Optimization in Get_Map_Preview_Image

[xezon]

Image *Get_Map_Preview_Image(Utf8String map_name)
{
    if (g_theWriteableGlobalData == nullptr) {
        return nullptr;
    }

    captainslog_debug("%s Map Name ", map_name.Str());
    Utf8String map_image(map_name);
    Utf8String image_file;
    Utf8String image_name;
    Utf8String str4;
    map_image.Remove_Last_Char();
    map_image.Remove_Last_Char();
    map_image.Remove_Last_Char();
    map_image.Remove_Last_Char();
    image_file = map_image;
    str4 = map_image.Reverse_Find('\\') + 1;
    str4.Concat(".tga");
    map_image.Concat(".tga");
    Utf8String portable_map_path = g_theGameState->Real_To_Portable_Map_Path(image_file);
    image_name.Set(Utf8String::s_emptyString);

    for (int i = 0; i < portable_map_path.Get_Length(); i++) {
        char c = portable_map_path.Get_Char(i);

        if (c == '\\' || c == ':') {
            image_name.Concat('_');
        } else {
            image_name.Concat(c);
        }
    }

    image_file = image_name;
    image_file.Concat(".tga");
    Image *image = g_theMappedImageCollection->Find_Image_By_Name(image_name);

    if (image == nullptr) {
        if (!g_theFileSystem->Does_File_Exist(map_image.Str())) {
            return nullptr;
        }

        Utf8String preview_image;
        preview_image.Format("%sMapPreviews/", g_theWriteableGlobalData->Get_Path_User_Data().Str());
        g_theFileSystem->Create_Directory(preview_image);
        preview_image += image_file;
        Copy_From_Big_To_Dir(map_image, preview_image);

        image = new Image();
        image->Set_Name(image_name);
        image->Set_Filename(image_file);
        image->Set_Status(0);

        Region2D region;
        region.hi.x = 1.0f;
        region.hi.y = 1.0f;
        region.lo.x = 0.0f;
        region.lo.y = 0.0f;
        image->Set_UV_Region(&region);

        image->Set_Texture_Height(128);
        image->Set_Texture_Width(128);
        g_theMappedImageCollection->Add_Image(image);
    }

    return image;
}

str4 is never used. Can be removed.