doc: update documentation for dialog helper

- fix fwrite fread issue in config manager.
- add testbench for config manager.
- change testbench order to get better experience.

doc/src/config_manager.dox

@@ -0,0 +1,5 @@
+/**
+
+\page config_manager Universal Config Manager
+
+*/

doc/src/dialog_helper.dox

@@ -0,0 +1,78 @@
+/**
+
+\page dialog_helper Dialog Helper
+
+Picking files and folders is an important and essential operation under Windows.
+However the functions picking files and folders are so complex.
+This helper provides universal dialog picker by simple classes and functions.
+In following contents we will tell you how to call them.
+
+This helper is Windows specific.
+It will be totally invisible if you are in other platforms.
+
+\section dialog_helper__file_dialog Configure File Dialog
+
+The first thing is that we should initialize YYCC::DialogHelper::FileDialog, 
+and configure it according to your requirements.
+
+This class is the data struct representing all aspects of file dialog.
+It also one of the arguments in final dialog function.
+
+\code
+YYCC::DialogHelper::FileDialog params;
+params.SetOwner(owner_getter());
+params.SetTitle(YYCC_U8("My File Picker"));
+params.SetInitFileName(YYCC_U8("test.txt"));
+params.SetInitDirectory(initial_directory_getter());
+\endcode
+
+\subsection dialog_helper__file_dialog__owner Owner
+
+YYCC::DialogHelper::FileDialog::SetOwner will set owner of this dialog.
+It accepts a Microsoft defined \c HWND as argument which should be familiar with Windows programmer.
+If you pass \c NULL to it or skip calling this function, it indicate that there is no owner of this dialog.
+<I>
+I don't what whill happend if there is no owner for it.
+But it would be better to have an owner if possible.
+</I>
+
+\subsection dialog_helper__file_dialog__title Title
+
+YYCC::DialogHelper::FileDialog::SetTitle will set dialog title of this dialog.
+If you pass \c nullptr or skip calling it,
+the title of dialog will be filled by system and the function type you calling.
+For example, the title will be "Open..." if you call open file function,
+and will be "Save As..." if you call save file function.
+At the same time, the language of this title filled by system is system UI dependent.
+It means that you do not need to do any extra I18N work for it.
+So I suggest you do not set title except you really want to modify title.
+
+\subsection dialog_helper__file_dialog__init_file_name Initial File Name
+
+YYCC::DialogHelper::FileDialog::SetInitFileName will set the initial file name presented in dialog file name input box.
+If you pass \c nullptr or skip calling it, the text in dialog file name input box will be empty.
+
+User can modify the name presented in input box later.
+But if you assign this value, the dialog will lose the ability that remember the previous name user input in previous calling.
+In normal case, dialog will try remembering the file name user input in dialog, and represent it in the next calling.
+However, if you specify this field, the dialog will always presented your specified value in every calling.
+
+\subsection dialog_helper__file_dialog__init_directory Initial Directory
+
+YYCC::DialogHelper::FileDialog::SetInitDirectory will set the initial directory (startup directory) when opening dialog.
+
+In following cases, initial directory will fall back to system behavior:
+
+\li Pass \c nullptr to this function.
+\li Skip calling this function.
+\li Given directory path is invalid.
+
+The system default behavior of initial directory is similar with initial file name.
+The dialog will try remembering the last directory you just entering, and will back into it in the next calling.
+The directory we meeting in the first launch is system defined.
+
+\section dialog_helper__file_filters Configure File Filters
+
+\section dialog_helper__result Create Dialog and Get Result
+
+*/

doc/src/encoding_helper.dox

@@ -0,0 +1,11 @@
+/**
+
+\page encoding_helper Encoding Helper
+
+YYCC::EncodingHelper namespace include all encoding related functions:
+
+\li The convertion between native string and UTF8 string which has been introduced in chapter \ref library_encoding.
+\li Windows specific convertion between \c WCHAR, UTF8 string and string encoded by other encoding.
+\li The convertion among UTF8, UTF16 and UTF32.
+
+*/

doc/src/index.dox

@@ -1,10 +1,55 @@
 /**
 
-\mainpage YYCCommonplace Library Manual
+\mainpage YYCCommonplace Programming Manual
 
-This manual is organized into the following chapters and appendices:
+<TABLE CELLPADDING="8" CELLSPACING="0" SUMMARY="TITLE BAR" WIDTH="100%" BORDER="0">
+<TR>
+  <TD><CENTER>
+    \image html yycc_icon.png
+  </CENTER></TD>
+  <TD><CENTER>
+    <B>YYCCommonplace Programming Manual</B>
 
-\subpage intro
+    Copyright 2024 by yyc12345.
+  </CENTER></TD>
+</TR>
+</TABLE>
+<TABLE CELLPADDING="8" CELLSPACING="0" SUMMARY="TITLE BAR" WIDTH="100%" BORDER="0">
+<TR>
+  <TD>
+    This software and manual are provided under the terms of the MIT License.
+  </TD>
+</TR>
+</TABLE>
+<TABLE CELLPADDING="8" CELLSPACING="0" SUMMARY="Table of Contents" WIDTH="100%" BORDER="0">
+<TR>
+  <TD ALIGN="LEFT" VALIGN="TOP">
 
+    <B>General Features</B>
+
+    \li \subpage intro
+
+    \li \subpage library_encoding
+
+    \li \subpage encoding_helper
+
+    \li \subpage string_helper
+
+    <B>Advanced Features</B>
+
+    \li \subpage config_manager
+
+  </TD>
+  <TD ALIGN="LEFT" VALIGN="TOP">
+
+    <B>Windows Specific Features</B>
+
+    \li \subpage win_import
+
+    \li \subpage dialog_helper
+
+  </TD>
+</TR>
+</TABLE>
 
 */

doc/src/intro.dox

@@ -2,10 +2,75 @@
 
 \page intro Introduction to YYCCommonplace
 
-work in progress
+YYCCommonplace, or YYC Commonplace (abbr. YYCC), is a static library providing various useful C++ functions when programming with standard library or Windows environment.
 
-\section work in progress
+Actually YYCC provides the functions which I frequently used in my personal projects.
+Thus I do not need copy these functions from one project to another project.
+I can write them once and use them everywhere.
+It's also good for bug fix.
+If I found bug in these code, I only need to fix it in this project.
+Otherwise I need to fix them one by one in each project because they share the same code.
 
-work in progress
+\section intro__why Why YYCCommonplace
+
+\subsection intro__why__windows Windows Issues
+
+I frequently program on Windows environment because the software I programming for, Virtools, is Windows-only software.
+During programming, I found Windows is super lack in UTF8 supports.
+Programmer loves UTF8, because it can handle all charcaters over the world in one encoding and is still compatible with C-Style string.
+However, Windows use a weird way to achieve internationalization, 2 different function trailing, A and W for legacy code and modern code respectively.
+The worst things is that the char type W trailing function used, \c WCHAR, is defined as 2 bytes long, not 4 bytes long as Linux does (\c wchar_t).
+It mean that one emoji charcater will be torn into 2 \c WCHAR on Windows because emoji code unit is higher than the manimum value of \c WCHAR.
+
+Also, there are various issues which should not be presented.
+For example, Microsoft invents various \e safe standard library functions to prevent possible overflow issues raised by \c std::fgets and etc.
+also, MSVC may throw weird error when you using some specific standard library functions.
+You need to define some weird macro to disable this shitty behavior.
+
+There are various non-standard issue you may faced on Windows programming. 
+All in all, programming on Windows is a tough work.
+This is one of the reasons why I create this library.
+I create much wrappers for these weird Windows functions.
+Thus I can have a similar Linux C++ programming experience on Windows.
+
+\subsection intro__why__std Standard Library Issues
+
+The eccentric decision of standard commission also is the reason why I create this library.
+
+\li C++ standard commission loves to bring one feature with N concepts and P assistant classes.
+\li C++ standard commission seems doesn't want to bring any features the programmer urgent needed.
+\li C++ standard commission loves delete programmer loved convenient functions and classes.
+\li etc...
+
+There is not a proper way to \e format a string in C++ until C++ 20 (\c std::format).
+String related functions, such as split, lower, higher, replace, now still not be included in standard library.
+Programmer loved, easy to used UTF8 procession functions and classes was deprecate now and will be removed in future.
+
+That's why I create this library.
+I bring these function in this library.
+Not industrial level, but easy to use and have enough performance in my project.
+
+\subsection intro__why__boost Boost Issues
+
+Bosst is a powerful C++ library. But the shortcoming is overt. It's tooooo big.
+This drawback will be more obvious considering the bad dependency mechanism of C++.
+Although the most of Boost sub-library is header-only, but some library still need to link with Boost.
+It order you download the whole Boost library and extract it in your hard disk.
+Cost more than half hours, 5+ GB disk space and the life time of your disk.
+
+The functions belonging to Boost is industrial level.
+But what I want is not industrial level functions.
+I only need a function which can barely finish my work. That's enough.
+I don't need extreme performance. I just want my code works.
+
+So I create this library, bring some Boost functions with ordinary but not bad implementation.
+
+\section intro__usage Library Usage
+
+Before using this library, I suggest you read this manual fully to have a full overview of this library.
+Otherwise you may make mistake during using this library.
+I suggest you read this manual from top to bottom in the left tree panel, one by one.
+
+This library is a static library.
 
 */

doc/src/library_encoding.dox

@@ -0,0 +1,191 @@
+/**
+
+\page library_encoding Library Encoding
+
+Before using this library, you should know the encoding strategy of this library first.
+In short words, this library use UTF8 encoding everywhere except some special cases,
+for example, function explicitly order the encoding of input parameters.
+
+In following content of this article, you will know the details about how we use UTF8 in this library.
+
+\section library_encoding__utf8_type UTF8 Type
+
+YYCC uses custom UTF8 char type, string container and string view all over the library, from parameters to return value.
+Following content will introduce how we define them.
+
+\subsection library_encoding__utf8_type__char_type Char Type
+
+YYCC library has its own UTF8 char type, \c yycc_char8_t.
+This is how we define it:
+
+\code
+#if defined(__cpp_char8_t)
+using yycc_char8_t = char8_t;
+#else
+using yycc_char8_t = unsigned char;
+#endif
+\endcode
+
+If your environment (higher or equal to C++ 20) supports \c char8_t provided by standard library, \c yycc_char8_t is just an alias to \c char8_t,
+otherwise (lower than C++ 20, e.g. C++ 17), \c yycc_char8_t will be defined as \c unsigned \c char like C++ 20 does (this can be seen as a polyfill).
+
+This means that if you already have used \c char8_t provided by standard library,
+you do not need to do any extra modification before using this library.
+Because all types are compatible.
+
+\subsection library_encoding__utf8_type__container_type String Container and View
+
+We define string container and string view like this:
+
+\code
+using yycc_u8string = std::basic_string<yycc_char8_t>;
+using yycc_u8string_view = std::basic_string_view<yycc_char8_t>;
+\endcode
+
+The real code written in library may be slightly different with this but they have same meanings.
+
+In \c char8_t environment, they are just the alias to \c std::u8string and \c std::u8string_view respectively.
+So if you have already used them, no need to any modification for your code before using this library.
+
+\subsection library_encoding__utf8_type__why Why?
+
+You may curious why I create a new UTF8 char type, rather than using standard library UTF8 char type directly. There are 2 reasons.
+
+First, It was too late that I notice I can use standard library UTF8 char type.
+My UTF8 char type has been used in library everywhere and its tough to fully replace them into standard library UTF8 char type.
+
+Second, UTF8 related content of standard library is \e volatile.
+I notice standard library change UTF8 related functions frequently and its API are not stable.
+For example, standard library brings \c std::codecvt_utf8 in C++ 11, deprecate it in C++ 17 and even remove it in C++ 26.
+That's unacceptable! So I create my own UTF8 type to avoid the scenario that standard library remove \c char8_t in future.
+
+\section library_encoding__utf8_literal UTF8 Literal
+
+String literal is a C++ concept.
+If you are not familar with it, please browse related article first, such as CppReference.
+
+\subsection library_encoding__utf8_literal__single Single Literal
+
+In short words, YYCC allow you declare an UTF8 literal like this:
+
+\code
+YYCC_U8("This is UTF8 literal.")
+\endcode
+
+YYCC_U8 is macro.
+You don't need add extra \c u8 prefix in string given to the macro.
+This macro will do this automatically.
+
+In detail, this macro do a \c reinterpret_cast to change the type of given argument to \c const \c yycc_char8_t* forcely.
+This ensure that declared UTF8 literal is compatible with YYCC UTF8 types.
+
+\subsection library_encoding__utf8_literal__concatenation Literal Concatenation
+
+YYCC_U8 macro also works for string literal concatenation:
+
+\code
+YYCC_U8("Error code: " PRIu32 ". Please contact me.");
+\endcode
+
+According to C++ standard for string literal concatenation, 
+<I>"If one of the strings has an encoding prefix and the other does not, the one that does not will be considered to have the same encoding prefix as the other."</I>
+At the same time, YYCC_U8 macro will automatically add \c u8 prefix for the first component of this string literal concatenation.
+So the whole string will be UTF8 literal.
+It also order you should \b not add any prefix for other components of this string literal concatenation.
+
+\subsection library_encoding__utf8_literal__why Why?
+
+You may know that C++ standard allows programmer declare an UTF8 literal explicitly by writing code like this:
+
+\code
+u8"foo bar"
+\endcode
+
+This is okey. But it may incompatible with YYCC UTF8 char type.
+According to C++ standard, this UTF8 literal syntax will only return \c const \c char8_t* if your C++ standard higher or equal to C++ 20,
+otherwise it will return \c const \c char*.
+This behavior cause that you can not assign this UTF8 literal to \c yycc_u8string if you are in the environment which do not support \c char8_t, 
+because their types are different.
+Thereas you can not use the functions provided by this library because they are all use YYCC defined UTF8 char type.
+
+\section library_encoding__utf8_pointer UTF8 String Pointer
+
+String pointer means the raw pointer pointing to a string, such as \c const \c char*, \c char*, \c char32_t* and etc.
+
+Many legacy code assume \c char* is encoded with UTF8 (the exception is Windows). But \c char* is incompatible with \c yycc_char8_t.
+YYCC provides YYCC::EncodingHelper::ToUTF8 to resolve this issue. There is an exmaple:
+
+\code
+const char* absolutely_is_utf8 = "I confirm this is encoded with UTF8.";
+const yycc_char8_t* converted = YYCC::EncodingHelper::ToUTF8(absolutely_is_utf8);
+
+char* mutable_utf8 = const_cast<char*>(absolutely_is_utf8); // This is not safe. Just for example.
+yycc_char8_t* mutable_converted = YYCC::EncodingHelper::ToUTF8(mutable_utf8);
+\endcode
+
+YYCC::EncodingHelper::ToUTF8 has 2 overloads which can handle const and mutable stirng pointer convertion respectively.
+
+YYCC also has ability that convert YYCC UTF8 char type to native char type by YYCC::EncodingHelper::ToNative.
+Here is an exmaple:
+
+\code
+const yycc_char8_t* yycc_utf8 = YYCC_U8("I am UTF8 string.");
+const char* converted = YYCC::EncodingHelper::ToNative(yycc_utf8);
+
+yycc_char8_t* mutable_yycc_utf8 = const_cast<char*>(yycc_utf8); // Not safe. Also just for example.
+char* mutable_converted = YYCC::EncodingHelper::ToNative(mutable_yycc_utf8);
+\endcode
+
+Same as YYCC::EncodingHelper::ToUTF8, YYCC::EncodingHelper::ToNative also has 2 overloads to handle const and mutable string pointer.
+
+\section library_encoding__utf8_container UTF8 String Container
+
+String container usually means the standard library string container, such as \c std::string, \c std::wstring, \c std::u32string and etc.
+
+In many personal project, programmer may use \c std::string everywhere because \c std::u8string may not be presented when writing peoject.
+How to do convertion between native string container and YYCC UTF8 string container?
+It is definitely illegal that directly do force convertion. Because they may have different class layout.
+Calm down and I will tell you how to do correct convertion.
+YYCC provides YYCC::EncodingHelper::ToUTF8 to convert native string container to YYCC UTF8 string container.
+There is an exmaple:
+
+\code
+std::string native_string("I am UTF8");
+yycc_u8string yycc_string = YYCC::EncodingHelper::ToUTF8(native_string);
+auto result = YYCC::EncodingHelper::UTF8ToUTF32(yycc_string);
+\endcode
+
+Actually, YYCC::EncodingHelper::ToUTF8 accepts a reference to \c std::string_view as argument.
+However, there is a implicit convertion from \c std::string to \c std::string_view, 
+so you can directly pass a \c std::string instance to it.
+
+String view will reduce unnecessary memory copy.
+If you just want to pass native string container to function, and this function accepts \c yycc_u8string_view as its argument,
+you can use alternative YYCC::EncodingHelper::ToUTF8View.
+
+\code
+std::string native_string("I am UTF8");
+yycc_u8string_view yycc_string = YYCC::EncodingHelper::ToUTF8View(native_string);
+auto result = YYCC::EncodingHelper::UTF8ToUTF32(yycc_string);
+\endcode
+
+Comparing with previous one, this example use less memory.
+The reduced memory is the content of \c yycc_string because string view is a view, not the copy of original string.
+
+Same as UTF8 string pointer, we also have YYCC::EncodingHelper::ToNative and YYCC::EncodingHelper::ToNativeView do correspondant reverse convertion.
+Try to do your own research and figure out how to use them.
+It's pretty easy.
+
+\section library_encoding__windows Warnings to Windows Programmer
+
+Due to the legacy of MSVC, the encoding of \c char* may not be UTF8 in most cases.
+If you run the convertion code introduced in this article with the string which is not encoded with UTF8, it may cause undefined behavior.
+
+To enable UTF8 mode of MSVC, please deliver \c /utf-8 switch to MSVC.
+Thus you can use the functions introduced in this article safely.
+Otherwise, you must guarteen that the argument you provided to these functions is encoded by UTF8 manually.
+
+Linux user do not need care this.
+Because almost Linux distro use UTF8 in default.
+
+*/

doc/src/string_helper.dox

@@ -0,0 +1,43 @@
+/**
+
+\page string_helper String Helper
+
+
+\section string_helper_lower_upper Lower Upper
+
+String helper provides Python-like string lower and upper function.
+Both lower and upper function have 2 overloads:
+
+\code
+yycc_u8string Lower(const yycc_char8_t*);
+void Lower(yycc_u8string&);
+\endcode
+
+First overload accepts a NULL-terminated string as argument and return a \b copy whose content are all the lower case of original string.
+Second overload accepts a mutable string container as argument and will make all characters stored in it become their lower case.
+You can choose on of them for your flavor and requirements.
+Upper also has similar 2 overloads.
+
+\section string_helper_split Split
+
+String helper provides Python-like string split function.
+It has 2 types for you:
+
+\code
+std::vector<yycc_u8string> Split(const yycc_u8string_view&, const yycc_char8_t*);
+std::vector<yycc_u8string_view> SplitView(const yycc_u8string_view&, const yycc_char8_t*);
+\endcode
+
+All these overloads take a string view as the first argument for the string need to be split.
+The second argument is a raw string pointer representing the decilmer for splitting.
+The only difference between these 2 split function are overt according to their names.
+The first split function will return a list of copied string as its split result.
+The second split function will return a list of string view as its split result,
+and it will keep valid as long as the life time of your given string view argument.
+It also means that the last type will cost less memory if you don't need the copy of original string.
+
+If the source string (the string need to be split) is empty, or the decilmer is \c nullptr or empty,
+the result will only has 1 item and this item is source string itself.
+There is no way that this method return an empty list, except the code is buggy.
+
+*/

doc/src/win_import.dox

@@ -0,0 +1,69 @@
+/**
+
+\page win_import Windows Import Guard
+
+Windows is shitty for the programmer who is familiar with UNIX programming.
+Due to legacy reason, Windows defines various things which are not compatible with UNIX or standard C++ programming.
+
+\section win_import__usage Usage
+
+YYCC has a way to solve the issue introduced above.
+
+\code
+#if YYCC_OS == YYCC_OS_WINDOWS
+#include <WinImportPrefix.hpp>
+#include <Windows.h>
+#include "other_header_depend_on_windows.h"
+#include <WinImportSuffix.hpp>
+#endif
+\endcode
+
+The including of WinImportPrefix.hpp and WinImportSuffix.hpp is a pair.
+They just like a guard bracket the include operation of Windows related headers,
+to keep all Windows shitty contents will not be leaked outside.
+
+This guard can solve following issues:
+
+<UL>
+    <LI>
+    Programmer can not use \c std::max and \c std::min normally.
+    <UL>
+        <LI>Windows defines \c MAX and \c MIN as macros for personal use. This is why this happend.</LI>
+        <LI>Guard defines some special macros to tell Windows do not create these 2 macros.</LI>
+    </UL>
+    </LI>
+    <LI>
+    Programmer will not be affected by the automatical rename of \c GetObject, \c GetClassName and etc.
+    <UL>
+        <LI>These are all macros for Windows personal use to automatically redirect calling to A function and W function by compiling environment.</LI>
+        <LI>Guard \c #undef these annoy macros.</LI>
+    </UL>
+    </LI>
+    <LI>
+    Compiler throw annoy warnings and errors when using specific standard library functions.
+    <UL>
+        <LI>MSVC will throw warnings and errors when you are using Microsoft so-called \e depracted or \e unsafe standard library functions.</LI>
+        <LI>YYCCInternal.hpp, which has been included by this pair, defines some macros to purge these warnings and errors out.</LI>
+    </UL>
+    </LI>
+</UL>
+
+\section win_import__notes Notes
+
+If you have other header files which are strongly depend on Windows header,
+you should put them into this bracket at the same time like example did.
+Because this guard operate some Windows macros as we introduced above.
+The headers depending on Windows may throw error if you put them outside of this pair.
+
+Please note WinImportPrefix.hpp and WinImportSuffix.hpp can be included multiple times.
+Because they do not have the proprocessor command like <I>#pragma once</I> or etc to make sure they only can be included once.
+That's by design. Because we actually may use this pair multiple times.
+The only thing you should pledge is that you must make sure they are presented by pair.
+
+This guard is Windows specific.
+It does nothing if you accidently use it in other platforms such as Linux,
+because the headers use \c #if to check environment out and will do nothing in non-Windows environment.
+However, we still highly recommend you use this pair with platform checker bracket like example does,
+if your program need to be run on multiple platforms.
+
+*/

src/CMakeLists.txt

@@ -5,6 +5,7 @@ target_sources(YYCCommonplace
 PRIVATE
     # Sources
     COMHelper.cpp
+    ConfigManager.cpp
     ConsoleHelper.cpp
     DialogHelper.cpp
     EncodingHelper.cpp
@@ -21,6 +22,7 @@ FILES
     # Headers
     # Common headers
     COMHelper.hpp
+    ConfigManager.hpp
     ConsoleHelper.hpp
     DialogHelper.hpp
     EncodingHelper.hpp

src/ConfigManager.cpp

@@ -0,0 +1,148 @@
+#include "ConfigManager.hpp"
+
+#include "EncodingHelper.hpp"
+#include "IOHelper.hpp"
+
+namespace YYCC::ConfigManager {
+
+#pragma region Core Manager
+
+	CoreManager::CoreManager(
+		const yycc_char8_t* cfg_file_path,
+		uint64_t version_identifier,
+		std::initializer_list<AbstractSetting*> settings) :
+		m_CfgFilePath(), m_VersionIdentifier(version_identifier), m_Settings() {
+		// assign cfg path
+		if (cfg_file_path != nullptr)
+			m_CfgFilePath = cfg_file_path;
+		// assign settings
+		for (auto* setting : settings) {
+			m_Settings.try_emplace(setting->GetName(), setting);
+		}
+	}
+
+	bool CoreManager::Load() {
+		// reset all settings first
+		Reset();
+
+		// get file handle
+		auto fs = this->GetFileHandle(YYCC_U8("rb"));
+		if (fs.get() == nullptr) {
+			// if we fail to get, it means that we do not have corresponding cfg file.
+			// all settings should be reset to default value.
+			return true;
+		}
+
+		// fetch version info
+		uint64_t version_info;
+		if (std::fread(&version_info, 1u, sizeof(version_info), fs.get()) != sizeof(version_info))
+			return false;
+		// check version
+		// if read version is greater than we expected,
+		// it means that this cfg file is created by the program higer than this.
+		// we should not read anything from it.
+		// however, for compaitibility reason, we allow read old cfg data.
+		if (version_info > m_VersionIdentifier)
+			return true;
+
+		// fetch setting item from file
+		yycc_u8string name_cache;
+		while (true) {
+			// try fetch setting name
+			// fetch name length
+			size_t name_length;
+			if (std::fread(&name_length, 1u, sizeof(name_length), fs.get()) != sizeof(name_length)) {
+				// we also check whether reach EOF at there.
+				if (std::feof(fs.get())) break;
+				else return false;
+			}
+			// fetch name body
+			name_cache.resize(name_length);
+			if (std::fread(name_cache.data(), 1u, name_length, fs.get()) != name_length)
+				return false;
+
+			// get setting data length
+			size_t data_length;
+			if (std::fread(&data_length, 1u, sizeof(data_length), fs.get()) != sizeof(data_length))
+				return false;
+
+			// get matched setting first
+			const auto& found = m_Settings.find(name_cache);
+			if (found != m_Settings.end()) {
+				// found. read data for it
+				found->second->ResizeData(data_length);
+				if (std::fread(found->second->GetDataPtr(), 1u, data_length, fs.get()) != data_length)
+					return false;
+				// call user defined load function
+				// if fail to parse, reset to default value
+				if (!found->second->UserLoad())
+					found->second->UserReset();
+			} else {
+				// fail to find. skip this unknown setting
+				if (fseek(fs.get(), static_cast<long>(data_length), SEEK_CUR) != 0)
+					return false;
+			}
+		}
+
+		return true;
+	}
+
+	bool CoreManager::Save() {
+		// get file handle
+		auto fs = this->GetFileHandle(YYCC_U8("wb"));
+		// if we fail to get, return false.
+		if (fs == nullptr) return false;
+
+		// write config data
+		uint64_t version_info = m_VersionIdentifier;
+		if (std::fwrite(&version_info, 1u, sizeof(version_info), fs.get()) != sizeof(version_info))
+			return false;
+
+		// iterate all data for writing
+		for (const auto& pair : m_Settings) {
+			// do user defined save
+			// if failed, skip this setting
+			if (!pair.second->UserSave())
+				continue;
+
+			// write setting name
+			// write name length
+			size_t name_length = pair.first.size();
+			if (std::fwrite(&name_length, 1u, sizeof(name_length), fs.get()) != sizeof(name_length))
+				return false;
+			// write name body
+			if (std::fwrite(pair.first.c_str(), 1u, name_length, fs.get()) != name_length)
+				return false;
+
+			// write setting daat
+			// write data length
+			size_t data_length = pair.second->GetDataSize();
+			if (std::fwrite(&data_length, 1u, sizeof(data_length), fs.get()) != sizeof(data_length))
+				return false;
+			// write data body
+			if (std::fwrite(pair.second->GetDataPtr(), 1u, data_length, fs.get()) != data_length)
+				return false;
+		}
+
+		// all settings done, return true
+		return true;
+	}
+
+	void CoreManager::Reset() {
+		for (const auto& pair : m_Settings) {
+			pair.second->UserReset();
+		}
+	}
+
+	CoreManager::FileHandleGuard_t CoreManager::GetFileHandle(const yycc_char8_t* mode) const {
+		return CoreManager::FileHandleGuard_t(
+			IOHelper::UTF8FOpen(this->m_CfgFilePath.c_str(), mode),
+			[](FILE* fs) -> void {
+				if (fs != nullptr) std::fclose(fs);
+			}
+		);
+	}
+
+#pragma endregion
+
+}

src/ConfigManager.hpp

@@ -0,0 +1,203 @@
+#pragma once
+#include "YYCCInternal.hpp"
+
+#include <memory>
+#include <vector>
+#include <map>
+#include <initializer_list>
+#include <type_traits>
+#include <algorithm>
+#include <functional>
+#include <stdexcept>
+
+namespace YYCC::ConfigManager {
+
+	template<typename _Ty>
+	struct Constrain {
+		using CheckFct_t = std::function<bool(const _Ty&)>;
+		//using CorrectFct_t = std::function<_Ty(const _Ty&)>;
+		CheckFct_t m_CheckFct;
+		//CorrectFct_t m_CorrectFct;
+
+		bool IsValid() const {
+			return m_CheckFct != nullptr/* && m_CorrectFct != nullptr*/;
+		}
+	};
+
+	namespace ConstrainPresets {
+
+		template<typename _Ty, std::enable_if_t<std::is_arithmetic_v<_Ty> && !std::is_enum_v<_Ty> && !std::is_same_v<_Ty, bool>, int> = 0>
+		Constrain<_Ty> GetNumberRangeConstrain(_Ty min_value, _Ty max_value) {
+			if (min_value > max_value)
+				throw std::invalid_argument("invalid min max value for NumberRangeConstrain");
+			return Constrain<_Ty> {
+				[min_value, max_value](const _Ty& val) -> bool { return (val <= max_value) && (val >= min_value); }
+					/*[min_value, max_value](const _Ty& val) -> _Ty { return std::clamp(val, min_value, max_value); }*/
+			};
+		}
+
+	}
+
+	class AbstractSetting {
+		friend class CoreManager;
+	public:
+		AbstractSetting(const yycc_char8_t* name) : m_Name(), m_RawData() {
+			if (name != nullptr) m_Name = name;
+		}
+		virtual ~AbstractSetting() {}
+
+		// Name interface
+	public:
+		const yycc_u8string& GetName() const { return m_Name; }
+	private:
+		yycc_u8string m_Name;
+
+		// User Implementations
+	protected:
+		virtual bool UserLoad() = 0;
+		virtual bool UserSave() = 0;
+		virtual void UserReset() = 0;
+
+		// Buffer related functions
+	protected:
+		void ResizeData(size_t new_size) { m_RawData.resize(new_size); }
+		const void* GetDataPtr() const { return m_RawData.data(); }
+		void* GetDataPtr() { return m_RawData.data(); }
+		size_t GetDataSize() const { return m_RawData.size(); }
+	private:
+		std::vector<uint8_t> m_RawData;
+	};
+
+	class CoreManager {
+	public:
+		CoreManager(
+			const yycc_char8_t* cfg_file_path,
+			uint64_t version_identifier,
+			std::initializer_list<AbstractSetting*> settings);
+		~CoreManager() {}
+
+		// Core functions
+	public:
+		bool Load();
+		bool Save();
+		void Reset();
+
+	private:
+		using FileHandleGuard_t = std::unique_ptr<FILE, std::function<void(FILE*)>>;
+		FileHandleGuard_t GetFileHandle(const yycc_char8_t* mode) const;
+
+		yycc_u8string m_CfgFilePath;
+		uint64_t m_VersionIdentifier;
+		std::map<yycc_u8string, AbstractSetting*> m_Settings;
+	};
+
+#pragma region Setting Presets
+
+	template<typename _Ty, std::enable_if_t<std::is_arithmetic_v<_Ty> || std::is_enum_v<_Ty>, int> = 0>
+	class NumberSetting : public AbstractSetting {
+	public:
+		NumberSetting(const yycc_char8_t* name, _Ty default_value, Constrain<_Ty> constrain = Constrain<_Ty> {}) :
+			AbstractSetting(name), m_Data(default_value), m_DefaultData(default_value), m_Constrain(constrain) {}
+		virtual ~NumberSetting() {}
+
+		_Ty Get() const { return m_Data; }
+		bool Set(_Ty new_data) { 
+			// validate data
+			if (m_Constrain.IsValid() && !m_Constrain.m_CheckFct(new_data))
+				return false;
+			// assign data
+			m_Data = new_data;
+			return true;
+		}
+
+	protected:
+		virtual bool UserLoad() override {
+			// read data
+			if (sizeof(m_Data) != GetDataSize())
+				return false;
+			m_Data = *reinterpret_cast<const _Ty*>(GetDataPtr());
+			// check data
+			if (m_Constrain.IsValid() && !m_Constrain.m_CheckFct(m_Data))
+				return false;
+			return true;
+		}
+		virtual bool UserSave() override {
+			// write data
+			ResizeData(sizeof(m_Data));
+			*reinterpret_cast<_Ty*>(GetDataPtr()) = m_Data;
+			return true;
+		}
+		virtual void UserReset() override {
+			m_Data = m_DefaultData;
+		}
+
+		_Ty m_Data, m_DefaultData;
+		Constrain<_Ty> m_Constrain;
+	};
+
+	class StringSetting : public AbstractSetting {
+	public:
+		StringSetting(const yycc_char8_t* name, const yycc_char8_t* default_value, Constrain<yycc_u8string> constrain = Constrain<yycc_u8string> {}) :
+			AbstractSetting(name), m_Data(), m_DefaultData(), m_Constrain(constrain) {
+			if (default_value != nullptr) {
+				m_Data = default_value;
+				m_DefaultData = default_value;
+			}
+		}
+		virtual ~StringSetting() {}
+
+		const yycc_u8string& Get() const { return m_Data; }
+		bool Set(const yycc_char8_t* new_data) {
+			// check data validation
+			if (new_data == nullptr) 
+				return false;
+			if (m_Constrain.IsValid() && !m_Constrain.m_CheckFct(m_Data))
+				return false;
+			// assign data
+			m_Data = new_data;
+			return true;
+		}
+
+	protected:
+		virtual bool UserLoad() override {
+			// read string length
+			size_t string_length;
+			if (GetDataSize() < sizeof(string_length))
+				return false;
+			string_length = *reinterpret_cast<const size_t*>(GetDataPtr());
+			// read string body
+			if (GetDataSize() != sizeof(string_length) + string_length)
+				return false;
+			m_Data.assign(
+				reinterpret_cast<const yycc_char8_t*>(static_cast<const uint8_t*>(GetDataPtr()) + sizeof(string_length)),
+				string_length
+			);
+			// check data
+			if (m_Constrain.IsValid() && !m_Constrain.m_CheckFct(m_Data))
+				return false;
+			return true;
+		}
+		virtual bool UserSave() override {
+			// allocate result buffer
+			size_t string_length = m_Data.size();
+			ResizeData(sizeof(string_length) + string_length);
+			// get pointer
+			uint8_t* ptr = static_cast<uint8_t*>(GetDataPtr());
+			// assign string length
+			*reinterpret_cast<size_t*>(ptr) = string_length;
+			// assign string body
+			std::memcpy(ptr + sizeof(string_length), m_Data.data(), string_length);
+			return true;
+		}
+		virtual void UserReset() override {
+			m_Data = m_DefaultData;
+		}
+
+		yycc_u8string m_Data, m_DefaultData;
+		Constrain<yycc_u8string> m_Constrain;
+	};
+
+#pragma endregion
+
+
+}

src/ConsoleHelper.cpp

@@ -54,7 +54,7 @@ namespace YYCC::ConsoleHelper {
 	*/
 
 	template<bool _bIsConsole>
-	static std::string WinConsoleRead(HANDLE hStdIn) {
+	static yycc_u8string WinConsoleRead(HANDLE hStdIn) {
 		using _TChar = std::conditional_t<_bIsConsole, wchar_t, char>;
 
 		// Prepare an internal buffer because the read data may not be fully used.
@@ -113,21 +113,21 @@ namespace YYCC::ConsoleHelper {
 		}
 
 		// post-process for return value
-		std::string real_return_buffer;
+		yycc_u8string real_return_buffer;
 		if constexpr (_bIsConsole) {
 			// console mode need convert wchar to utf8
-			YYCC::EncodingHelper::WcharToUTF8(return_buffer.c_str(), real_return_buffer);
+			YYCC::EncodingHelper::WcharToUTF8(return_buffer, real_return_buffer);
 		} else {
 			// non-console just copt the result
-			real_return_buffer = return_buffer;
+			real_return_buffer = EncodingHelper::ToUTF8(return_buffer);
 		}
 		// every mode need delete \r words
-		YYCC::StringHelper::Replace(real_return_buffer, "\r", "");
+		YYCC::StringHelper::Replace(real_return_buffer, YYCC_U8("\r"), YYCC_U8(""));
 		// return value
 		return real_return_buffer;
 	}
 
-	static void WinConsoleWrite(const std::string& strl, bool to_stderr) {
+	static void WinConsoleWrite(const yycc_u8string& strl, bool to_stderr) {
 		// Prepare some Win32 variables
 		// fetch stdout handle first
 		HANDLE hStdOut = GetStdHandle(to_stderr ? STD_ERROR_HANDLE : STD_OUTPUT_HANDLE);
@@ -139,7 +139,7 @@ namespace YYCC::ConsoleHelper {
 		if (GetConsoleMode(hStdOut, &dwConsoleMode)) {
 			// console handle, use WriteConsoleW.
 			// convert utf8 string to wide char first
-			std::wstring wstrl(YYCC::EncodingHelper::UTF8ToWchar(strl.c_str()));
+			std::wstring wstrl(YYCC::EncodingHelper::UTF8ToWchar(strl));
 			size_t wstrl_size = wstrl.size();
 			// write string with size check
 			if (wstrl_size <= std::numeric_limits<DWORD>::max()) {
@@ -149,7 +149,7 @@ namespace YYCC::ConsoleHelper {
 			// anything else, use WriteFile instead.
 			// WriteFile do not need extra convertion, because it is direct writing.
 			// check whether string length is overflow
-			size_t strl_size = strl.size() * sizeof(std::string::value_type);
+			size_t strl_size = strl.size() * sizeof(yycc_u8string::value_type);
 			// write string with size check
 			if (strl_size <= std::numeric_limits<DWORD>::max()) {
 				WriteFile(hStdOut, strl.c_str(), static_cast<DWORD>(strl_size), &dwWrittenNumberOfChars, NULL);
@@ -176,7 +176,7 @@ namespace YYCC::ConsoleHelper {
 #endif
 	}
 
-	std::string ReadLine() {
+	yycc_u8string ReadLine() {
 #if YYCC_OS == YYCC_OS_WINDOWS
 
 		// get stdin mode
@@ -188,24 +188,24 @@ namespace YYCC::ConsoleHelper {
 		} else {
 			return WinConsoleRead<false>(hStdIn);
 		}
-
+		
 #else
 
 		// in linux, directly use C++ function to fetch.
 		std::string cmd;
 		if (std::getline(std::cin, cmd).fail()) cmd.clear();
-		return cmd;
+		return EncodingHelper::ToUTF8(cmd);
 
 #endif
 	}
 
 	template<bool bNeedFmt, bool bIsErr, bool bHasEOL>
-	static void RawWrite(const char* u8_fmt, va_list argptr) {
+	static void RawWrite(const yycc_char8_t* u8_fmt, va_list argptr) {
 		// Buiild string need to be written first
 		// If no format string or plain string for writing, return.
 		if (u8_fmt == nullptr) return;
 		// Build or simply copy string
-		std::string strl;
+		yycc_u8string strl;
 		if constexpr (bNeedFmt) {
 			// treat as format string
 			va_list argcpy;
@@ -218,62 +218,62 @@ namespace YYCC::ConsoleHelper {
 		}
 		// Checkout whether add EOL
 		if constexpr (bHasEOL) {
-			strl += "\n";
+			strl += YYCC_U8("\n");
 		}
-
+		
 #if YYCC_OS == YYCC_OS_WINDOWS
 		// call Windows specific writer
 		WinConsoleWrite(strl, bIsErr);
 #else
 		// in linux, directly use C function to write.
-		std::fputs(strl.c_str(), bIsErr ? stderr : stdout);
+		std::fputs(EncodingHelper::ToNative(strl.c_str()), bIsErr ? stderr : stdout);
 #endif
 	}
 
-	void Format(const char* u8_fmt, ...) {
+	void Format(const yycc_char8_t* u8_fmt, ...) {
 		va_list argptr;
 		va_start(argptr, u8_fmt);
 		RawWrite<true, false, false>(u8_fmt, argptr);
 		va_end(argptr);
 	}
 
-	void FormatLine(const char* u8_fmt, ...) {
+	void FormatLine(const yycc_char8_t* u8_fmt, ...) {
 		va_list argptr;
 		va_start(argptr, u8_fmt);
 		RawWrite<true, false, true>(u8_fmt, argptr);
 		va_end(argptr);
 	}
 
-	void Write(const char* u8_strl) {
+	void Write(const yycc_char8_t* u8_strl) {
 		va_list empty{};
 		RawWrite<false, false, false>(u8_strl, empty);
 	}
 	
-	void WriteLine(const char* u8_strl) {
+	void WriteLine(const yycc_char8_t* u8_strl) {
 		va_list empty{};
 		RawWrite<false, false, true>(u8_strl, empty);
 	}
 	
-	void ErrFormat(const char* u8_fmt, ...) {
+	void ErrFormat(const yycc_char8_t* u8_fmt, ...) {
 		va_list argptr;
 		va_start(argptr, u8_fmt);
 		RawWrite<true, true, false>(u8_fmt, argptr);
 		va_end(argptr);
 	}
 
-	void ErrFormatLine(const char* u8_fmt, ...) {
+	void ErrFormatLine(const yycc_char8_t* u8_fmt, ...) {
 		va_list argptr;
 		va_start(argptr, u8_fmt);
 		RawWrite<true, true, true>(u8_fmt, argptr);
 		va_end(argptr);
 	}
 
-	void ErrWrite(const char* u8_strl) {
+	void ErrWrite(const yycc_char8_t* u8_strl) {
 		va_list empty{};
 		RawWrite<false, true, false>(u8_strl, empty);
 	}
 	
-	void ErrWriteLine(const char* u8_strl) {
+	void ErrWriteLine(const yycc_char8_t* u8_strl) {
 		va_list empty{};
 		RawWrite<false, true, true>(u8_strl, empty);
 	}

src/ConsoleHelper.hpp

@@ -124,52 +124,52 @@ namespace YYCC::ConsoleHelper {
 	 * This function also can be used as ordering user press Enter key by
 	 * simply calling this function and ignoring its return value.
 	*/
-	std::string ReadLine();
+	yycc_u8string ReadLine();
 
 	/**
 	 * @brief Universal console write function with format feature.
 	 * @param[in] u8_fmt The format string.
 	 * @param[in] ... The arguments to be formatted.
 	*/
-	void Format(const char* u8_fmt, ...);
+	void Format(const yycc_char8_t* u8_fmt, ...);
 	/**
 	 * @brief Universal console write function with format and auto EOL feature.
 	 * @param[in] u8_fmt The format string.
 	 * @param[in] ... The arguments to be formatted.
 	*/
-	void FormatLine(const char* u8_fmt, ...);
+	void FormatLine(const yycc_char8_t* u8_fmt, ...);
 	/**
 	 * @brief Universal console write function.
 	 * @param[in] u8_strl The string to be written.
 	*/
-	void Write(const char* u8_strl);
+	void Write(const yycc_char8_t* u8_strl);
 	/**
 	 * @brief Universal console write function with auto EOL feature.
 	 * @param[in] u8_strl The string to be written.
 	*/
-	void WriteLine(const char* u8_strl);
+	void WriteLine(const yycc_char8_t* u8_strl);
 
 	/**
 	 * @brief Universal console error write function with format and feature.
 	 * @param[in] u8_fmt The format string.
 	 * @param[in] ... The arguments to be formatted.
 	*/
-	void ErrFormat(const char* u8_fmt, ...);
+	void ErrFormat(const yycc_char8_t* u8_fmt, ...);
 	/**
 	 * @brief Universal console error write function with format and auto EOL feature.
 	 * @param[in] u8_fmt The format string.
 	 * @param[in] ... The arguments to be formatted.
 	*/
-	void ErrFormatLine(const char* u8_fmt, ...);
+	void ErrFormatLine(const yycc_char8_t* u8_fmt, ...);
 	/**
 	 * @brief Universal console error write function.
 	 * @param[in] u8_strl The string to be written.
 	*/
-	void ErrWrite(const char* u8_strl);
+	void ErrWrite(const yycc_char8_t* u8_strl);
 	/**
 	 * @brief Universal console error write function with auto EOL feature.
 	 * @param[in] u8_strl The string to be written.
 	*/
-	void ErrWriteLine(const char* u8_strl);
+	void ErrWriteLine(const yycc_char8_t* u8_strl);
 
 }

src/DialogHelper.cpp

@@ -8,16 +8,16 @@ namespace YYCC::DialogHelper {
 
 #pragma region FileFilters
 
-	bool FileFilters::Add(const char* filter_name, std::initializer_list<const char*> il) {
+	bool FileFilters::Add(const yycc_char8_t* filter_name, std::initializer_list<const yycc_char8_t*> il) {
 		// assign filter name
 		if (filter_name == nullptr) return false;
 		FilterName name(filter_name);
 
 		// assign filter patterns
 		FilterModes modes;
-		for (const char* pattern : il) {
+		for (const yycc_char8_t* pattern : il) {
 			if (pattern != nullptr)
-				modes.emplace_back(std::string(pattern));
+				modes.emplace_back(yycc_u8string(pattern));
 		}
 
 		// check filter patterns
@@ -36,13 +36,13 @@ namespace YYCC::DialogHelper {
 		for (const auto& it : m_Filters) {
 			// convert name to wchar
 			WinFileFilters::WinFilterName name;
-			if (!YYCC::EncodingHelper::UTF8ToWchar(it.first.c_str(), name))
+			if (!YYCC::EncodingHelper::UTF8ToWchar(it.first, name))
 				return false;
 
 			// convert pattern and join them
-			std::string joined_modes(YYCC::StringHelper::Join(it.second, ";"));
+			yycc_u8string joined_modes(YYCC::StringHelper::Join(it.second, YYCC_U8(";")));
 			WinFileFilters::WinFilterModes modes;
-			if (!YYCC::EncodingHelper::UTF8ToWchar(joined_modes.c_str(), modes))
+			if (!YYCC::EncodingHelper::UTF8ToWchar(joined_modes, modes))
 				return false;
 
 			// append new pair
@@ -94,12 +94,12 @@ namespace YYCC::DialogHelper {
 
 		// build title and init file name
 		if (m_HasTitle) {
-			if (!YYCC::EncodingHelper::UTF8ToWchar(m_Title.c_str(), win_result.m_WinTitle))
+			if (!YYCC::EncodingHelper::UTF8ToWchar(m_Title, win_result.m_WinTitle))
 				return false;
 			win_result.m_HasTitle = true;
 		}
 		if (m_HasInitFileName) {
-			if (!YYCC::EncodingHelper::UTF8ToWchar(m_InitFileName.c_str(), win_result.m_WinInitFileName))
+			if (!YYCC::EncodingHelper::UTF8ToWchar(m_InitFileName, win_result.m_WinInitFileName))
 				return false;
 			win_result.m_HasInitFileName = true;
 		}
@@ -108,7 +108,7 @@ namespace YYCC::DialogHelper {
 		if (m_HasInitDirectory) {
 			// convert to wpath
 			std::wstring w_init_directory;
-			if (!YYCC::EncodingHelper::UTF8ToWchar(m_InitDirectory.c_str(), w_init_directory))
+			if (!YYCC::EncodingHelper::UTF8ToWchar(m_InitDirectory, w_init_directory))
 				return false;
 
 			// fetch IShellItem*
@@ -143,7 +143,7 @@ namespace YYCC::DialogHelper {
 	 * @return True if success, otherwise false.
 	 * @remarks This is an assist function of CommonFileDialog.
 	*/
-	static bool ExtractDisplayName(IShellItem* item, std::string& ret) {
+	static bool ExtractDisplayName(IShellItem* item, yycc_u8string& ret) {
 		// fetch display name from IShellItem*
 		LPWSTR _name;
 		HRESULT hr = item->GetDisplayName(SIGDN_FILESYSPATH, &_name);
@@ -168,7 +168,7 @@ namespace YYCC::DialogHelper {
 	 * @remarks This function is the real underlying function of all dialog functions.
 	*/
 	template<CommonFileDialogType EDialogType>
-	static bool CommonFileDialog(const FileDialog& params, std::vector<std::string>& ret) {
+	static bool CommonFileDialog(const FileDialog& params, std::vector<yycc_u8string>& ret) {
 		// Reference: https://learn.microsoft.com/en-us/windows/win32/shell/common-file-dialog
 		// prepare result variable
 		HRESULT hr;
@@ -289,7 +289,7 @@ namespace YYCC::DialogHelper {
 				COMHelper::SmartIShellItem result_item(_item);
 
 				// extract display name
-				std::string result_name;
+				yycc_u8string result_name;
 				if (!ExtractDisplayName(result_item.get(), result_name))
 					return false;
 
@@ -326,7 +326,7 @@ namespace YYCC::DialogHelper {
 					COMHelper::SmartIShellItem result_item(_item);
 
 					// extract display name
-					std::string result_name;
+					yycc_u8string result_name;
 					if (!ExtractDisplayName(result_item.get(), result_name))
 						return false;
 
@@ -347,24 +347,24 @@ namespace YYCC::DialogHelper {
 
 #pragma region Wrapper Functions
 
-	bool OpenFileDialog(const FileDialog& params, std::string& ret) {
-		std::vector<std::string> cache;
+	bool OpenFileDialog(const FileDialog& params, yycc_u8string& ret) {
+		std::vector<yycc_u8string> cache;
 		bool isok = CommonFileDialog<CommonFileDialogType::OpenFile>(params, cache);
 		if (isok) ret = cache.front();
 		return isok;
 	}
-	bool OpenMultipleFileDialog(const FileDialog& params, std::vector<std::string>& ret) {
+	bool OpenMultipleFileDialog(const FileDialog& params, std::vector<yycc_u8string>& ret) {
 		return CommonFileDialog<CommonFileDialogType::OpenMultipleFiles>(params, ret);
 	}
-	bool SaveFileDialog(const FileDialog& params, std::string& ret) {
-		std::vector<std::string> cache;
+	bool SaveFileDialog(const FileDialog& params, yycc_u8string& ret) {
+		std::vector<yycc_u8string> cache;
 		bool isok = CommonFileDialog<CommonFileDialogType::SaveFile>(params, cache);
 		if (isok) ret = cache.front();
 		return isok;
 	}
 
-	bool OpenFolderDialog(const FileDialog& params, std::string& ret) {
-		std::vector<std::string> cache;
+	bool OpenFolderDialog(const FileDialog& params, yycc_u8string& ret) {
+		std::vector<yycc_u8string> cache;
 		bool isok = CommonFileDialog<CommonFileDialogType::OpenFolder>(params, cache);
 		if (isok) ret = cache.front();
 		return isok;

src/DialogHelper.hpp

@@ -58,14 +58,14 @@ namespace YYCC::DialogHelper {
 		 * @brief Add a filter pair in file types list.
 		 * @param filter_name[in] The friendly name of the filter.
 		 * @param il[in] A C++ initialize list.
-		 * Every entries must be `const char*` represent a single filter pattern.
+		 * Every entries must be `const yycc_char8_t*` represent a single filter pattern.
 		 * The list at least should have one valid pattern.
 		 * This function will not validate these filter patterns, so please write them carefully.
 		 * @return True if added success, otherwise false.
 		 * @remarks This function allow you register multiple filter patterns for single friendly name.
 		 * For example: `Add("Microsoft Word (*.doc; *.docx)", {"*.doc", "*.docx"})`
 		*/
-		bool Add(const char* filter_name, std::initializer_list<const char*> il);
+		bool Add(const yycc_char8_t* filter_name, std::initializer_list<const yycc_char8_t*> il);
 		/**
 		 * @brief Clear filter pairs for following re-use.
 		*/
@@ -85,8 +85,8 @@ namespace YYCC::DialogHelper {
 		bool Generate(WinFileFilters& win_result) const;
 
 	protected:
-		using FilterModes = std::vector<std::string>;
-		using FilterName = std::string;
+		using FilterModes = std::vector<yycc_u8string>;
+		using FilterName = yycc_u8string;
 		using FilterPair = std::pair<FilterName, FilterModes>;
 
 		std::vector<FilterPair> m_Filters;
@@ -159,7 +159,7 @@ namespace YYCC::DialogHelper {
 			m_HasTitle(false), m_HasInitFileName(false), m_HasInitDirectory(false) {}
 
 		void SetOwner(HWND owner) { m_Owner = owner; }
-		void SetTitle(const char* title) {
+		void SetTitle(const yycc_char8_t* title) {
 			if (m_HasTitle = title != nullptr)
 				m_Title = title;
 		}
@@ -167,11 +167,11 @@ namespace YYCC::DialogHelper {
 			return m_FileTypes;
 		}
 		void SetDefaultFileTypeIndex(size_t idx) { m_DefaultFileTypeIndex = idx; }
-		void SetInitFileName(const char* init_filename) {
+		void SetInitFileName(const yycc_char8_t* init_filename) {
 			if (m_HasInitFileName = init_filename != nullptr)
 				m_InitFileName = init_filename;
 		}
-		void SetInitDirectory(const char* init_dir) {
+		void SetInitDirectory(const yycc_char8_t* init_dir) {
 			if (m_HasInitDirectory = init_dir != nullptr)
 				m_InitDirectory = init_dir;
 		}
@@ -200,7 +200,7 @@ namespace YYCC::DialogHelper {
 	protected:
 		HWND m_Owner;
 		bool m_HasTitle, m_HasInitFileName, m_HasInitDirectory;
-		std::string m_Title, m_InitFileName, m_InitDirectory;
+		yycc_u8string m_Title, m_InitFileName, m_InitDirectory;
 		FileFilters m_FileTypes;
 		/**
 		 * @brief The default selected file type in dialog
@@ -210,11 +210,11 @@ namespace YYCC::DialogHelper {
 		size_t m_DefaultFileTypeIndex;
 	};
 
-	bool OpenFileDialog(const FileDialog& params, std::string& ret);
-	bool OpenMultipleFileDialog(const FileDialog& params, std::vector<std::string>& ret);
-	bool SaveFileDialog(const FileDialog& params, std::string& ret);
+	bool OpenFileDialog(const FileDialog& params, yycc_u8string& ret);
+	bool OpenMultipleFileDialog(const FileDialog& params, std::vector<yycc_u8string>& ret);
+	bool SaveFileDialog(const FileDialog& params, yycc_u8string& ret);
 
-	bool OpenFolderDialog(const FileDialog& params, std::string& ret);
+	bool OpenFolderDialog(const FileDialog& params, yycc_u8string& ret);
 
 }
 

src/EncodingHelper.cpp

@@ -4,88 +4,224 @@
 
 namespace YYCC::EncodingHelper {
 
+#pragma region UTF8 Native Convertion
+	
+	const yycc_char8_t* ToUTF8(const char* src) {
+		return reinterpret_cast<const yycc_char8_t*>(src);
+	}
+	yycc_char8_t* ToUTF8(char* src) {
+		return reinterpret_cast<yycc_char8_t*>(src);
+	}
+	yycc_u8string ToUTF8(const std::string_view& src) {
+		return yycc_u8string(reinterpret_cast<const yycc_char8_t*>(src.data()), src.size());
+	}
+	yycc_u8string_view ToUTF8View(const std::string_view& src) {
+		return yycc_u8string_view(reinterpret_cast<const yycc_char8_t*>(src.data()), src.size());
+	}
+	
+	const char* ToNative(const yycc_char8_t* src) {
+		return reinterpret_cast<const char*>(src);
+	}
+	char* ToNative(yycc_char8_t* src) {
+		return reinterpret_cast<char*>(src);
+	}
+	std::string ToNative(const yycc_u8string_view& src) {
+		return std::string(reinterpret_cast<const char*>(src.data()), src.size());
+	}
+	std::string_view ToNativeView(const yycc_u8string_view& src) {
+		return std::string_view(reinterpret_cast<const char*>(src.data()), src.size());
+	}
+
+#pragma endregion
+
+	/* Define some assistant macros for easy writing. */
+
+#define CONVFCT_TYPE2(fct_name, src_char_type, dst_char_type, ...) if (src == nullptr) return false; \
+std::basic_string_view<src_char_type> cache(src); \
+return fct_name(cache, dst, ##__VA_ARGS__);
+
+#define CONVFCT_TYPE3(fct_name, src_char_type, dst_char_type, ...) std::basic_string<dst_char_type> ret; \
+if (!fct_name(src, ret, ##__VA_ARGS__)) ret.clear(); \
+return ret;
+	
+#define CONVFCT_TYPE4(fct_name, src_char_type, dst_char_type, ...) std::basic_string<dst_char_type> ret; \
+if (!fct_name(src, ret, ##__VA_ARGS__)) ret.clear(); \
+return ret;
+
+
 #if YYCC_OS == YYCC_OS_WINDOWS
 
-	bool WcharToChar(const wchar_t* src, std::string& dest, UINT codepage) {
-		int count, write_result;
+#pragma region WcharToChar
+	
+	bool WcharToChar(const std::wstring_view& src, std::string& dst, UINT code_page) {
+		// if src is empty, direct output
+		if (src.empty()) {
+			dst.clear();
+			return true;
+		}
 
-		//converter to CHAR
-		count = WideCharToMultiByte(codepage, 0, reinterpret_cast<LPCWCH>(src), -1, NULL, 0, NULL, NULL);
-		if (count <= 0) return false;
+		// init WideCharToMultiByte used variables
+		// setup src pointer
+		LPCWCH lpWideCharStr =  reinterpret_cast<LPCWCH>(src.data());
+		// check whether source string is too large.
+		size_t cSrcSize = src.size();
+		if (cSrcSize > std::numeric_limits<int>::max()) return false;
+		int cchWideChar = static_cast<int>(src.size());
 
-		dest.resize(count - 1);
-		write_result = WideCharToMultiByte(codepage, 0, reinterpret_cast<LPCWCH>(src), -1, reinterpret_cast<LPSTR>(dest.data()), count, NULL, NULL);
+		// do convertion
+		// do a dry-run first to fetch desired size.
+		int desired_size = WideCharToMultiByte(code_page, 0, lpWideCharStr, cchWideChar, NULL, 0, NULL, NULL);
+		if (desired_size <= 0) return false;
+		// resize dest for receiving result
+		dst.resize(static_cast<size_t>(desired_size));
+		// do real convertion
+		int write_result = WideCharToMultiByte(code_page, 0, lpWideCharStr, cchWideChar, reinterpret_cast<LPSTR>(dst.data()), desired_size, NULL, NULL);
 		if (write_result <= 0) return false;
 
 		return true;
 	}
-	bool WcharToUTF8(const wchar_t* src, std::string& dest) {
-		return WcharToChar(src, dest, CP_UTF8);
+	bool WcharToChar(const wchar_t* src, std::string& dst, UINT code_page) {
+		CONVFCT_TYPE2(WcharToChar, wchar_t, char, code_page);
 	}
-	std::string WcharToChar(const wchar_t* src, UINT codepage) {
-		std::string ret;
-		if (!WcharToChar(src, ret, codepage)) ret.clear();
-		return ret;
+	std::string WcharToChar(const std::wstring_view& src, UINT code_page) {
+		CONVFCT_TYPE3(WcharToChar, wchar_t, char, code_page);
 	}
-	std::string WcharToUTF8(const wchar_t* src) {
-		return WcharToChar(src, CP_UTF8);
+	std::string WcharToChar(const wchar_t* src, UINT code_page) {
+		CONVFCT_TYPE4(WcharToChar, wchar_t, char, code_page);
 	}
 
-	bool CharToWchar(const char* src, std::wstring& dest, UINT codepage) {
-		int wcount, write_result;
+#pragma endregion
+	
+#pragma region CharToWchar
 
-		// convert to WCHAR
-		wcount = MultiByteToWideChar(codepage, 0, reinterpret_cast<LPCCH>(src), -1, NULL, 0);
-		if (wcount <= 0) return false;
+	bool CharToWchar(const std::string_view& src, std::wstring& dst, UINT code_page) {
+		// if src is empty, direct output
+		if (src.empty()) {
+			dst.clear();
+			return true;
+		}
 
-		dest.resize(wcount - 1);
-		write_result = MultiByteToWideChar(codepage, 0, reinterpret_cast<LPCCH>(src), -1, reinterpret_cast<LPWSTR>(dest.data()), wcount);
+		// init WideCharToMultiByte used variables
+		// setup src pointer
+		LPCCH lpMultiByteStr = reinterpret_cast<LPCCH>(src.data());
+		// check whether source string is too large.
+		size_t cSrcSize = src.size();
+		if (cSrcSize > std::numeric_limits<int>::max()) return false;
+		int cbMultiByte = static_cast<int>(src.size());
+		
+		// do convertion
+		// do a dry-run first to fetch desired size.
+		int desired_size = MultiByteToWideChar(code_page, 0, lpMultiByteStr, cbMultiByte, NULL, 0);
+		if (desired_size <= 0) return false;
+		// resize dest for receiving result
+		dst.resize(static_cast<size_t>(desired_size));
+		// do real convertion
+		int write_result = MultiByteToWideChar(code_page, 0, lpMultiByteStr, cbMultiByte, reinterpret_cast<LPWSTR>(dst.data()), desired_size);
 		if (write_result <= 0) return false;
 
 		return true;
 	}
-	bool UTF8ToWchar(const char* src, std::wstring& dest) {
-		return CharToWchar(src, dest, CP_UTF8);
+	bool CharToWchar(const char* src, std::wstring& dst, UINT code_page) {
+		CONVFCT_TYPE2(CharToWchar, char, wchar_t, code_page);
 	}
-	std::wstring CharToWchar(const char* src, UINT codepage) {
-		std::wstring ret;
-		if (!CharToWchar(src, ret, codepage)) ret.clear();
-		return ret;
+	std::wstring CharToWchar(const std::string_view& src, UINT code_page) {
+		CONVFCT_TYPE3(CharToWchar, char, wchar_t, code_page);
 	}
-	std::wstring UTF8ToWchar(const char* src) {
-		return CharToWchar(src, CP_UTF8);
+	std::wstring CharToWchar(const char* src, UINT code_page) {
+		CONVFCT_TYPE4(CharToWchar, char, wchar_t, code_page);
 	}
 
-	bool CharToChar(const char* src, std::string& dest, UINT src_codepage, UINT dest_codepage) {
+#pragma endregion
+
+#pragma region CharToChar
+	
+	bool CharToChar(const std::string_view& src, std::string& dst, UINT src_code_page, UINT dst_code_page) {
 		std::wstring intermediary;
-		if (!CharToWchar(src, intermediary, src_codepage)) return false;
-		if (!WcharToChar(intermediary.c_str(), dest, dest_codepage)) return false;
+		if (!CharToWchar(src, intermediary, src_code_page)) return false;
+		if (!WcharToChar(intermediary, dst, dst_code_page)) return false;
 		return true;
 	}
-	std::string CharToChar(const char* src, UINT src_codepage, UINT dest_codepage) {
-		std::string ret;
-		if (!CharToChar(src, ret, src_codepage, dest_codepage)) ret.clear();
-		return ret;
+	bool CharToChar(const char* src, std::string& dst, UINT src_code_page, UINT dst_code_page) {
+		CONVFCT_TYPE2(CharToChar, char, char, src_code_page, dst_code_page);
+	}
+	std::string CharToChar(const std::string_view& src, UINT src_code_page, UINT dst_code_page) {
+		CONVFCT_TYPE3(CharToChar, char, char, src_code_page, dst_code_page);
+	}
+	std::string CharToChar(const char* src, UINT src_code_page, UINT dst_code_page) {
+		CONVFCT_TYPE4(CharToChar, char, char, src_code_page, dst_code_page);
 	}
 
+#pragma endregion
+
+#pragma region WcharToUTF8
+	
+	bool WcharToUTF8(const std::wstring_view& src, yycc_u8string& dst) {
+		std::string adapted_dst;
+		bool ret = WcharToChar(src, adapted_dst, CP_UTF8);
+		if (ret) dst = ToUTF8(adapted_dst);
+		return ret;
+	}
+	bool WcharToUTF8(const wchar_t* src, yycc_u8string& dst) {
+		CONVFCT_TYPE2(WcharToUTF8, wchar_t, yycc_char8_t);
+	}
+	yycc_u8string WcharToUTF8(const std::wstring_view& src) {
+		CONVFCT_TYPE3(WcharToUTF8, wchar_t, yycc_char8_t);
+	}
+	yycc_u8string WcharToUTF8(const wchar_t* src) {
+		CONVFCT_TYPE4(WcharToUTF8, wchar_t, yycc_char8_t);
+	}
+
+#pragma endregion
+
+#pragma region UTF8ToWchar
+	
+	bool UTF8ToWchar(const yycc_u8string_view& src, std::wstring& dst) {
+		std::string_view adapted_src(ToNativeView(src));
+		return CharToWchar(adapted_src, dst, CP_UTF8);
+	}
+	bool UTF8ToWchar(const yycc_char8_t* src, std::wstring& dst) {
+		CONVFCT_TYPE2(UTF8ToWchar, yycc_char8_t, wchar_t);
+	}
+	std::wstring UTF8ToWchar(const yycc_u8string_view& src) {
+		CONVFCT_TYPE3(UTF8ToWchar, yycc_char8_t, wchar_t);
+	}
+	std::wstring UTF8ToWchar(const yycc_char8_t* src) {
+		CONVFCT_TYPE4(UTF8ToWchar, yycc_char8_t, wchar_t);
+	}
+
+#pragma endregion
+	
 #endif
 
+	
+#pragma region UTF8 UTF16 UTF32 Help Funcs
+
+	/*
+	According to the documentation introduced in CppReference.
+	The standard library is guaranteed to provide several specific specializations of \c std::codecvt.
+	The UTF8 char type in UTF8 related specializations of \c std::codecvt is different.
+	It is also independend from we defined \c yycc_char8_t.
+	So it is essential define a type which can correctly trigger specific specializations of \c std::codecv in there.
+	*/
 #if defined(__cpp_char8_t)
 	using CodecvtUTF8Char_t = char8_t;
 #else
 	using CodecvtUTF8Char_t = char;
 #endif
+
 	template<typename _TChar, std::enable_if_t<std::is_same_v<_TChar, char16_t> || std::is_same_v<_TChar, char32_t>, int> = 0>
 	using CodecvtFacet_t = std::codecvt<_TChar, CodecvtUTF8Char_t, std::mbstate_t>;
 
 	template<typename _TChar, std::enable_if_t<std::is_same_v<_TChar, char16_t> || std::is_same_v<_TChar, char32_t>, int> = 0>
-	static bool UTF8ToUTFOther(const char* _src, std::basic_string<_TChar>& dest) {
+	static bool UTF8ToUTFOther(const yycc_u8string_view& src, std::basic_string<_TChar>& dst) {
 		// Reference:
 		// https://zh.cppreference.com/w/cpp/locale/codecvt/in
 		
-		// init src string
-		if (_src == nullptr) return false;
-		std::string src(_src);
+		// if src is empty, return directly
+		if (src.empty()) {
+			dst.clear();
+			return true;
+		}
 
 		// init locale and get codecvt facet
 		// same reason in UTFOtherToUTF8 to keeping reference to locale
@@ -94,12 +230,12 @@ namespace YYCC::EncodingHelper {
 		
 		// convertion preparation
 		std::mbstate_t mb{};
-		dest.resize(src.size());
-		const CodecvtUTF8Char_t* intern_from = reinterpret_cast<const CodecvtUTF8Char_t*>(src.c_str()),
-			*intern_from_end = reinterpret_cast<const CodecvtUTF8Char_t*>(src.c_str() + src.size()),
+		dst.resize(src.size());
+		const CodecvtUTF8Char_t* intern_from = reinterpret_cast<const CodecvtUTF8Char_t*>(src.data()),
+			*intern_from_end = reinterpret_cast<const CodecvtUTF8Char_t*>(src.data() + src.size()),
 			*intern_from_next = nullptr;
-		_TChar* extern_to = dest.data(),
-			*extern_to_end = dest.data() + dest.size(),
+		_TChar* extern_to = dst.data(),
+			*extern_to_end = dst.data() + dst.size(),
 			*extern_to_next = nullptr;
 		// do convertion
 		auto result = this_codecvt.in(
@@ -112,35 +248,20 @@ namespace YYCC::EncodingHelper {
 		if (result != CodecvtFacet_t<_TChar>::ok)
 			return false;
 		// resize result and return
-		dest.resize(extern_to_next - dest.data());
+		dst.resize(extern_to_next - dst.data());
 		return true;
 	}
 
-	bool UTF8ToUTF16(const char* src, std::u16string& dest) {
-		return UTF8ToUTFOther<char16_t>(src, dest);
-	}
-	std::u16string UTF8ToUTF16(const char* src) {
-		std::u16string ret;
-		if (!UTF8ToUTF16(src, ret)) ret.clear();
-		return ret;
-	}
-	bool UTF8ToUTF32(const char* src, std::u32string& dest) {
-		return UTF8ToUTFOther<char32_t>(src, dest);
-	}
-	std::u32string UTF8ToUTF32(const char* src) {
-		std::u32string ret;
-		if (!UTF8ToUTF32(src, ret)) ret.clear();
-		return ret;
-	}
-
 	template<typename _TChar, std::enable_if_t<std::is_same_v<_TChar, char16_t> || std::is_same_v<_TChar, char32_t>, int> = 0>
-	static bool UTFOtherToUTF8(const _TChar* _src, std::string& dest) {
+	static bool UTFOtherToUTF8(const std::basic_string_view<_TChar>& src, yycc_u8string& dst) {
 		// Reference:
 		// https://zh.cppreference.com/w/cpp/locale/codecvt/out
 		
-		// initialize src string
-		if (_src == nullptr) return false;
-		std::basic_string<_TChar> src(_src);
+		// if src is empty, return directly
+		if (src.empty()) {
+			dst.clear();
+			return true;
+		}
 
 		// init locale and get codecvt facet
 		// the reference to locale must be preserved until convertion done.
@@ -150,12 +271,12 @@ namespace YYCC::EncodingHelper {
 
 		// do convertion preparation
 		std::mbstate_t mb{};
-		dest.resize(src.size() * this_codecvt.max_length());
-		const _TChar* intern_from = src.c_str(),
-			*intern_from_end = src.c_str() + src.size(),
+		dst.resize(src.size() * this_codecvt.max_length());
+		const _TChar* intern_from = src.data(),
+			*intern_from_end = src.data() + src.size(),
 			*intern_from_next = nullptr;
-		CodecvtUTF8Char_t* extern_to = reinterpret_cast<CodecvtUTF8Char_t*>(dest.data()),
-			*extern_to_end = reinterpret_cast<CodecvtUTF8Char_t*>(dest.data() + dest.size()),
+		CodecvtUTF8Char_t* extern_to = reinterpret_cast<CodecvtUTF8Char_t*>(dst.data()),
+			*extern_to_end = reinterpret_cast<CodecvtUTF8Char_t*>(dst.data() + dst.size()),
 			*extern_to_next = nullptr;
 		// do convertion
 		auto result = this_codecvt.out(
@@ -168,26 +289,83 @@ namespace YYCC::EncodingHelper {
 		if (result != CodecvtFacet_t<_TChar>::ok)
 			return false;
 		// resize result and retuen
-		dest.resize(extern_to_next - reinterpret_cast<CodecvtUTF8Char_t*>(dest.data()));
+		dst.resize(extern_to_next - reinterpret_cast<CodecvtUTF8Char_t*>(dst.data()));
 		return true;
 	}
 
-	bool UTF16ToUTF8(const char16_t* src, std::string& dest) {
-		return UTFOtherToUTF8<char16_t>(src, dest);
+#pragma endregion
+
+#pragma region UTF8ToUTF16
+	
+	bool UTF8ToUTF16(const yycc_u8string_view& src, std::u16string& dst) {
+		return UTF8ToUTFOther<char16_t>(src, dst);
 	}
-	std::string UTF16ToUTF8(const char16_t* src) {
-		std::string ret;
-		if (!UTF16ToUTF8(src, ret)) ret.clear();
-		return ret;
+	bool UTF8ToUTF16(const yycc_char8_t* src, std::u16string& dst) {
+		CONVFCT_TYPE2(UTF8ToUTF16, yycc_char8_t, char16_t);
 	}
-	bool UTF32ToUTF8(const char32_t* src, std::string& dest) {
-		return UTFOtherToUTF8<char32_t>(src, dest);
+	std::u16string UTF8ToUTF16(const yycc_u8string_view& src) {
+		CONVFCT_TYPE3(UTF8ToUTF16, yycc_char8_t, char16_t);
 	}
-	std::string UTF32ToUTF8(const char32_t* src) {
-		std::string ret;
-		if (!UTF32ToUTF8(src, ret)) ret.clear();
-		return ret;
+	std::u16string UTF8ToUTF16(const yycc_char8_t* src) {
+		CONVFCT_TYPE4(UTF8ToUTF16, yycc_char8_t, char16_t);
 	}
 
+#pragma endregion
+
+#pragma region UTF16ToUTF8
+	
+	bool UTF16ToUTF8(const std::u16string_view& src, yycc_u8string& dst) {
+		return UTFOtherToUTF8<char16_t>(src, dst);
+	}
+	bool UTF16ToUTF8(const char16_t* src, yycc_u8string& dst) {
+		CONVFCT_TYPE2(UTF16ToUTF8, char16_t, yycc_char8_t);
+	}
+	yycc_u8string UTF16ToUTF8(const std::u16string_view& src) {
+		CONVFCT_TYPE3(UTF16ToUTF8, char16_t, yycc_char8_t);
+	}
+	yycc_u8string UTF16ToUTF8(const char16_t* src) {
+		CONVFCT_TYPE4(UTF16ToUTF8, char16_t, yycc_char8_t);
+	}
+
+#pragma endregion
+	
+#pragma region UTF8ToUTF32
+	
+	bool UTF8ToUTF32(const yycc_u8string_view& src, std::u32string& dst) {
+		return UTF8ToUTFOther<char32_t>(src, dst);
+	}
+	bool UTF8ToUTF32(const yycc_char8_t* src, std::u32string& dst) {
+		CONVFCT_TYPE2(UTF8ToUTF32, yycc_char8_t, char32_t);
+	}
+	std::u32string UTF8ToUTF32(const yycc_u8string_view& src) {
+		CONVFCT_TYPE3(UTF8ToUTF32, yycc_char8_t, char32_t);
+	}
+	std::u32string UTF8ToUTF32(const yycc_char8_t* src) {
+		CONVFCT_TYPE4(UTF8ToUTF32, yycc_char8_t, char32_t);
+	}
+
+#pragma endregion
+
+#pragma region UTF32ToUTF8
+	
+	bool UTF32ToUTF8(const std::u32string_view& src, yycc_u8string& dst) {
+		return UTFOtherToUTF8<char32_t>(src, dst);
+	}
+	bool UTF32ToUTF8(const char32_t* src, yycc_u8string& dst) {
+		CONVFCT_TYPE2(UTF32ToUTF8, char32_t, yycc_char8_t);
+	}
+	yycc_u8string UTF32ToUTF8(const std::u32string_view& src) {
+		CONVFCT_TYPE3(UTF32ToUTF8, char32_t, yycc_char8_t);
+	}
+	yycc_u8string UTF32ToUTF8(const char32_t* src) {
+		CONVFCT_TYPE4(UTF32ToUTF8, char32_t, yycc_char8_t);
+	}
+
+#pragma endregion
+
+#undef CONVFCT_TYPE2
+#undef CONVFCT_TYPE3
+#undef CONVFCT_TYPE4
+
 }
 

src/EncodingHelper.hpp

@@ -21,20 +21,20 @@
  * \li \c UTF8: UTF8 string.
  * \li \c Wchar: wchar_t string.
  * \par
- * For example: \c WcharToUTF8 will perform the convertion from wchar_t to UTF8, 
+ * For example: \c WcharToUTF8 will perform the convertion from wchar_t to UTF8,
  * and \c CharToChar will perform the convertion between 2 code-page-based string and caller can specify individual code page for these 2 string.
  * \par
  * These functions are Windows specific and are unavailable on other platforms.
  * Becasue Windows use wchar_t string as its function arguments for globalization, and this library use UTF8 everywhere.
  * So it should have a bidirectional way to do convertion between wchar_t string and UTF8 string.
- * 
+ *
  * \par UTF32, UTF16 and UTF8 Convertion
  * This namespace also provide the convertion among UTF32, UTF16 and UTF8.
  * These convertion functions are suit for all platforms, not Windows oriented.
  * \par
  * Due to implementation, this library assume all non-Windows system use UTF8 as their C locale.
  * Otherwise these functions will produce wrong result.
- * 
+ *
  * \par Function Parameters
  * We provide these encoding convertion functions with following 2 types:
  * \li Function returns \c bool and its parameter order source string pointer and a corresponding \c std::basic_string container for receiving result.
@@ -46,35 +46,72 @@
  * First declaration will return false to indicate there is an error when doing convertion. Please note that the content of string container passing in may still be changed!
  * Last declaration will return empty string to indicate error. Please note if you pass empty string in, they still will output empty string but it doesn't mean an error.
  * So last declaration is used in the scenario that we don't care whether the convertion success did. For example, output something to console.
- * 
+ *
 */
 namespace YYCC::EncodingHelper {
 
+#define _YYCC_U8(strl) u8 ## strl
+#define YYCC_U8(strl) (reinterpret_cast<const ::YYCC::yycc_char8_t*>(_YYCC_U8(strl)))
+
+	const yycc_char8_t* ToUTF8(const char* src);
+	yycc_char8_t* ToUTF8(char* src);
+	yycc_u8string ToUTF8(const std::string_view& src);
+	yycc_u8string_view ToUTF8View(const std::string_view& src);
+
+	const char* ToNative(const yycc_char8_t* src);
+	char* ToNative(yycc_char8_t* src);
+	std::string ToNative(const yycc_u8string_view& src);
+	std::string_view ToNativeView(const yycc_u8string_view& src);
+
 #if YYCC_OS == YYCC_OS_WINDOWS
 
-	bool WcharToChar(const wchar_t* src, std::string& dest, UINT codepage);
-	bool WcharToUTF8(const wchar_t* src, std::string& dest);
-	std::string WcharToChar(const wchar_t* src, UINT codepage);
-	std::string WcharToUTF8(const wchar_t* src);
+	bool WcharToChar(const std::wstring_view& src, std::string& dst, UINT code_page);
+	bool WcharToChar(const wchar_t* src, std::string& dst, UINT code_page);
+	std::string WcharToChar(const std::wstring_view& src, UINT code_page);
+	std::string WcharToChar(const wchar_t* src, UINT code_page);
 
-	bool CharToWchar(const char* src, std::wstring& dest, UINT codepage);
-	bool UTF8ToWchar(const char* src, std::wstring& dest);
-	std::wstring CharToWchar(const char* src, UINT codepage);
-	std::wstring UTF8ToWchar(const char* src);
+	bool CharToWchar(const std::string_view& src, std::wstring& dst, UINT code_page);
+	bool CharToWchar(const char* src, std::wstring& dst, UINT code_page);
+	std::wstring CharToWchar(const std::string_view& src, UINT code_page);
+	std::wstring CharToWchar(const char* src, UINT code_page);
 
-	bool CharToChar(const char* src, std::string& dest, UINT src_codepage, UINT dest_codepage);
-	std::string CharToChar(const char* src, UINT src_codepage, UINT dest_codepage);
+	bool CharToChar(const std::string_view& src, std::string& dst, UINT src_code_page, UINT dst_code_page);
+	bool CharToChar(const char* src, std::string& dst, UINT src_code_page, UINT dst_code_page);
+	std::string CharToChar(const std::string_view& src, UINT src_code_page, UINT dst_code_page);
+	std::string CharToChar(const char* src, UINT src_code_page, UINT dst_code_page);
+
+
+	bool WcharToUTF8(const std::wstring_view& src, yycc_u8string& dst);
+	bool WcharToUTF8(const wchar_t* src, yycc_u8string& dst);
+	yycc_u8string WcharToUTF8(const std::wstring_view& src);
+	yycc_u8string WcharToUTF8(const wchar_t* src);
+
+	bool UTF8ToWchar(const yycc_u8string_view& src, std::wstring& dst);
+	bool UTF8ToWchar(const yycc_char8_t* src, std::wstring& dst);
+	std::wstring UTF8ToWchar(const yycc_u8string_view& src);
+	std::wstring UTF8ToWchar(const yycc_char8_t* src);
 
 #endif
 
-	bool UTF8ToUTF16(const char* src, std::u16string& dest);
-	std::u16string UTF8ToUTF16(const char* src);
-	bool UTF8ToUTF32(const char* src, std::u32string& dest);
-	std::u32string UTF8ToUTF32(const char* src);
+	bool UTF8ToUTF16(const yycc_u8string_view& src, std::u16string& dst);
+	bool UTF8ToUTF16(const yycc_char8_t* src, std::u16string& dst);
+	std::u16string UTF8ToUTF16(const yycc_u8string_view& src);
+	std::u16string UTF8ToUTF16(const yycc_char8_t* src);
 
-	bool UTF16ToUTF8(const char16_t* src, std::string& dest);
-	std::string  UTF16ToUTF8(const char16_t* src);
-	bool UTF32ToUTF8(const char32_t* src, std::string& dest);
-	std::string  UTF32ToUTF8(const char32_t* src);
+	bool UTF16ToUTF8(const std::u16string_view& src, yycc_u8string& dst);
+	bool UTF16ToUTF8(const char16_t* src, yycc_u8string& dst);
+	yycc_u8string UTF16ToUTF8(const std::u16string_view& src);
+	yycc_u8string UTF16ToUTF8(const char16_t* src);
+
+
+	bool UTF8ToUTF32(const yycc_u8string_view& src, std::u32string& dst);
+	bool UTF8ToUTF32(const yycc_char8_t* src, std::u32string& dst);
+	std::u32string UTF8ToUTF32(const yycc_u8string_view& src);
+	std::u32string UTF8ToUTF32(const yycc_char8_t* src);
+
+	bool UTF32ToUTF8(const std::u32string_view& src, yycc_u8string& dst);
+	bool UTF32ToUTF8(const char32_t* src, yycc_u8string& dst);
+	yycc_u8string UTF32ToUTF8(const std::u32string_view& src);
+	yycc_u8string UTF32ToUTF8(const char32_t* src);
 
 }

src/ExceptionHelper.cpp

@@ -59,50 +59,50 @@ namespace YYCC::ExceptionHelper {
 	 * @param[in] code Exception code
 	 * @return The const string pointer to corresponding exception explanation string.
 	*/
-	static const char* UExceptionGetCodeName(DWORD code) {
+	static const yycc_char8_t* UExceptionGetCodeName(DWORD code) {
 		switch (code) {
 			case EXCEPTION_ACCESS_VIOLATION:
-				return "access violation";
+				return YYCC_U8("access violation");
 			case EXCEPTION_ARRAY_BOUNDS_EXCEEDED:
-				return "array index out of bound";
+				return YYCC_U8("array index out of bound");
 			case EXCEPTION_BREAKPOINT:
-				return "breakpoint reached";
+				return YYCC_U8("breakpoint reached");
 			case EXCEPTION_DATATYPE_MISALIGNMENT:
-				return "misaligned data access";
+				return YYCC_U8("misaligned data access");
 			case EXCEPTION_FLT_DENORMAL_OPERAND:
-				return "operand had denormal value";
+				return YYCC_U8("operand had denormal value");
 			case EXCEPTION_FLT_DIVIDE_BY_ZERO:
-				return "floating-point division by zero";
+				return YYCC_U8("floating-point division by zero");
 			case EXCEPTION_FLT_INEXACT_RESULT:
-				return "no decimal fraction representation for value";
+				return YYCC_U8("no decimal fraction representation for value");
 			case EXCEPTION_FLT_INVALID_OPERATION:
-				return "invalid floating-point operation";
+				return YYCC_U8("invalid floating-point operation");
 			case EXCEPTION_FLT_OVERFLOW:
-				return "floating-point overflow";
+				return YYCC_U8("floating-point overflow");
 			case EXCEPTION_FLT_STACK_CHECK:
-				return "floating-point stack corruption";
+				return YYCC_U8("floating-point stack corruption");
 			case EXCEPTION_FLT_UNDERFLOW:
-				return "floating-point underflow";
+				return YYCC_U8("floating-point underflow");
 			case EXCEPTION_ILLEGAL_INSTRUCTION:
-				return "illegal instruction";
+				return YYCC_U8("illegal instruction");
 			case EXCEPTION_IN_PAGE_ERROR:
-				return "inaccessible page";
+				return YYCC_U8("inaccessible page");
 			case EXCEPTION_INT_DIVIDE_BY_ZERO:
-				return "integer division by zero";
+				return YYCC_U8("integer division by zero");
 			case EXCEPTION_INT_OVERFLOW:
-				return "integer overflow";
+				return YYCC_U8("integer overflow");
 			case EXCEPTION_INVALID_DISPOSITION:
-				return "documentation says this should never happen";
+				return YYCC_U8("documentation says this should never happen");
 			case EXCEPTION_NONCONTINUABLE_EXCEPTION:
-				return "can't continue after a noncontinuable exception";
+				return YYCC_U8("can't continue after a noncontinuable exception");
 			case EXCEPTION_PRIV_INSTRUCTION:
-				return "attempted to execute a privileged instruction";
+				return YYCC_U8("attempted to execute a privileged instruction");
 			case EXCEPTION_SINGLE_STEP:
-				return "one instruction has been executed";
+				return YYCC_U8("one instruction has been executed");
 			case EXCEPTION_STACK_OVERFLOW:
-				return "stack overflow";
+				return YYCC_U8("stack overflow");
 			default:
-				return "unknown exception";
+				return YYCC_U8("unknown exception");
 		}
 	}
 
@@ -117,12 +117,12 @@ namespace YYCC::ExceptionHelper {
 	 * @param[in] fmt The format string.
 	 * @param[in] ... The argument to be formatted.
 	*/
-	static void UExceptionErrLogFormatLine(std::FILE* fs, const char* fmt, ...) {
+	static void UExceptionErrLogFormatLine(std::FILE* fs, const yycc_char8_t* fmt, ...) {
 		// write to file
 		if (fs != nullptr) {
 			va_list arg1;
 			va_start(arg1, fmt);
-			std::vfprintf(fs, fmt, arg1);
+			std::vfprintf(fs, EncodingHelper::ToNative(fmt), arg1);
 			std::fputs("\n", fs);
 			va_end(arg1);
 		}
@@ -142,10 +142,10 @@ namespace YYCC::ExceptionHelper {
 	 * If it is nullptr, function will skip writing for file stream.
 	 * @param[in] strl The string to be written.
 	*/
-	static void UExceptionErrLogWriteLine(std::FILE* fs, const char* strl) {
+	static void UExceptionErrLogWriteLine(std::FILE* fs, const yycc_char8_t* strl) {
 		// write to file
 		if (fs != nullptr) {
-			std::fputs(strl, fs);
+			std::fputs(EncodingHelper::ToNative(strl), fs);
 			std::fputs("\n", fs);
 		}
 		// write to stderr
@@ -163,7 +163,7 @@ namespace YYCC::ExceptionHelper {
 		// init symbol
 		if (!SymInitialize(process, 0, TRUE)) {
 			// fail to init. return
-			UExceptionErrLogWriteLine(fs, "Fail to initialize symbol handle for process!");
+			UExceptionErrLogWriteLine(fs, YYCC_U8("Fail to initialize symbol handle for process!"));
 			return;
 		}
 
@@ -215,13 +215,13 @@ namespace YYCC::ExceptionHelper {
 			// depth breaker
 			--maxdepth;
 			if (maxdepth < 0) {
-				UExceptionErrLogWriteLine(fs, "...");		// indicate there are some frames not listed
+				UExceptionErrLogWriteLine(fs, YYCC_U8("..."));		// indicate there are some frames not listed
 				break;
 			}
 
 			// get module name
-			const char* module_name = "<unknown module>";
-			std::string module_name_raw;
+			const yycc_char8_t* module_name = YYCC_U8("<unknown module>");
+			yycc_u8string module_name_raw;
 			DWORD64 module_base;
 			if (module_base = SymGetModuleBase64(process, frame.AddrPC.Offset)) {
 				if (WinFctHelper::GetModuleFileName((HINSTANCE)module_base, module_name_raw)) {
@@ -230,18 +230,18 @@ namespace YYCC::ExceptionHelper {
 			}
 
 			// get source file and line
-			const char* source_file = "<unknown source>";
+			const yycc_char8_t* source_file = YYCC_U8("<unknown source>");
 			DWORD64 source_file_line = 0;
 			DWORD dwDisplacement;
 			IMAGEHLP_LINE64 winline;
 			winline.SizeOfStruct = sizeof(IMAGEHLP_LINE64);
 			if (SymGetLineFromAddr64(process, frame.AddrPC.Offset, &dwDisplacement, &winline)) {
-				source_file = winline.FileName;
+				source_file = EncodingHelper::ToUTF8(winline.FileName); // TODO: check whether there is UNICODE file name.
 				source_file_line = winline.LineNumber;
 			}
 
 			// write to file
-			UExceptionErrLogFormatLine(fs, "0x%" PRI_XPTR_LEFT_PADDING PRIXPTR "[%s+0x%" PRI_XPTR_LEFT_PADDING PRIXPTR "]\t%s#L%" PRIu64,
+			UExceptionErrLogFormatLine(fs, YYCC_U8("0x%" PRI_XPTR_LEFT_PADDING PRIXPTR "[%s+0x%" PRI_XPTR_LEFT_PADDING PRIXPTR "]\t%s#L%" PRIu64),
 				frame.AddrPC.Offset, // memory adress
 				module_name, frame.AddrPC.Offset - module_base, // module name + relative address
 				source_file, source_file_line // source file + source line
@@ -255,16 +255,16 @@ namespace YYCC::ExceptionHelper {
 		SymCleanup(process);
 	}
 
-	static void UExceptionErrorLog(const std::string& u8_filename, LPEXCEPTION_POINTERS info) {
+	static void UExceptionErrorLog(const yycc_u8string& u8_filename, LPEXCEPTION_POINTERS info) {
 		// open file stream if we have file name
 		std::FILE* fs = nullptr;
 		if (!u8_filename.empty()) {
-			fs = IOHelper::UTF8FOpen(u8_filename.c_str(), "wb");
+			fs = IOHelper::UTF8FOpen(u8_filename.c_str(), YYCC_U8("wb"));
 		}
 
 		// record exception type first
 		PEXCEPTION_RECORD rec = info->ExceptionRecord;
-		UExceptionErrLogFormatLine(fs, "Unhandled exception occured at 0x%" PRI_XPTR_LEFT_PADDING PRIXPTR ": %s (%" PRIu32 ").",
+		UExceptionErrLogFormatLine(fs, YYCC_U8("Unhandled exception occured at 0x%" PRI_XPTR_LEFT_PADDING PRIXPTR ": %s (%" PRIu32 ")."),
 			rec->ExceptionAddress,
 			UExceptionGetCodeName(rec->ExceptionCode),
 			rec->ExceptionCode
@@ -273,10 +273,10 @@ namespace YYCC::ExceptionHelper {
 		// special proc for 2 exceptions
 		if (rec->ExceptionCode == EXCEPTION_ACCESS_VIOLATION || rec->ExceptionCode == EXCEPTION_IN_PAGE_ERROR) {
 			if (rec->NumberParameters >= 2) {
-				const char* op =
-					rec->ExceptionInformation[0] == 0 ? "read" :
-					rec->ExceptionInformation[0] == 1 ? "written" : "executed";
-				UExceptionErrLogFormatLine(fs, "The data at memory address 0x%" PRI_XPTR_LEFT_PADDING PRIxPTR " could not be %s.",
+				const yycc_char8_t* op =
+					rec->ExceptionInformation[0] == 0 ? YYCC_U8("read") :
+					rec->ExceptionInformation[0] == 1 ? YYCC_U8("written") : YYCC_U8("executed");
+				UExceptionErrLogFormatLine(fs, YYCC_U8("The data at memory address 0x%" PRI_XPTR_LEFT_PADDING PRIxPTR " could not be %s."),
 					rec->ExceptionInformation[1], op);
 			}
 		}
@@ -290,12 +290,12 @@ namespace YYCC::ExceptionHelper {
 		}
 	}
 
-	static void UExceptionCoreDump(const std::string& u8_filename, LPEXCEPTION_POINTERS info) {
+	static void UExceptionCoreDump(const yycc_u8string& u8_filename, LPEXCEPTION_POINTERS info) {
 		// convert file encoding
 		std::wstring filename;
 		if (u8_filename.empty())
 			return; // if no given file name, return
-		if (!YYCC::EncodingHelper::UTF8ToWchar(u8_filename.c_str(), filename))
+		if (!YYCC::EncodingHelper::UTF8ToWchar(u8_filename, filename))
 			return; // if convertion failed, return
 
 		// open file and write
@@ -315,18 +315,18 @@ namespace YYCC::ExceptionHelper {
 		}
 	}
 
-	static bool UExceptionFetchRecordPath(std::string& log_path, std::string& coredump_path) {
+	static bool UExceptionFetchRecordPath(yycc_u8string& log_path, yycc_u8string& coredump_path) {
 		// build two file names like: "module.dll.1234.log" and "module.dll.1234.dmp".
 		// "module.dll" is the name of current module. "1234" is current process id.
 		// get self module name
-		std::string u8_self_module_name;
+		yycc_u8string u8_self_module_name;
 		{
 			// get module handle
 			HMODULE hSelfModule = YYCC::WinFctHelper::GetCurrentModule();
 			if (hSelfModule == nullptr)
 				return false;
 			// get full path of self module
-			std::string u8_self_module_path;
+			yycc_u8string u8_self_module_path;
 			if (!YYCC::WinFctHelper::GetModuleFileName(hSelfModule, u8_self_module_path))
 				return false;
 			// extract file name from full path by std::filesystem::path
@@ -336,22 +336,22 @@ namespace YYCC::ExceptionHelper {
 		// then get process id
 		DWORD process_id = GetCurrentProcessId();
 		// conbine them as a file name prefix
-		std::string u8_filename_prefix;
-		if (!YYCC::StringHelper::Printf(u8_filename_prefix, "%s.%" PRIu32, u8_self_module_name.c_str(), process_id))
+		yycc_u8string u8_filename_prefix;
+		if (!YYCC::StringHelper::Printf(u8_filename_prefix, YYCC_U8("%s.%" PRIu32), u8_self_module_name.c_str(), process_id))
 			return false;
 		// then get file name for log and minidump
-		std::string u8_log_filename = u8_filename_prefix + ".log";
-		std::string u8_coredump_filename = u8_filename_prefix + ".dmp";
+		yycc_u8string u8_log_filename = u8_filename_prefix + YYCC_U8(".log");
+		yycc_u8string u8_coredump_filename = u8_filename_prefix + YYCC_U8(".dmp");
 
 		// fetch crash report path
 		// get local appdata folder
-		std::string u8_localappdata_path;
+		yycc_u8string u8_localappdata_path;
 		if (!WinFctHelper::GetLocalAppData(u8_localappdata_path))
 			return false;
 		// convert to std::filesystem::path
 		std::filesystem::path crash_report_path(FsPathPatch::FromUTF8Path(u8_localappdata_path.c_str()));
 		// slash into crash report folder
-		crash_report_path /= FsPathPatch::FromUTF8Path("CrashDumps");
+		crash_report_path /= FsPathPatch::FromUTF8Path(YYCC_U8("CrashDumps"));
 		// use create function to make sure it is existing
 		std::filesystem::create_directories(crash_report_path);
 
@@ -375,18 +375,18 @@ namespace YYCC::ExceptionHelper {
 		// core implementation
 		{
 			// fetch error report path first
-			std::string log_path, coredump_path;
+			yycc_u8string log_path, coredump_path;
 			if (!UExceptionFetchRecordPath(log_path, coredump_path)) {
 				// fail to fetch path, clear them.
 				// we still can handle crash without them
 				log_path.clear();
 				coredump_path.clear();
 				// and tell user we can not output file
-				ConsoleHelper::ErrWriteLine("Crash occurs, but we can not create crash log and coredump!");
+				ConsoleHelper::ErrWriteLine(YYCC_U8("Crash occurs, but we can not create crash log and coredump!"));
 			} else {
 				// okey. output file path to tell user the path where you can find.
-				ConsoleHelper::ErrFormatLine("Crash Log: %s", log_path.c_str());
-				ConsoleHelper::ErrFormatLine("Crash Coredump: %s", coredump_path.c_str());
+				ConsoleHelper::ErrFormatLine(YYCC_U8("Crash Log: %s"), log_path.c_str());
+				ConsoleHelper::ErrFormatLine(YYCC_U8("Crash Coredump: %s"), coredump_path.c_str());
 			}
 
 			// write crash log

src/FsPathPatch.cpp

@@ -6,7 +6,7 @@
 
 namespace YYCC::FsPathPatch {
 
-	std::filesystem::path FromUTF8Path(const char* u8_path) {
+	std::filesystem::path FromUTF8Path(const yycc_char8_t* u8_path) {
 #if YYCC_OS == YYCC_OS_WINDOWS
 
 		// convert path to wchar
@@ -14,19 +14,19 @@ namespace YYCC::FsPathPatch {
 		if (!YYCC::EncodingHelper::UTF8ToWchar(u8_path, wpath))
 			throw std::invalid_argument("Fail to convert given UTF8 string.");
 
-		// call microsoft specified fopen which support wchar as argument.
+		// return path with wchar_t ctor
 		return std::filesystem::path(wpath);
-
+		
 #else
-		return std::filesystem::path(u8_path);
+		return std::filesystem::path(EncodingHelper::ToNative(u8_path));
 #endif
 	}
 
-	std::string ToUTF8Path(const std::filesystem::path& path) {
+	yycc_u8string ToUTF8Path(const std::filesystem::path& path) {
 #if YYCC_OS == YYCC_OS_WINDOWS
 
 		// get and convert to utf8
-		std::string u8_path;
+		yycc_u8string u8_path;
 		if (!YYCC::EncodingHelper::WcharToUTF8(path.c_str(), u8_path))
 			throw std::invalid_argument("Fail to convert to UTF8 string.");
 
@@ -34,7 +34,7 @@ namespace YYCC::FsPathPatch {
 		return u8_path;
 
 #else
-		return path.string();
+		return EncodingHelper::ToUTF8(path.string());
 #endif
 	}
 

src/FsPathPatch.hpp

@@ -28,7 +28,7 @@ namespace YYCC::FsPathPatch {
 	 * @return std::filesystem::path instance.
 	 * @exception std::invalid_argument Fail to parse given UTF8 string (maybe invalid?).
 	*/
-	std::filesystem::path FromUTF8Path(const char* u8_path);
+	std::filesystem::path FromUTF8Path(const yycc_char8_t* u8_path);
 
 	/**
 	 * @brief Returns the UTF8 representation of the pathname
@@ -36,6 +36,6 @@ namespace YYCC::FsPathPatch {
 	 * @return UTF8 encoded string representing given path.
 	 * @exception std::invalid_argument Fail to parse to UTF8 string.
 	*/
-	std::string ToUTF8Path(const std::filesystem::path& path);
+	yycc_u8string ToUTF8Path(const std::filesystem::path& path);
 
 }

src/IOHelper.cpp

@@ -14,7 +14,7 @@
 
 namespace YYCC::IOHelper {
 
-	FILE* UTF8FOpen(const char* u8_filepath, const char* u8_mode) {
+	FILE* UTF8FOpen(const yycc_char8_t* u8_filepath, const yycc_char8_t* u8_mode) {
 #if YYCC_OS == YYCC_OS_WINDOWS
 
 		// convert mode and file path to wchar

src/IOHelper.hpp

@@ -32,6 +32,6 @@ namespace YYCC::IOHelper {
 	 * On other platforms, this function will delegate request directly to std::fopen.
 	 * @return FILE* of the file to be opened, or nullptr if failed.
 	*/
-	FILE* UTF8FOpen(const char* u8_filepath, const char* u8_mode);
+	FILE* UTF8FOpen(const yycc_char8_t* u8_filepath, const yycc_char8_t* u8_mode);
 	
 }

src/ParserHelper.hpp

@@ -14,11 +14,15 @@ namespace YYCC::ParserHelper {
 	// Reference: https://zh.cppreference.com/w/cpp/utility/from_chars
 
 	template<typename _Ty, std::enable_if_t<std::is_floating_point_v<_Ty>, int> = 0>
-	bool TryParse(const std::string& strl, _Ty& num) {
-		auto [ptr, ec] = std::from_chars(strl.c_str(), strl.c_str() + strl.size(), num, std::chars_format::general);
+	bool TryParse(const yycc_u8string_view& strl, _Ty& num) {
+		auto [ptr, ec] = std::from_chars(
+			EncodingHelper::ToNative(strl.data()), 
+			EncodingHelper::ToNative(strl.data() + strl.size()), 
+			num, std::chars_format::general
+		);
 		if (ec == std::errc()) {
 			// check whether the full string is matched
-			return ptr == strl.c_str() + strl.size();
+			return ptr == EncodingHelper::ToNative(strl.data() + strl.size());
 		} else if (ec == std::errc::invalid_argument) {
 			// given string is invalid
 			return false;
@@ -31,11 +35,15 @@ namespace YYCC::ParserHelper {
 		}
 	}
 	template<typename _Ty, std::enable_if_t<std::is_integral_v<_Ty> && !std::is_same_v<_Ty, bool>, int> = 0>
-	bool TryParse(const std::string& strl, _Ty& num, int base = 10) {
-		auto [ptr, ec] = std::from_chars(strl.c_str(), strl.c_str() + strl.size(), num, base);
+	bool TryParse(const yycc_u8string_view& strl, _Ty& num, int base = 10) {
+		auto [ptr, ec] = std::from_chars(
+			EncodingHelper::ToNative(strl.data()), 
+			EncodingHelper::ToNative(strl.data() + strl.size()), 
+			num, base
+		);
 		if (ec == std::errc()) {
 			// check whether the full string is matched
-			return ptr == strl.c_str() + strl.size();
+			return ptr == EncodingHelper::ToNative(strl.data() + strl.size());
 		} else if (ec == std::errc::invalid_argument) {
 			// given string is invalid
 			return false;
@@ -48,15 +56,15 @@ namespace YYCC::ParserHelper {
 		}
 	}
 	template<typename _Ty, std::enable_if_t<std::is_same_v<_Ty, bool>, int> = 0>
-	bool TryParse(const std::string& strl, _Ty& num) {
-		if (strl == "true") num = true;
-		else if (strl == "false") num = false;
+	bool TryParse(const yycc_u8string_view& strl, _Ty& num) {
+		if (strl == YYCC_U8("true")) num = true;
+		else if (strl == YYCC_U8("false")) num = false;
 		else return false;
 		return true;
 	}
 
 	template<typename _Ty, std::enable_if_t<std::is_arithmetic_v<_Ty>, int> = 0>
-	_Ty Parse(const std::string& strl) {
+	_Ty Parse(const yycc_u8string_view& strl) {
 		_Ty ret;
 		TryParse(strl, ret);
 		return ret;
@@ -65,11 +73,15 @@ namespace YYCC::ParserHelper {
 	// Reference: https://en.cppreference.com/w/cpp/utility/to_chars
 
 	template<typename _Ty, std::enable_if_t<std::is_arithmetic_v<_Ty> && !std::is_same_v<_Ty, bool>, int> = 0>
-	std::string ToString(_Ty num) {
-		std::array<char, 64> buffer;
-		auto [ptr, ec] = std::to_chars(buffer.data(), buffer.data() + buffer.size(), num);
+	yycc_u8string ToString(_Ty num) {
+		std::array<yycc_char8_t, 64> buffer;
+		auto [ptr, ec] = std::to_chars(
+			EncodingHelper::ToNative(buffer.data()), 
+			EncodingHelper::ToNative(buffer.data() + buffer.size()), 
+			num
+		);
 		if (ec == std::errc()) {
-			return std::string(buffer.data(), ptr - buffer.data());
+			return yycc_u8string(buffer.data(), EncodingHelper::ToUTF8(ptr) - buffer.data());
 		} else if (ec == std::errc::value_too_large) {
 			// too short buffer
 			// this should not happend
@@ -80,9 +92,9 @@ namespace YYCC::ParserHelper {
 		}
 	}
 	template<typename _Ty, std::enable_if_t<std::is_same_v<_Ty, bool>, int> = 0>
-	std::string ToString(_Ty num) {
-		if (num) return std::string("true");
-		else return std::string("false");
+	yycc_u8string ToString(_Ty num) {
+		if (num) return yycc_u8string(YYCC_U8("true"));
+		else return yycc_u8string(YYCC_U8("false"));
 	}
 
 }

src/StringHelper.cpp

@@ -1,9 +1,12 @@
 #include "StringHelper.hpp"
+#include "EncodingHelper.hpp"
 #include <algorithm>
 
 namespace YYCC::StringHelper {
 
-	bool Printf(std::string& strl, const char* format, ...) {
+#pragma region Printf VPrintf
+
+	bool Printf(yycc_u8string& strl, const yycc_char8_t* format, ...) {
 		va_list argptr;
 		va_start(argptr, format);
 		bool ret = VPrintf(strl, format, argptr);
@@ -11,7 +14,7 @@ namespace YYCC::StringHelper {
 		return ret;
 	}
 
-	bool VPrintf(std::string& strl, const char* format, va_list argptr) {
+	bool VPrintf(yycc_u8string& strl, const yycc_char8_t* format, va_list argptr) {
 		va_list args1;
 		va_copy(args1, argptr);
 		va_list args2;
@@ -19,7 +22,12 @@ namespace YYCC::StringHelper {
 
 		// the return value is desired char count without NULL terminal.
 		// minus number means error
-		int count = std::vsnprintf(nullptr, 0, format, args1);
+		int count = std::vsnprintf(
+			nullptr, 
+			0, 
+			EncodingHelper::ToNative(format), 
+			args1
+		);
 		if (count < 0) {
 			// invalid length returned by vsnprintf.
 			return false;
@@ -31,7 +39,12 @@ namespace YYCC::StringHelper {
 		// because std::vsnprintf only can write "buf_size - 1" chars with a trailing NULL.
 		// however std::vsnprintf already have a trailing NULL, so we plus 1 for it.
 		strl.resize(count);
-		int write_result = std::vsnprintf(strl.data(), strl.size() + 1, format, args2);
+		int write_result = std::vsnprintf(
+			EncodingHelper::ToNative(strl.data()),
+			strl.size() + 1, 
+			EncodingHelper::ToNative(format), 
+			args2
+		);
 		va_end(args2);
 
 		if (write_result < 0 || write_result > count) {
@@ -42,9 +55,8 @@ namespace YYCC::StringHelper {
 		return true;
 	}
 
-
-	std::string Printf(const char* format, ...) {
-		std::string ret;
+	yycc_u8string Printf(const yycc_char8_t* format, ...) {
+		yycc_u8string ret;
 
 		va_list argptr;
 		va_start(argptr, format);
@@ -54,8 +66,8 @@ namespace YYCC::StringHelper {
 		return ret;
 	}
 
-	std::string VPrintf(const char* format, va_list argptr) {
-		std::string ret;
+	yycc_u8string VPrintf(const yycc_char8_t* format, va_list argptr) {
+		yycc_u8string ret;
 
 		va_list argcpy;
 		va_copy(argcpy, argptr);
@@ -65,28 +77,32 @@ namespace YYCC::StringHelper {
 		return ret;
 	}
 
-	void Replace(std::string& strl, const char* _from_strl, const char* _to_strl)  {
+#pragma endregion
+
+#pragma region Replace
+
+	void Replace(yycc_u8string& strl, const yycc_char8_t* _from_strl, const yycc_char8_t* _to_strl)  {
 		// Reference: https://stackoverflow.com/questions/3418231/replace-part-of-a-string-with-another-string
 		
 		// check requirements
 		// from string and to string should not be nullptr.
 		if (_from_strl == nullptr || _to_strl == nullptr) return;
 		// from string should not be empty
-		std::string from_strl(_from_strl);
-		std::string to_strl(_to_strl);
+		yycc_u8string from_strl(_from_strl);
+		yycc_u8string to_strl(_to_strl);
 		if (from_strl.empty()) return;
 
 		// start replace one by one
 		size_t start_pos = 0;
-		while ((start_pos = strl.find(from_strl, start_pos)) != std::string::npos) {
+		while ((start_pos = strl.find(from_strl, start_pos)) != yycc_u8string::npos) {
 			strl.replace(start_pos, from_strl.size(), to_strl);
 			start_pos += to_strl.size(); // In case 'to' contains 'from', like replacing 'x' with 'yx'
 		}
 	}
 
-	std::string Replace(const char* _strl, const char* _from_strl, const char* _to_strl) {
+	yycc_u8string Replace(const yycc_char8_t* _strl, const yycc_char8_t* _from_strl, const yycc_char8_t* _to_strl) {
 		// prepare result
-		std::string strl;
+		yycc_u8string strl;
 		// if given string is not nullptr, assign it and process it.
 		if (_strl != nullptr) {
 			strl = _strl;
@@ -96,13 +112,17 @@ namespace YYCC::StringHelper {
 		return strl;
 	}
 
-	std::string Join(JoinDataProvider fct_data, const char* decilmer) {
-		std::string ret;
+#pragma endregion
+
+#pragma region Join
+
+	yycc_u8string Join(JoinDataProvider fct_data, const yycc_char8_t* decilmer) {
+		yycc_u8string ret;
 		bool is_first = true;
-		const char* element;
+		yycc_u8string_view element;
 
 		// fetch element
-		while ((element = fct_data()) != nullptr) {
+		while (fct_data(element)) {
 			// insert decilmer
 			if (is_first) is_first = false;
 			else {
@@ -111,42 +131,46 @@ namespace YYCC::StringHelper {
 					ret.append(decilmer);
 			}
 
-			// insert element
-			ret.append(element);
+			// insert element if it is not empty
+			if (!element.empty())
+				ret.append(element);
 		}
 
 		return ret;
 	}
 
-	std::string Join(const std::vector<std::string>& data, const char* decilmer, bool reversed) {
+	yycc_u8string Join(const std::vector<yycc_u8string>& data, const yycc_char8_t* decilmer, bool reversed) {
 		if (reversed) {
 			auto iter = data.crbegin();
 			auto stop = data.crend();
-			return Join([&iter, &stop]() -> const char* {
-				// if we reach tail, return nullptr
-				if (iter == stop) return nullptr;
+			return Join([&iter, &stop](yycc_u8string_view& view) -> bool {
+				// if we reach tail, return false
+				if (iter == stop) return false;
 				// otherwise fetch data, inc iterator and return.
-				const char* ret = iter->c_str();
+				view = *iter;
 				++iter;
-				return ret;
+				return true;
 				}, decilmer);
 		} else {
 			auto iter = data.cbegin();
 			auto stop = data.cend();
-			return Join([&iter, &stop]() -> const char* {
+			return Join([&iter, &stop](yycc_u8string_view& view) -> bool {
 				// if we reach tail, return nullptr
-				if (iter == stop) return nullptr;
+				if (iter == stop) return false;
 				// otherwise fetch data, inc iterator and return.
-				const char* ret = iter->c_str();
+				view = *iter;
 				++iter;
-				return ret;
+				return true;
 				}, decilmer);
 		}
 	}
 
+#pragma endregion
+
+#pragma region Upper Lower
 
 	template<bool bIsToLower>
-	void GeneralStringLowerUpper(std::string& strl) {
+	void GeneralStringLowerUpper(yycc_u8string& strl) {
 		// References:
 		// https://en.cppreference.com/w/cpp/algorithm/transform
 		// https://en.cppreference.com/w/cpp/string/byte/tolower
@@ -159,59 +183,77 @@ namespace YYCC::StringHelper {
 		);
 	}
 
-	std::string Lower(const char* strl) {
-		std::string ret;
+	yycc_u8string Lower(const yycc_char8_t* strl) {
+		yycc_u8string ret;
 		if (strl == nullptr) return ret;
 		else ret = strl;
 		Lower(ret);
 		return ret;
 	}
 
-	void Lower(std::string& strl) {
+	void Lower(yycc_u8string& strl) {
 		GeneralStringLowerUpper<true>(strl);
 	}
 
-	std::string Upper(const char* strl) {
+	yycc_u8string Upper(const yycc_char8_t* strl) {
 		// same as Lower, just replace char transform function.
-		std::string ret;
+		yycc_u8string ret;
 		if (strl == nullptr) return ret;
 		else ret = strl;
 		Upper(ret);
 		return ret;
 	}
 
-	void Upper(std::string& strl) {
+	void Upper(yycc_u8string& strl) {
 		GeneralStringLowerUpper<false>(strl);
 	}
 
-	std::vector<std::string> Split(const char* _strl, const char* _decilmer) {
+#pragma endregion
+
+#pragma region Split
+
+	std::vector<yycc_u8string> Split(const yycc_u8string_view& strl, const yycc_char8_t* _decilmer) {
+		// call split view
+		auto view_result = SplitView(strl, _decilmer);
+
+		// copy string view result to string
+		std::vector<yycc_u8string> elems;
+		for (const auto& strl_view : view_result) {
+			elems.emplace_back(yycc_u8string(strl_view));
+		}
+		// return copied result
+		return elems;
+	}
+
+	std::vector<yycc_u8string_view> SplitView(const yycc_u8string_view& strl, const yycc_char8_t* _decilmer) {
 		// Reference: 
 		// https://stackoverflow.com/questions/14265581/parse-split-a-string-in-c-using-string-delimiter-standard-c
 		
 		// prepare return value
-		std::vector<std::string> elems;
+		std::vector<yycc_u8string_view> elems;
 
-		// if the string need to be splitted is nullptr, return empty result.
-		if (_strl == nullptr) return elems;
-		std::string strl(_strl);
-		// if decilmer is nullptr, or decilmer is zero length, return original string
-		std::string decilmer;
-		if (_decilmer == nullptr || (decilmer = _decilmer, decilmer.empty())) {
-			elems.push_back(strl);
+		// if string need to be splitted is empty, return original string (empty item).
+		// if decilmer is nullptr, or decilmer is zero length, return original string.
+		yycc_u8string decilmer;
+		if (strl.empty() || _decilmer == nullptr || (decilmer = _decilmer, decilmer.empty())) {
+			elems.emplace_back(strl);
 			return elems;
 		}
 
 		// start spliting
 		std::size_t previous = 0, current;
-		while ((current = strl.find(decilmer.c_str(), previous)) != std::string::npos) {
-			elems.push_back(strl.substr(previous, current - previous));
+		while ((current = strl.find(decilmer.c_str(), previous)) != yycc_u8string::npos) {
+			elems.emplace_back(strl.substr(previous, current - previous));
 			previous = current + decilmer.size();
 		}
 		// try insert last part but prevent possible out of range exception
 		if (previous <= strl.size()) {
-			elems.push_back(strl.substr(previous));
+			elems.emplace_back(strl.substr(previous));
 		}
 		return elems;
 	}
 
+#pragma endregion
+
+
 }

src/StringHelper.hpp

@@ -8,21 +8,22 @@
 
 namespace YYCC::StringHelper {
 
-	bool Printf(std::string& strl, const char* format, ...);
-	bool VPrintf(std::string& strl, const char* format, va_list argptr);
+	bool Printf(yycc_u8string& strl, const yycc_char8_t* format, ...);
+	bool VPrintf(yycc_u8string& strl, const yycc_char8_t* format, va_list argptr);
+	yycc_u8string Printf(const yycc_char8_t* format, ...);
+	yycc_u8string VPrintf(const yycc_char8_t* format, va_list argptr);
 
-	std::string Printf(const char* format, ...);
-	std::string VPrintf(const char* format, va_list argptr);
-
-	void Replace(std::string& strl, const char* _from_strl, const char* _to_strl);
-	std::string Replace(const char* _strl, const char* _from_strl, const char* _to_strl);
+	void Replace(yycc_u8string& strl, const yycc_char8_t* _from_strl, const yycc_char8_t* _to_strl);
+	yycc_u8string Replace(const yycc_char8_t* _strl, const yycc_char8_t* _from_strl, const yycc_char8_t* _to_strl);
 
 	/**
 	 * @brief The data provider of general Join function.
-	 * This function pointer return non-null string pointer to represent a element of joined series.
-	 * otherwise return nullptr to terminate the joining process.
+	 * For the implementation of this function:
+	 * Function return true to continue join. otherwise return false to terminate join. 
+	 * The argument assigned in the calling returning false is not included.
+	 * During calling, implementation should assign the string view to the string need to be joined in given argument.
 	*/
-	using JoinDataProvider = std::function<const char* ()>;
+	using JoinDataProvider = std::function<bool(yycc_u8string_view&)>;
 	/**
 	 * @brief General Join function.
 	 * @details This function use function pointer as a general data provider interface,
@@ -31,7 +32,7 @@ namespace YYCC::StringHelper {
 	 * @param decilmer[in] The decilmer.
 	 * @return A std::string instance which containing the join result.
 	*/
-	std::string Join(JoinDataProvider fct_data, const char* decilmer);
+	yycc_u8string Join(JoinDataProvider fct_data, const yycc_char8_t* decilmer);
 	/**
 	 * @brief Specialized Join function for common used container.
 	 * @param data
@@ -39,26 +40,16 @@ namespace YYCC::StringHelper {
 	 * @param reversed
 	 * @return
 	*/
-	std::string Join(const std::vector<std::string>& data, const char* decilmer, bool reversed = false);
+	yycc_u8string Join(const std::vector<yycc_u8string>& data, const yycc_char8_t* decilmer, bool reversed = false);
 
-	/**
-	 * @brief Transform string to lower.
-	 * @param strl
-	 * @return
-	*/
-	std::string Lower(const char* strl);
-	void Lower(std::string& strl);
-	/**
-	 * @brief Transform string to upper.
-	 * @param strl
-	 * @return
-	*/
-	std::string Upper(const char* strl);
-	void Upper(std::string& strl);
+	yycc_u8string Lower(const yycc_char8_t* strl);
+	void Lower(yycc_u8string& strl);
+	yycc_u8string Upper(const yycc_char8_t* strl);
+	void Upper(yycc_u8string& strl);
 
 	/**
 	 * @brief General Split function.
-	 * @param _strl[in] The string need to be splitting.
+	 * @param strl[in] The string need to be splitting.
 	 * If this is nullptr, the result will be empty.
 	 * @param _decilmer[in] The decilmer for splitting.
 	 * If decilmer is nullptr or zero length, the result will only have 1 element which is original string.
@@ -67,5 +58,7 @@ namespace YYCC::StringHelper {
 	 * It can works in most toy cases but not suit for high performance scenario.
 	 * Also, this function will produce a copy of original string because it is not zero copy.
 	*/
-	std::vector<std::string> Split(const char* _strl, const char* _decilmer);
+	std::vector<yycc_u8string> Split(const yycc_u8string_view& strl, const yycc_char8_t* _decilmer);
+	std::vector<yycc_u8string_view> SplitView(const yycc_u8string_view& strl, const yycc_char8_t* _decilmer);
+
 }

src/WinFctHelper.cpp

@@ -17,7 +17,7 @@ namespace YYCC::WinFctHelper {
 		return hModule;
 	}
 
-	bool GetTempDirectory(std::string& ret) {
+	bool GetTempDirectory(yycc_u8string& ret) {
 		// create wchar buffer for receiving the temp path.
 		std::wstring wpath(MAX_PATH + 1u, L'\0');
 		DWORD expected_size;
@@ -41,10 +41,10 @@ namespace YYCC::WinFctHelper {
 		// resize result
 		wpath.resize(expected_size);
 		// convert to utf8 and return
-		return YYCC::EncodingHelper::WcharToUTF8(wpath.c_str(), ret);
+		return YYCC::EncodingHelper::WcharToUTF8(wpath, ret);
 	}
 
-	bool GetModuleFileName(HINSTANCE hModule, std::string& ret) {
+	bool GetModuleFileName(HINSTANCE hModule, yycc_u8string& ret) {
 		// create wchar buffer for receiving the temp path.
 		std::wstring wpath(MAX_PATH + 1u, L'\0');
 		DWORD copied_size;
@@ -68,10 +68,13 @@ namespace YYCC::WinFctHelper {
 		// resize result
 		wpath.resize(copied_size);
 		// convert to utf8 and return
-		return YYCC::EncodingHelper::WcharToUTF8(wpath.c_str(), ret);
+		return YYCC::EncodingHelper::WcharToUTF8(wpath, ret);
 	}
 
-	bool GetLocalAppData(std::string& ret) {
+	bool GetLocalAppData(yycc_u8string& ret) {
+		// check whether com initialized
+		if (!COMHelper::IsInitialized()) return false;
+
 		// fetch path
 		LPWSTR _known_path;
 		HRESULT hr = SHGetKnownFolderPath(FOLDERID_LocalAppData, KF_FLAG_CREATE, NULL, &_known_path);

src/WinFctHelper.hpp

@@ -36,7 +36,7 @@ namespace YYCC::WinFctHelper {
 	 * The variable receiving UTF8 encoded path to Windows temp folder.
 	 * @return True if success, otherwise false.
 	*/
-	bool GetTempDirectory(std::string& ret);
+	bool GetTempDirectory(yycc_u8string& ret);
 
 	/**
 	 * @brief Get the file name of given module HANDLE
@@ -47,7 +47,7 @@ namespace YYCC::WinFctHelper {
 	 * The variable receiving UTF8 encoded file name of given module.
 	 * @return True if success, otherwise false.
 	*/
-	bool GetModuleFileName(HINSTANCE hModule, std::string& ret);
+	bool GetModuleFileName(HINSTANCE hModule, yycc_u8string& ret);
 
 	/**
 	 * @brief Get the path to LOCALAPPDATA.
@@ -56,7 +56,7 @@ namespace YYCC::WinFctHelper {
 	 * The variable receiving UTF8 encoded path to LOCALAPPDATA.
 	 * @return 
 	*/
-	bool GetLocalAppData(std::string& ret);
+	bool GetLocalAppData(yycc_u8string& ret);
 
 }
 

src/YYCCInternal.hpp

@@ -24,14 +24,20 @@
 
 #endif
 
-//// Decide the char type we used
-//#include <string>
-//namespace YYCC {
-//#if defined(__cpp_char8_t)
-//	using u8char = char8_t;
-//	using u8string = std::std::string
-//#else
-//	using u8char = char;
-//	using u8string = std::string;
-//#endif
-//}
+// Define the UTF8 char type we used.
+// And do a polyfill if no embedded char8_t type.
+#include <string>
+#include <string_view>
+namespace YYCC {
+#if defined(__cpp_char8_t)
+	using yycc_char8_t = char8_t;
+	using yycc_u8string = std::u8string;
+	using yycc_u8string_view = std::u8string_view;
+#else
+	using yycc_char8_t = unsigned char;
+	using yycc_u8string = std::basic_string<yycc_char8_t>;
+	using yycc_u8string_view = std::basic_string_view<yycc_char8_t>;
+#endif
+	
+}
+

src/YYCCommonplace.hpp

@@ -2,13 +2,15 @@
 
 #include "YYCCInternal.hpp"
 
-#include "StringHelper.hpp"
 #include "EncodingHelper.hpp"
+#include "StringHelper.hpp"
 #include "ConsoleHelper.hpp"
 #include "COMHelper.hpp"
 #include "DialogHelper.hpp"
 #include "ParserHelper.hpp"
-#include "ExceptionHelper.hpp"
 #include "IOHelper.hpp"
 #include "WinFctHelper.hpp"
 #include "FsPathPatch.hpp"
+#include "ExceptionHelper.hpp"
+
+#include "ConfigManager.hpp"

testbench/main.cpp

@@ -23,12 +23,12 @@ namespace YYCCTestbench {
 #define TEST_UNICODE_STR_EMOJI "\U0001F363 \u2716 \U0001F37A" // sushi x beer mug
 
 #define CONCAT(prefix, strl) prefix ## strl
-#define CPP_U8_LITERAL(strl) reinterpret_cast<const char*>(CONCAT(u8, strl))
+#define CPP_U8_LITERAL(strl) YYCC_U8(strl)
 #define CPP_U16_LITERAL(strl) CONCAT(u, strl)
 #define CPP_U32_LITERAL(strl) CONCAT(U, strl)
 #define CPP_WSTR_LITERAL(strl) CONCAT(L, strl)
 
-	static std::vector<std::string> c_UTF8TestStrTable {
+	static std::vector<YYCC::yycc_u8string> c_UTF8TestStrTable {
 		CPP_U8_LITERAL(TEST_UNICODE_STR_JAPAN),
 		CPP_U8_LITERAL(TEST_UNICODE_STR_CHINA),
 		CPP_U8_LITERAL(TEST_UNICODE_STR_KOREA),
@@ -93,11 +93,11 @@ namespace YYCCTestbench {
 
 #pragma endregion
 
-	static void Assert(bool condition, const char* description) {
+	static void Assert(bool condition, const YYCC::yycc_char8_t* description) {
 		if (condition) {
-			Console::FormatLine(YYCC_COLOR_LIGHT_GREEN("OK: %s"), description);
+			Console::FormatLine(YYCC_U8(YYCC_COLOR_LIGHT_GREEN("OK: %s")), description);
 		} else {
-			Console::FormatLine(YYCC_COLOR_LIGHT_RED("Failed: %s\n"), description);
+			Console::FormatLine(YYCC_U8(YYCC_COLOR_LIGHT_RED("Failed: %s\n")), description);
 			std::abort();
 		}
 	}
@@ -105,9 +105,9 @@ namespace YYCCTestbench {
 	static void ConsoleTestbench() {
 		// Color Test
 		Console::EnableColorfulConsole();
-		Console::WriteLine("Color Test:");
+		Console::WriteLine(YYCC_U8("Color Test:"));
 
-#define TEST_MACRO(col) Console::WriteLine("\t" YYCC_COLOR_ ## col ("\u2588\u2588") YYCC_COLOR_LIGHT_ ## col("\u2588\u2588") " " #col " / LIGHT " #col );
+#define TEST_MACRO(col) Console::WriteLine(YYCC_U8("\t" YYCC_COLOR_ ## col ("\u2588\u2588") YYCC_COLOR_LIGHT_ ## col("\u2588\u2588") " " #col " / LIGHT " #col ));
 		// U+2588 is full block
 
 		TEST_MACRO(BLACK);
@@ -122,19 +122,19 @@ namespace YYCCTestbench {
 #undef TEST_MACRO
 
 		// UTF8 Output Test
-		Console::WriteLine("UTF8 Output Test:");
+		Console::WriteLine(YYCC_U8("UTF8 Output Test:"));
 		for (const auto& strl : c_UTF8TestStrTable) {
-			Console::FormatLine("\t%s", strl.c_str());
+			Console::FormatLine(YYCC_U8("\t%s"), strl.c_str());
 		}
 
 		// UTF8 Input Test
-		Console::WriteLine("UTF8 Input Test:");
+		Console::WriteLine(YYCC_U8("UTF8 Input Test:"));
 		for (const auto& strl : c_UTF8TestStrTable) {
-			Console::FormatLine("\tPlease type: %s", strl.c_str());
-			Console::Write("\t> ");
+			Console::FormatLine(YYCC_U8("\tPlease type: %s"), strl.c_str());
+			Console::Write(YYCC_U8("\t> "));
 
-			std::string gotten(Console::ReadLine());
-			Assert(gotten == strl, YYCC::StringHelper::Printf("Got: %s", gotten.c_str()).c_str());
+			YYCC::yycc_u8string gotten(Console::ReadLine());
+			Assert(gotten == strl, YYCC::StringHelper::Printf(YYCC_U8("Got: %s"), gotten.c_str()).c_str());
 		}
 
 	}
@@ -151,16 +151,16 @@ namespace YYCCTestbench {
 			const auto& u32str = c_UTF32TestStrTable[i];
 
 			// create cache variables
-			std::string u8cache;
+			YYCC::yycc_u8string u8cache;
 			std::u16string u16cache;
 			std::u32string u32cache;
 
 			// do convertion check
-			Assert(YYCC::EncodingHelper::UTF8ToUTF16(u8str.c_str(), u16cache) && u16cache == u16str, "YYCC::EncodingHelper::UTF8ToUTF16");
-			Assert(YYCC::EncodingHelper::UTF8ToUTF32(u8str.c_str(), u32cache) && u32cache == u32str, "YYCC::EncodingHelper::UTF8ToUTF32");
+			Assert(YYCC::EncodingHelper::UTF8ToUTF16(u8str, u16cache) && u16cache == u16str, YYCC_U8("YYCC::EncodingHelper::UTF8ToUTF16"));
+			Assert(YYCC::EncodingHelper::UTF8ToUTF32(u8str, u32cache) && u32cache == u32str, YYCC_U8("YYCC::EncodingHelper::UTF8ToUTF32"));
 
-			Assert(YYCC::EncodingHelper::UTF16ToUTF8(u16str.c_str(), u8cache) && u8cache == u8str, "YYCC::EncodingHelper::UTF16ToUTF8");
-			Assert(YYCC::EncodingHelper::UTF32ToUTF8(u32str.c_str(), u8cache) && u8cache == u8str, "YYCC::EncodingHelper::UTF32ToUTF8");
+			Assert(YYCC::EncodingHelper::UTF16ToUTF8(u16str, u8cache) && u8cache == u8str, YYCC_U8("YYCC::EncodingHelper::UTF16ToUTF8"));
+			Assert(YYCC::EncodingHelper::UTF32ToUTF8(u32str, u8cache) && u8cache == u8str, YYCC_U8("YYCC::EncodingHelper::UTF32ToUTF8"));
 		}
 
 		// check wstring convertion on windows
@@ -171,12 +171,12 @@ namespace YYCCTestbench {
 			const auto& wstr = c_WStrTestStrTable[i];
 
 			// create cache variables
-			std::string u8cache;
+			YYCC::yycc_u8string u8cache;
 			std::wstring wcache;
 
 			// do convertion check
-			Assert(YYCC::EncodingHelper::UTF8ToWchar(u8str.c_str(), wcache) && wcache == wstr, "YYCC::EncodingHelper::UTF8ToWchar");
-			Assert(YYCC::EncodingHelper::WcharToUTF8(wstr.c_str(), u8cache) && u8cache == u8str, "YYCC::EncodingHelper::WcharToUTF8");
+			Assert(YYCC::EncodingHelper::UTF8ToWchar(u8str.c_str(), wcache) && wcache == wstr, YYCC_U8("YYCC::EncodingHelper::UTF8ToWchar"));
+			Assert(YYCC::EncodingHelper::WcharToUTF8(wstr.c_str(), u8cache) && u8cache == u8str, YYCC_U8("YYCC::EncodingHelper::WcharToUTF8"));
 		}
 #endif
 
@@ -184,55 +184,58 @@ namespace YYCCTestbench {
 
 	static void StringTestbench() {
 		// Test Printf
-		auto test_printf = YYCC::StringHelper::Printf("%s == %s", "Hello World", "Hello, world");
-		Assert(test_printf == "Hello World == Hello, world", "YYCC::StringHelper::Printf");
+		auto test_printf = YYCC::StringHelper::Printf(YYCC_U8("%s == %s"), YYCC_U8("Hello World"), YYCC_U8("Hello, world"));
+		Assert(test_printf == YYCC_U8("Hello World == Hello, world"), YYCC_U8("YYCC::StringHelper::Printf"));
 
 		// Test Replace
-		auto test_replace = YYCC::StringHelper::Replace("aabbcc", "bb", "dd"); // normal case
-		Assert(test_replace == "aaddcc", "YYCC::StringHelper::Replace");
-		test_replace = YYCC::StringHelper::Replace("aabbcc", "zz", "yy"); // no replace
-		Assert(test_replace == "aabbcc", "YYCC::StringHelper::Replace");
-		test_replace = YYCC::StringHelper::Replace("aabbcc", "", "zz"); // empty finding
-		Assert(test_replace == "aabbcc", "YYCC::StringHelper::Replace");
-		test_replace = YYCC::StringHelper::Replace("aabbcc", nullptr, "zz"); // nullptr finding
-		Assert(test_replace == "aabbcc", "YYCC::StringHelper::Replace");
-		test_replace = YYCC::StringHelper::Replace("aaaabbaa", "aa", ""); // no replaced string
-		Assert(test_replace == "bb", "YYCC::StringHelper::Replace");
-		test_replace = YYCC::StringHelper::Replace("aaxcc", "x", "yx"); // nested replacing
-		Assert(test_replace == "aayxcc", "YYCC::StringHelper::Replace");
-		test_replace = YYCC::StringHelper::Replace("", "", "xy"); // empty source string
-		Assert(test_replace == "", "YYCC::StringHelper::Replace");
-		test_replace = YYCC::StringHelper::Replace(nullptr, "", "xy"); // nullptr source string
-		Assert(test_replace == "", "YYCC::StringHelper::Replace");
+		auto test_replace = YYCC::StringHelper::Replace(YYCC_U8("aabbcc"), YYCC_U8("bb"), YYCC_U8("dd")); // normal case
+		Assert(test_replace == YYCC_U8("aaddcc"), YYCC_U8("YYCC::StringHelper::Replace"));
+		test_replace = YYCC::StringHelper::Replace(YYCC_U8("aabbcc"), YYCC_U8("zz"), YYCC_U8("yy")); // no replace
+		Assert(test_replace == YYCC_U8("aabbcc"), YYCC_U8("YYCC::StringHelper::Replace"));
+		test_replace = YYCC::StringHelper::Replace(YYCC_U8("aabbcc"), YYCC_U8(""), YYCC_U8("zz")); // empty finding
+		Assert(test_replace == YYCC_U8("aabbcc"), YYCC_U8("YYCC::StringHelper::Replace"));
+		test_replace = YYCC::StringHelper::Replace(YYCC_U8("aabbcc"), nullptr, YYCC_U8("zz")); // nullptr finding
+		Assert(test_replace == YYCC_U8("aabbcc"), YYCC_U8("YYCC::StringHelper::Replace"));
+		test_replace = YYCC::StringHelper::Replace(YYCC_U8("aaaabbaa"), YYCC_U8("aa"), YYCC_U8("")); // no replaced string
+		Assert(test_replace == YYCC_U8("bb"), YYCC_U8("YYCC::StringHelper::Replace"));
+		test_replace = YYCC::StringHelper::Replace(YYCC_U8("aaxcc"), YYCC_U8("x"), YYCC_U8("yx")); // nested replacing
+		Assert(test_replace == YYCC_U8("aayxcc"), YYCC_U8("YYCC::StringHelper::Replace"));
+		test_replace = YYCC::StringHelper::Replace(YYCC_U8(""), YYCC_U8(""), YYCC_U8("xy")); // empty source string
+		Assert(test_replace == YYCC_U8(""), YYCC_U8("YYCC::StringHelper::Replace"));
+		test_replace = YYCC::StringHelper::Replace(nullptr, YYCC_U8(""), YYCC_U8("xy")); // nullptr source string
+		Assert(test_replace == YYCC_U8(""), YYCC_U8("YYCC::StringHelper::Replace"));
 
 		// Test Upper / Lower
-		auto test_lower = YYCC::StringHelper::Lower("LOWER");
-		Assert(test_lower == "lower", "YYCC::StringHelper::Lower");
-		auto test_upper = YYCC::StringHelper::Upper("upper");
-		Assert(test_upper == "UPPER", "YYCC::StringHelper::Upper");
+		auto test_lower = YYCC::StringHelper::Lower(YYCC_U8("LOWER"));
+		Assert(test_lower == YYCC_U8("lower"), YYCC_U8("YYCC::StringHelper::Lower"));
+		auto test_upper = YYCC::StringHelper::Upper(YYCC_U8("upper"));
+		Assert(test_upper == YYCC_U8("UPPER"), YYCC_U8("YYCC::StringHelper::Upper"));
 
 		// Test Join
-		std::vector<std::string> test_join_container {
-			"", "1", "2", ""
+		std::vector<YYCC::yycc_u8string> test_join_container {
+			YYCC_U8(""), YYCC_U8("1"), YYCC_U8("2"), YYCC_U8("")
 		};
-		auto test_join = YYCC::StringHelper::Join(test_join_container, ", ");
-		Assert(test_join == ", 1, 2, ", "YYCC::StringHelper::Join");
-		test_join = YYCC::StringHelper::Join(test_join_container, ", ", true);
-		Assert(test_join == ", 2, 1, ", "YYCC::StringHelper::Join");
+		auto test_join = YYCC::StringHelper::Join(test_join_container, YYCC_U8(", "));
+		Assert(test_join == YYCC_U8(", 1, 2, "), YYCC_U8("YYCC::StringHelper::Join"));
+		test_join = YYCC::StringHelper::Join(test_join_container, YYCC_U8(", "), true);
+		Assert(test_join == YYCC_U8(", 2, 1, "), YYCC_U8("YYCC::StringHelper::Join"));
 
 		// Test Split
-		auto test_split = YYCC::StringHelper::Split(", 1, 2, ", ", ");
-		Assert(test_split.size() == 4u, "YYCC::StringHelper::Split");
-		Assert(test_split[0] == "", "YYCC::StringHelper::Split");
-		Assert(test_split[1] == "1", "YYCC::StringHelper::Split");
-		Assert(test_split[2] == "2", "YYCC::StringHelper::Split");
-		Assert(test_split[3] == "", "YYCC::StringHelper::Split");
-		test_split = YYCC::StringHelper::Split("test", "-");
-		Assert(test_split.size() == 1u, "YYCC::StringHelper::Split");
-		Assert(test_split[0] == "test", "YYCC::StringHelper::Split");
-		test_split = YYCC::StringHelper::Split("test", "");
-		Assert(test_split.size() == 1u, "YYCC::StringHelper::Split");
-		Assert(test_split[0] == "test", "YYCC::StringHelper::Split");
+		auto test_split = YYCC::StringHelper::Split(YYCC_U8(", 1, 2, "), YYCC_U8(", ")); // normal
+		Assert(test_split.size() == 4u, YYCC_U8("YYCC::StringHelper::Split"));
+		Assert(test_split[0] == YYCC_U8(""), YYCC_U8("YYCC::StringHelper::Split"));
+		Assert(test_split[1] == YYCC_U8("1"), YYCC_U8("YYCC::StringHelper::Split"));
+		Assert(test_split[2] == YYCC_U8("2"), YYCC_U8("YYCC::StringHelper::Split"));
+		Assert(test_split[3] == YYCC_U8(""), YYCC_U8("YYCC::StringHelper::Split"));
+		test_split = YYCC::StringHelper::Split(YYCC_U8("test"), YYCC_U8("-")); // no matched decilmer
+		Assert(test_split.size() == 1u, YYCC_U8("YYCC::StringHelper::Split"));
+		Assert(test_split[0] == YYCC_U8("test"), YYCC_U8("YYCC::StringHelper::Split"));
+		test_split = YYCC::StringHelper::Split(YYCC_U8("test"), YYCC_U8("")); // empty decilmer
+		Assert(test_split.size() == 1u, YYCC_U8("YYCC::StringHelper::Split"));
+		Assert(test_split[0] == YYCC_U8("test"), YYCC_U8("YYCC::StringHelper::Split"));
+		test_split = YYCC::StringHelper::Split(YYCC::yycc_u8string_view(), YYCC_U8("")); // empty source string
+		Assert(test_split.size() == 1u, YYCC_U8("YYCC::StringHelper::Split"));
+		Assert(test_split[0].empty(), YYCC_U8("YYCC::StringHelper::Split"));
 
 	}
 
@@ -240,9 +243,9 @@ namespace YYCCTestbench {
 
 		// Test success TryParse
 #define TEST_MACRO(type_t, value, string_value) { \
-	std::string cache_string(string_value); \
+	YYCC::yycc_u8string cache_string(YYCC_U8(string_value)); \
 	type_t cache; \
-	Assert(YYCC::ParserHelper::TryParse<type_t>(cache_string, cache) && cache == value, "YYCC::StringHelper::TryParse<" #type_t ">"); \
+	Assert(YYCC::ParserHelper::TryParse<type_t>(cache_string, cache) && cache == value, YYCC_U8("YYCC::StringHelper::TryParse<" #type_t ">")); \
 }
 
 		TEST_MACRO(int8_t, INT8_C(-61), "-61");
@@ -259,9 +262,9 @@ namespace YYCCTestbench {
 
 		// Test failed TryParse
 #define TEST_MACRO(type_t, value, string_value) { \
-	std::string cache_string(string_value); \
+	YYCC::yycc_u8string cache_string(YYCC_U8(string_value)); \
 	type_t cache; \
-	Assert(!YYCC::ParserHelper::TryParse<type_t>(cache_string, cache), "YYCC::StringHelper::TryParse<" #type_t ">"); \
+	Assert(!YYCC::ParserHelper::TryParse<type_t>(cache_string, cache), YYCC_U8("YYCC::StringHelper::TryParse<" #type_t ">")); \
 }
 
 		TEST_MACRO(int8_t, INT8_C(-61), "6161");
@@ -279,8 +282,8 @@ namespace YYCCTestbench {
 		// Test ToString
 #define TEST_MACRO(type_t, value, string_value) { \
 	type_t cache = value; \
-	std::string ret(YYCC::ParserHelper::ToString<type_t>(cache)); \
-	Assert(ret == string_value, "YYCC::StringHelper::ToString<" #type_t ">"); \
+	YYCC::yycc_u8string ret(YYCC::ParserHelper::ToString<type_t>(cache)); \
+	Assert(ret == YYCC_U8(string_value), YYCC_U8("YYCC::StringHelper::ToString<" #type_t ">")); \
 }
 
 		TEST_MACRO(int8_t, INT8_C(-61), "-61");
@@ -292,11 +295,7 @@ namespace YYCCTestbench {
 		TEST_MACRO(int64_t, INT64_C(616161616161), "616161616161");
 		TEST_MACRO(uint64_t, UINT64_C(9223372036854775807), "9223372036854775807");
 		TEST_MACRO(bool, true, "true");
-		//{
-		//	bool cache = true;
-		//	std::string ret(YYCC::ParserHelper::ToString<bool>(cache));
-		//	Assert(ret == "true", "YYCC::StringHelper::ToString<bool>");
-		//}
+
 
 #undef TEST_MACRO
 	}
@@ -304,32 +303,32 @@ namespace YYCCTestbench {
 	static void DialogTestbench() {
 #if YYCC_OS == YYCC_OS_WINDOWS
 
-		std::string ret;
-		std::vector<std::string> rets;
+		YYCC::yycc_u8string ret;
+		std::vector<YYCC::yycc_u8string> rets;
 
 		YYCC::DialogHelper::FileDialog params;
 		auto& filters = params.ConfigreFileTypes();
-		filters.Add("Microsoft Word (*.docx; *.doc)", { "*.docx", "*.doc" });
-		filters.Add("Microsoft Excel (*.xlsx; *.xls)", { "*.xlsx", "*.xls" });
-		filters.Add("Microsoft PowerPoint (*.pptx; *.ppt)", { "*.pptx", "*.ppt" });
-		filters.Add("Text File (*.txt)", { "*.txt" });
-		filters.Add("All Files (*.*)", { "*.*" });
+		filters.Add(YYCC_U8("Microsoft Word (*.docx; *.doc)"), { YYCC_U8("*.docx"), YYCC_U8("*.doc") });
+		filters.Add(YYCC_U8("Microsoft Excel (*.xlsx; *.xls)"), { YYCC_U8("*.xlsx"), YYCC_U8("*.xls") });
+		filters.Add(YYCC_U8("Microsoft PowerPoint (*.pptx; *.ppt)"), { YYCC_U8("*.pptx"), YYCC_U8("*.ppt") });
+		filters.Add(YYCC_U8("Text File (*.txt)"), { YYCC_U8("*.txt") });
+		filters.Add(YYCC_U8("All Files (*.*)"), { YYCC_U8("*.*") });
 		params.SetDefaultFileTypeIndex(0u);
 		if (YYCC::DialogHelper::OpenFileDialog(params, ret)) {
-			Console::FormatLine("Open File: %s", ret.c_str());
+			Console::FormatLine(YYCC_U8("Open File: %s"), ret.c_str());
 		}
 		if (YYCC::DialogHelper::OpenMultipleFileDialog(params, rets)) {
-			Console::WriteLine("Open Multiple Files:");
+			Console::WriteLine(YYCC_U8("Open Multiple Files:"));
 			for (const auto& item : rets) {
-				Console::FormatLine("\t%s", item.c_str());
+				Console::FormatLine(YYCC_U8("\t%s"), item.c_str());
 			}
 		}
 		if (YYCC::DialogHelper::SaveFileDialog(params, ret)) {
-			Console::FormatLine("Save File: %s", ret.c_str());
+			Console::FormatLine(YYCC_U8("Save File: %s"), ret.c_str());
 		}
 		params.Clear();
 		if (YYCC::DialogHelper::OpenFolderDialog(params, ret)) {
-			Console::FormatLine("Open Folder: %s", ret.c_str());
+			Console::FormatLine(YYCC_U8("Open Folder: %s"), ret.c_str());
 		}
 
 #endif
@@ -353,20 +352,20 @@ namespace YYCCTestbench {
 #if YYCC_OS == YYCC_OS_WINDOWS
 
 		HMODULE test_current_module;
-		Assert((test_current_module = YYCC::WinFctHelper::GetCurrentModule()) != nullptr, "YYCC::WinFctHelper::GetCurrentModule");
-		Console::FormatLine("Current Module HANDLE: 0x%" PRI_XPTR_LEFT_PADDING PRIXPTR, test_current_module);
+		Assert((test_current_module = YYCC::WinFctHelper::GetCurrentModule()) != nullptr, YYCC_U8("YYCC::WinFctHelper::GetCurrentModule"));
+		Console::FormatLine(YYCC_U8("Current Module HANDLE: 0x%" PRI_XPTR_LEFT_PADDING PRIXPTR), test_current_module);
 
-		std::string test_temp;
-		Assert(YYCC::WinFctHelper::GetTempDirectory(test_temp), "YYCC::WinFctHelper::GetTempDirectory");
-		Console::FormatLine("Temp Directory: %s", test_temp.c_str());
+		YYCC::yycc_u8string test_temp;
+		Assert(YYCC::WinFctHelper::GetTempDirectory(test_temp), YYCC_U8("YYCC::WinFctHelper::GetTempDirectory"));
+		Console::FormatLine(YYCC_U8("Temp Directory: %s"), test_temp.c_str());
 
-		std::string test_module_name;
-		Assert(YYCC::WinFctHelper::GetModuleFileName(YYCC::WinFctHelper::GetCurrentModule(), test_module_name), "YYCC::WinFctHelper::GetModuleFileName");
-		Console::FormatLine("Current Module File Name: %s", test_module_name.c_str());
+		YYCC::yycc_u8string test_module_name;
+		Assert(YYCC::WinFctHelper::GetModuleFileName(YYCC::WinFctHelper::GetCurrentModule(), test_module_name), YYCC_U8("YYCC::WinFctHelper::GetModuleFileName"));
+		Console::FormatLine(YYCC_U8("Current Module File Name: %s"), test_module_name.c_str());
 
-		std::string test_localappdata_path;
-		Assert(YYCC::WinFctHelper::GetLocalAppData(test_localappdata_path), "YYCC::WinFctHelper::GetLocalAppData");
-		Console::FormatLine("Local AppData: %s", test_localappdata_path.c_str());
+		YYCC::yycc_u8string test_localappdata_path;
+		Assert(YYCC::WinFctHelper::GetLocalAppData(test_localappdata_path), YYCC_U8("YYCC::WinFctHelper::GetLocalAppData"));
+		Console::FormatLine(YYCC_U8("Local AppData: %s"), test_localappdata_path.c_str());
 
 #endif
 	}
@@ -377,29 +376,126 @@ namespace YYCCTestbench {
 		for (const auto& strl : c_UTF8TestStrTable) {
 			test_path /= YYCC::FsPathPatch::FromUTF8Path(strl.c_str());
 		}
-		std::string test_slashed_path(YYCC::FsPathPatch::ToUTF8Path(test_path));
+		YYCC::yycc_u8string test_slashed_path(YYCC::FsPathPatch::ToUTF8Path(test_path));
 
 #if YYCC_OS == YYCC_OS_WINDOWS
 		std::wstring wdecilmer(1u, std::filesystem::path::preferred_separator);
-		std::string decilmer(YYCC::EncodingHelper::WcharToUTF8(wdecilmer.c_str()));
+		YYCC::yycc_u8string decilmer(YYCC::EncodingHelper::WcharToUTF8(wdecilmer.c_str()));
 #else
-		std::string decilmer(1u, std::filesystem::path::preferred_separator);
+		YYCC::yycc_u8string decilmer(1u, std::filesystem::path::preferred_separator);
 #endif
-		std::string test_joined_path(YYCC::StringHelper::Join(c_UTF8TestStrTable, decilmer.c_str()));
+		YYCC::yycc_u8string test_joined_path(YYCC::StringHelper::Join(c_UTF8TestStrTable, decilmer.c_str()));
 
-		Assert(test_slashed_path == test_joined_path, "YYCC::FsPathPatch");
+		Assert(test_slashed_path == test_joined_path, YYCC_U8("YYCC::FsPathPatch"));
 
 	}
 
+	class TestConfigManager {
+	public:
+		enum class TestEnum : int8_t {
+			Test1, Test2, Test3
+		};
+
+		TestConfigManager() :
+			m_IntSetting(YYCC_U8("int-setting"), INT32_C(0)),
+			m_FloatSetting(YYCC_U8("float-setting"), 0.0f),
+			m_StringSetting(YYCC_U8("string-setting"), YYCC_U8("")),
+			m_BoolSetting(YYCC_U8("bool-setting"), false),
+			m_ClampedFloatSetting(YYCC_U8("clamped-float-setting"), 0.0f, YYCC::ConfigManager::ConstrainPresets::GetNumberRangeConstrain<float>(-1.0f, 1.0f)),
+			m_EnumSetting(YYCC_U8("enum-setting"), TestEnum::Test1),
+			m_CoreManager(YYCC_U8("test.cfg"), UINT64_C(0), {
+				&m_IntSetting, &m_FloatSetting, &m_StringSetting, &m_BoolSetting, &m_ClampedFloatSetting, &m_EnumSetting
+			})
+		{}
+		~TestConfigManager() {}
+
+		void PrintSettings() {
+			Console::WriteLine(YYCC_U8("Config Manager Settings:"));
+
+			Console::FormatLine(YYCC_U8("\tint-setting: %" PRIi32), m_IntSetting.Get());
+			Console::FormatLine(YYCC_U8("\tfloat-setting: %f"), m_FloatSetting.Get());
+			Console::FormatLine(YYCC_U8("\tstring-setting: %s"), m_StringSetting.Get().c_str());
+
+			Console::FormatLine(YYCC_U8("\tbool-setting: %s"), m_BoolSetting.Get() ? YYCC_U8("true") : YYCC_U8("false"));
+			Console::FormatLine(YYCC_U8("\tfloat-setting: %f"), m_ClampedFloatSetting.Get());
+			Console::FormatLine(YYCC_U8("\tenum-setting: %" PRIi8), static_cast<std::underlying_type_t<TestEnum>>(m_EnumSetting.Get()));
+		}
+
+		YYCC::ConfigManager::NumberSetting<int32_t> m_IntSetting;
+		YYCC::ConfigManager::NumberSetting<float> m_FloatSetting;
+		YYCC::ConfigManager::StringSetting m_StringSetting;
+
+		YYCC::ConfigManager::NumberSetting<bool> m_BoolSetting;
+		YYCC::ConfigManager::NumberSetting<float> m_ClampedFloatSetting;
+		YYCC::ConfigManager::NumberSetting<TestEnum> m_EnumSetting;
+
+		YYCC::ConfigManager::CoreManager m_CoreManager;
+	};
+
+	static void ConfigManagerTestbench() {
+		// init cfg manager
+		TestConfigManager test;
+
+		// test constrain works
+		Assert(!test.m_ClampedFloatSetting.Set(2.0f), YYCC_U8("YYCC::ConfigManager::Constraint"));
+		Assert(test.m_ClampedFloatSetting.Get() == 0.0f, YYCC_U8("YYCC::ConfigManager::Constraint"));
+
+		// test modify settings
+#define TEST_MACRO(member_name, set_val) { \
+	Assert(test.member_name.Set(set_val), YYCC_U8("YYCC::ConfigManager::AbstractSetting::Set")); \
+	Assert(test.member_name.Get() == set_val, YYCC_U8("YYCC::ConfigManager::AbstractSetting::Set")); \
+}
+
+		TEST_MACRO(m_IntSetting, INT32_C(114));
+		TEST_MACRO(m_FloatSetting, 2.0f);
+		TEST_MACRO(m_StringSetting, YYCC_U8("fuck"));
+		TEST_MACRO(m_BoolSetting, true);
+		TEST_MACRO(m_ClampedFloatSetting, 0.5f);
+		TEST_MACRO(m_EnumSetting, TestConfigManager::TestEnum::Test2);
+
+#undef TEST_MACRO
+		
+		// test save
+		test.PrintSettings();
+		Assert(test.m_CoreManager.Save(), YYCC_U8("YYCC::ConfigManager::CoreManager::Save"));
+
+		// test reset
+		test.m_CoreManager.Reset();
+		test.PrintSettings();
+		Assert(test.m_IntSetting.Get() == INT32_C(0), YYCC_U8("YYCC::ConfigManager::CoreManager::Reset"));
+		Assert(test.m_FloatSetting.Get() == 0.0f, YYCC_U8("YYCC::ConfigManager::CoreManager::Reset"));
+		Assert(test.m_StringSetting.Get() == YYCC_U8(""), YYCC_U8("YYCC::ConfigManager::CoreManager::Reset"));
+		Assert(test.m_BoolSetting.Get() == false, YYCC_U8("YYCC::ConfigManager::CoreManager::Reset"));
+		Assert(test.m_ClampedFloatSetting.Get() == 0.0f, YYCC_U8("YYCC::ConfigManager::CoreManager::Reset"));
+		Assert(test.m_EnumSetting.Get() == TestConfigManager::TestEnum::Test1, YYCC_U8("YYCC::ConfigManager::CoreManager::Reset"));
+
+		// test load
+		Assert(test.m_CoreManager.Load(), YYCC_U8("YYCC::ConfigManager::CoreManager::Load"));
+		test.PrintSettings();
+		Assert(test.m_IntSetting.Get() == INT32_C(114), YYCC_U8("YYCC::ConfigManager::CoreManager::Load"));
+		Assert(test.m_FloatSetting.Get() == 2.0f, YYCC_U8("YYCC::ConfigManager::CoreManager::Load"));
+		Assert(test.m_StringSetting.Get() == YYCC_U8("fuck"), YYCC_U8("YYCC::ConfigManager::CoreManager::Load"));
+		Assert(test.m_BoolSetting.Get() == true, YYCC_U8("YYCC::ConfigManager::CoreManager::Load"));
+		Assert(test.m_ClampedFloatSetting.Get() == 0.5f, YYCC_U8("YYCC::ConfigManager::CoreManager::Load"));
+		Assert(test.m_EnumSetting.Get() == TestConfigManager::TestEnum::Test2, YYCC_U8("YYCC::ConfigManager::CoreManager::Load"));
+		
+	}
+
 }
 
 int main(int argc, char** args) {
-	//YYCCTestbench::ConsoleTestbench();
+	// common testbench
+	// normal
 	YYCCTestbench::EncodingTestbench();
 	YYCCTestbench::StringTestbench();
 	YYCCTestbench::ParserTestbench();
-	YYCCTestbench::DialogTestbench();
-	YYCCTestbench::ExceptionTestbench();
 	YYCCTestbench::WinFctTestbench();
 	YYCCTestbench::FsPathPatch();
+	// advanced
+	YYCCTestbench::ConfigManagerTestbench();
+
+	// testbench which may terminal app or ordering input
+	YYCCTestbench::ConsoleTestbench();
+	YYCCTestbench::DialogTestbench();
+	YYCCTestbench::ExceptionTestbench();
 }