor.de>
Date: Fri, 27 Feb 2026 16:51:37 +0100
Subject: [PATCH] add wide char length detect

---
 src/rename.c         | 13 +++++++++++++
 src/rename.h         |  1 +
 tests/rename_tests.c | 40 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 54 insertions(+)

diff --git a/src/rename.c b/src/rename.c
index 60ccc46..e017bc7 100644
--- a/src/rename.c
+++ b/src/rename.c
@@ -3,6 +3,19 @@
 #include <string.h>
 #include "rename.h"
 
+unsigned int wide_char_length(const char character)
+{
+	unsigned int count = 0;
+	for (int i = 7; i > 0; i--) {
+		if (character >> i & 1)
+			count++;
+		else
+			break;
+	}
+
+	return count;
+}
+
 char* escape(const char* src)
 {
 	char* dest = malloc(sizeof(char) * STR_MAX_LENGTH);
diff --git a/src/rename.h b/src/rename.h
index 1378b53..86d9d43 100644
--- a/src/rename.h
+++ b/src/rename.h
@@ -32,6 +32,7 @@
 
 typedef char* (*rename_ptr)(const char* src);
 
+unsigned int wide_char_length(const char character);
 char* escape(const char* src);
 char* rename_point(const char* src);
 char* rename_lower(const char* src);
diff --git a/tests/rename_tests.c b/tests/rename_tests.c
index 1c7e340..94b7132 100644
--- a/tests/rename_tests.c
+++ b/tests/rename_tests.c
@@ -235,6 +235,42 @@ void rename_revert_ss()
 	output = NULL;
 }
 
+void no_wide_character()
+{
+	const char input = 0;
+
+	unsigned int length = wide_char_length(input);
+
+	assert_int_equal(length, 0);
+}
+
+void two_byte_wide_character()
+{
+	const char input = (char) 0x80;
+
+	unsigned int length = wide_char_length(input);
+
+	assert_int_equal(length, 1);
+}
+
+void three_byte_wide_character()
+{
+	const char input = (char) 0xc0;
+
+	unsigned int length = wide_char_length((char) 0xc0);
+
+	assert_int_equal(length, 2);
+}
+
+void four_byte_wide_character()
+{
+	const char input = 0xd0;
+
+	unsigned int length = wide_char_length((char) 0xe0);
+
+	assert_int_equal(length, 3);
+}
+
 int main()
 {
 	const struct CMUnitTest tests[] = {
@@ -257,6 +293,10 @@ int main()
 		cmocka_unit_test(rename_revert_ue),
 		cmocka_unit_test(rename_revert_Ue),
 		cmocka_unit_test(rename_revert_ss),
+		cmocka_unit_test(no_wide_character),
+		cmocka_unit_test(two_byte_wide_character),
+		cmocka_unit_test(three_byte_wide_character),
+		cmocka_unit_test(four_byte_wide_character),
 	};
 
 	return cmocka_run_group_tests(tests, NULL, NULL);
-- 
2.47.3