feat: basically finish parser helper.

- basically finish parser helper, including TryParse, Parse and ToString.
- only Parse has been tested. other test should be filled in future.

src/IOHelper.cpp

@@ -6,19 +6,29 @@
 #include <iostream>
 #include <string>
 
+#include "WinImportPrefix.hpp"
+#include <Windows.h>
+#include <io.h>
+#include <fcntl.h>
+#include "WinImportSuffix.hpp"
+
 namespace YYCC::IOHelper {
 
-	FILE* FOpen(const char* u8_filepath, const char* u8_mode) {
-		std::wstring wmode, wpath;
-		bool suc = YYCC::EncodingHelper::CharToWchar(u8_mode, wmode, CP_UTF8);
-		suc = suc && YYCC::EncodingHelper::CharToWchar(u8_filepath, wpath, CP_UTF8);
+	bool futf8(FILE* fs) {
+		// https://learn.microsoft.com/en-us/cpp/c-runtime-library/reference/setmode?view=msvc-170
+		return _setmode(_fileno(fs), _O_U8TEXT) != -1;
+	}
 
-		if (suc) {
-			return _wfopen(wpath.c_str(), wmode.c_str());
-		} else {
-			// fallback
-			return std::fopen(u8_filepath, u8_mode);
-		}
+	FILE* fopen(const char* u8_filepath, const char* u8_mode) {
+		// 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());
 	}
 
 }