feat: finish FileFilters class in dialog helper.

- finish FileFilters class representing the file types area in popup dialog.

src/DialogHelper.cpp

@@ -2,9 +2,81 @@
 #if YYCC_OS == YYCC_OS_WINDOWS
 
 #include "EncodingHelper.hpp"
+#include "StringHelper.hpp"
 
 namespace YYCC::DialogHelper {
 
+#pragma region FileFilters
+
+	bool FileFilters::Add(const char* filter_name, std::initializer_list<const char*> il) {
+		// assign filter name
+		if (filter_name == nullptr) return false;
+		FilterName name(filter_name);
+
+		// assign filter patterns
+		FilterModes modes;
+		for (const char* pattern : il) {
+			if (pattern != nullptr) modes.emplace_back(std::string(pattern));
+		}
+
+		// check filter patterns
+		if (modes.empty()) return false;
+
+		// add into pairs and return
+		m_Filters.emplace_back(std::make_pair(name, modes));
+		return true;
+	}
+
+	void FileFilters::Clear() {
+		m_Filters.clear();
+	}
+
+	bool FileFilters::Generate(UINT& filter_count, COMDLG_FILTERSPEC*& filter_specs) {
+		// init defualt value to prevent the scenario that caller do not check return value.
+		filter_count = 0u;
+		filter_specs = nullptr;
+
+		// clear win string vector and build new one
+		m_WinFilters.clear();
+		for (const auto& it : m_Filters) {
+			// convert name to wchar
+			WinFilterName name;
+			if (!YYCC::EncodingHelper::UTF8ToWchar(it.first.c_str(), name))
+				return false;
+
+			// convert pattern and join them
+			std::string joined_modes(YYCC::StringHelper::Join(it.second, u8";"));
+			WinFilterModes modes;
+			if (!YYCC::EncodingHelper::UTF8ToWchar(joined_modes.c_str(), modes))
+				return false;
+
+			// append new pair
+			m_WinFilters.emplace_back(std::make_pair(name, modes));
+		}
+
+		// check filter size
+		// if it overflow the maximum value, return false
+		size_t count = m_WinFilters.size();
+		if (count > std::numeric_limits<UINT>::max())
+			return false;
+
+		// create new win data struct
+		// and assign string pointer from internal built win string vector.
+		m_WinDataStruct.reset(new COMDLG_FILTERSPEC[count]);
+		for (size_t i = 0u; i < count; ++i) {
+			m_WinDataStruct[i].pszName = m_WinFilters[i].first.c_str();
+			m_WinDataStruct[i].pszSpec = m_WinFilters[i].second.c_str();
+		}
+
+		// set return value
+		filter_count = static_cast<UINT>(count);
+		filter_specs = m_WinDataStruct.get();
+		return true;
+	}
+
+#pragma endregion
+
+
 	//template<bool TIsOpen, bool TMultiSelection>
 	//bool GeneralFileDialog(const FileDialogParameter& params, std::vector<std::string>& ret) {
 	//	// make sure multi-selection only available in open mode

src/DialogHelper.hpp

@@ -4,6 +4,8 @@
 
 #include <string>
 #include <vector>
+#include <initializer_list>
+#include <memory>
 
 #include "WinImportPrefix.hpp"
 #include <Windows.h>
@@ -13,6 +15,57 @@
 
 namespace YYCC::DialogHelper {
 
+	/**
+	 * @brief The class represent the file types region in file dialog.
+	*/
+	class FileFilters {
+	public:
+		FileFilters() : 
+			m_Filters(),
+			m_WinFilters(), m_WinDataStruct(nullptr)
+		{}
+
+		/**
+		 * @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.
+		 * 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);
+		/**
+		 * @brief Clear filter pairs for following re-use.
+		*/
+		void Clear();
+
+		/**
+		 * @brief Generate Windows dialog system used data struct.
+		 * @param filter_count[out] The count of generated filter data struct.
+		 * @param filter_specs[out] The pointer to generated filter data struct.
+		 * @remarks User should not call this function. This function is used by internal functions.
+		 * @return True if generation is success, otherwise false.
+		*/
+		bool Generate(UINT& filter_count, COMDLG_FILTERSPEC*& filter_specs);
+
+	protected:
+		using FilterModes = std::vector<std::string>;
+		using FilterName = std::string;
+		using FilterPair = std::pair<FilterName, FilterModes>;
+
+		std::vector<FilterPair> m_Filters;
+
+		using WinFilterModes = std::wstring;
+		using WinFilterName = std::wstring;
+		using WinFilterPair = std::pair<WinFilterName, WinFilterModes>;
+
+		std::vector<WinFilterPair> m_WinFilters;
+		std::unique_ptr<COMDLG_FILTERSPEC[]> m_WinDataStruct;
+	};
+
 	//struct FileDialogParameter {
 	//	FileDialogParameter() :
 	//		m_Owner(nullptr),

src/YYCCommonplace.hpp

@@ -5,3 +5,4 @@
 #include "StringHelper.hpp"
 #include "EncodingHelper.hpp"
 #include "TerminalHelper.hpp"
+#include "DialogHelper.hpp"

testbench/main.cpp

@@ -52,9 +52,23 @@ namespace Testbench {
 
 	}
 
+	static void DialogTestbench() {
+		YYCC::DialogHelper::FileFilters test;
+		test.Add("Microsoft Word (*.docx; *.doc)", {"*.docx", "*.doc"});
+		test.Add("Microsoft Excel (*.xlsx; *.xls)", {"*.xlsx", "*.xls"});
+		test.Add("Microsoft PowerPoint (*.pptx; *.ppt)", {"*.pptx", "*.ppt"});
+		test.Add("Text File (*.*)", {"*.txt"});
+		test.Add("All Files (*.*)", {"*.*"});
+
+		UINT count;
+		COMDLG_FILTERSPEC* specs;
+		bool ret = test.Generate(count, specs);
+	}
+
 }
 
 int main(int argc, char** args) {
 	Testbench::TerminalTestbench();
 	Testbench::StringTestbench();
+	Testbench::DialogTestbench();
 }