doc: add documentation for win fct helper

- add documentation for win fct helper
- add new macro YYCC_U8_CHAR for casting ordinary char to yycc utf8 char.
- add documentation for new added YYCC_U8_CHAR.

doc/src/index.dox

@@ -54,6 +54,8 @@
 
     \li \subpage dialog_helper
 
+    \li \subpage win_fct_helper
+
     \li \subpage exception_helper
 
   </TD>

doc/src/library_encoding.dox

@@ -96,6 +96,24 @@ 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__char Single Char
+
+Same as UTF8 literal, YYCC allow you cast normal \c char into \c yycc_char8_t as following code:
+
+\code
+YYCC_U8_CHAR('A')
+\endcode
+
+YYCC_U8_CHAR is a macro.
+It just simply use \c static_cast to cast given value to \c yycc_char8_t.
+It doesn't mean that you can cast non-ASCII characters,
+because the space these characters occupied usually more than the maximum value of \c char.
+For example, following code is \b invalid:
+
+\code
+YYCC_U8_CHAR('文') // INVALID!
+\endcode
+
 \subsection library_encoding__utf8_literal__concatenation Literal Concatenation
 
 YYCC_U8 macro also works for string literal concatenation:

doc/src/win_fct_helper.dox

@@ -0,0 +1,17 @@
+/**
+
+\page win_fct_helper Windows Function Helper
+
+This helper give a more convenient way to call Windows functions.
+
+This namespace is Windows specific.
+It will be entirely invisible in other platforms.
+
+Currently this namespace has following functions:
+
+\li YYCC::WinFctHelper::GetCurrentModule: Get the handle to current module.
+\li YYCC::WinFctHelper::GetTempDirectory: Get temporary directory in Windows.
+\li YYCC::WinFctHelper::GetModuleFileName: Get the path to module in file system by given handle.
+\li YYCC::WinFctHelper::GetLocalAppData: Get the path inside \%LOCALAPPDATA\%
+
+*/

src/EncodingHelper.hpp

@@ -19,6 +19,7 @@ namespace YYCC::EncodingHelper {
 
 #define _YYCC_U8(strl) u8 ## strl ///< The assistant macro for YYCC_U8.
 #define YYCC_U8(strl) (reinterpret_cast<const ::YYCC::yycc_char8_t*>(_YYCC_U8(strl))) ///< The macro for creating UTF8 string literal. See \ref library_encoding.
+#define YYCC_U8_CHAR(chr) (static_cast<YYCC::yycc_char8_t>(chr)) ///< The macro for casting normal char into YYCC UTF8 char type.
 
 	const yycc_char8_t* ToUTF8(const char* src);
 	yycc_char8_t* ToUTF8(char* src);

src/FsPathPatch.hpp

@@ -3,23 +3,6 @@
 
 #include <filesystem>
 
-/**
- * @brief The patch namespace resolving \c std::filesystem::path encoding issue.
- * @details
- * This patch is Windows oriented.
- * If you are in Windows, this patch will perform extra operations to achieve goals,
- * and in other platforms, they just redirect request to corresponding vanilla C++ functions.
- * 
- * As you know, the underlying char type of \c std::filesystem::path is \c wchar_t on Windows,
- * and in other platforms, it is simple \c char.
- * Due to this, if you passing UTF8 char sequence to \c std::filesystem::path on Windows,
- * the library implementation will assume your input is based on current Windows code page, not UTF8.
- * And the final path stored in \c std::filesystem::path is not what you expcected.
- * 
- * This patch namespace always use UTF8 as its argument. There is no ambiguous issue.
- * You should use the functions provided by this namespace on any platforms 
- * instead of vanilla \c std::filesystem::path functions.
-*/
 namespace YYCC::FsPathPatch {
 	
 	/**