LibC: Implement wcslcpy

Author: https://github.com/BertalanD
Commit: 13e6d9d71a
Pull-request: https://github.com/SerenityOS/serenity/pull/9378
Reviewed-by: https://github.com/ADKaster ✅
Reviewed-by: https://github.com/itamar8910
Reviewed-by: https://github.com/linusg ✅
Reviewed-by: https://github.com/nico
Reviewed-by: https://github.com/timschumi

Userland/Libraries/LibC/wchar.cpp

@@ -69,6 +69,18 @@ wchar_t* wcsncpy(wchar_t* dest, const wchar_t* src, size_t num)
     return original_dest;
 }
 
+size_t wcslcpy(wchar_t* dest, const wchar_t* src, size_t n)
+{
+    size_t i;
+    for (i = 0; i + 1 < n && src[i] != L'\0'; ++i)
+        dest[i] = src[i];
+    if (n)
+        dest[i] = L'\0';
+    for (; src[i] != L'\0'; ++i)
+        ; // Determine the length of src, don't copy.
+    return i;
+}
+
 int wcscmp(const wchar_t* s1, const wchar_t* s2)
 {
     while (*s1 == *s2++)