write garbage

- fix PathManager nullptr assign issue
- fix Context set encoding unexpected copy issue
- write some export function for BMap.

BMap/BMExports.cpp

@@ -22,3 +22,42 @@ void BMDispose() {
 	// unregister iron pad
 	IronPad::IronPadUnregister();
 }
+
+BMap::BMFile* BMFile_Load(LibCmo::CKSTRING file_name, LibCmo::CKSTRING temp_folder, LibCmo::CKSTRING texture_folder, LibCmo::CKDWORD encoding_count, LibCmo::CKSTRING encodings[]) {
+	auto file = new BMap::BMFile(temp_folder, texture_folder, encoding_count, encodings, false);
+	if (file->IsFailed()) {
+		delete file;
+		file = nullptr;
+	}
+	if (!file->Load(file_name)) {
+		delete file;
+		file = nullptr;
+	}
+
+	g_AllBMFiles.emplace(file);
+	return file;
+}
+
+BMap::BMFile* BMFile_Create(LibCmo::CKSTRING temp_folder, LibCmo::CKSTRING texture_folder, LibCmo::CKDWORD encoding_count, LibCmo::CKSTRING encodings[]) {
+	auto file = new BMap::BMFile(temp_folder, texture_folder, encoding_count, encodings, false);
+	if (file->IsFailed()) {
+		delete file;
+		file = nullptr;
+	}
+
+	g_AllBMFiles.emplace(file);
+	return file;
+}
+
+bool BMFile_Save(BMap::BMFile* map_file, LibCmo::CKSTRING file_name, LibCmo::CKINT compreess_level) {
+	if (!g_AllBMFiles.contains(map_file)) return false;
+	return map_file->Save(file_name, compreess_level);
+}
+
+void BMFile_Free(BMap::BMFile* map_file) {
+	// only free correct pointer
+	if (map_file == nullptr) return;
+	if (g_AllBMFiles.erase(map_file) != 0) {
+		delete map_file;
+	}
+}