refactor: refactor old IOHelper.

- move pointer left padding macro into single header file.
- move utf8 fopen into single header but not finished.
- add testbench for pointer left padding macro.
- add system pointer size detector according to new migrated features requested.

src/yycc/patch/fopen.cpp

@@ -0,0 +1,35 @@
+#include "fopen.hpp"
+#include "../macro/os_detector.hpp"
+#include "../string/reinterpret.hpp"
+
+#if defined(YYCC_OS_WINDOWS)
+#include "../windows/import_guard_head.hpp"
+#include <Windows.h>
+#include "../windows/import_guard_tail.hpp"
+#endif
+
+#define REINTERPRET ::yycc::string::reinterpret
+
+namespace yycc::patch::fopen {
+
+    std::FILE* fopen(const char8_t* u8_filepath, const char8_t* u8_mode) {
+        // TODO: Fix this after finish Windows encoding
+// #if defined(YYCC_OS_WINDOWS)
+
+//         // convert mode and file path to wchar
+//         std::wstring wmode, wpath;
+//         if (!YYCC::EncodingHelper::UTF8ToWchar(u8_mode, wmode))
+//             return nullptr;
+//         if (!YYCC::EncodingHelper::UTF8ToWchar(u8_filepath, wpath))
+//             return nullptr;
+
+//         // call microsoft specified fopen which support wchar as argument.
+//         return _wfopen(wpath.c_str(), wmode.c_str());
+
+// #else
+//         return std::fopen(REINTERPRET::as_ordinary(u8_filepath), REINTERPRET::as_ordinary(u8_mode));
+// #endif
+        return std::fopen(REINTERPRET::as_ordinary(u8_filepath), REINTERPRET::as_ordinary(u8_mode));
+    }
+
+}