text: /*
   *  Copyright 2019-2021 Diligent Graphics LLC
   *  Copyright 2015-2019 Egor Yusov
   *
   *  Licensed under the Apache License, Version 2.0 (the "License");
   *  you may not use this file except in compliance with the License.
   *  You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   *  Unless required by applicable law or agreed to in writing, software
   *  distributed under the License is distributed on an "AS IS" BASIS,
   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   *  See the License for the specific language governing permissions and
   *  limitations under the License.
   *
   *  In no event and under no legal theory, whether in tort (including negligence),
   *  contract, or otherwise, unless required by applicable law (such as deliberate
   *  and grossly negligent acts) or agreed to in writing, shall any Contributor be
   *  liable for any damages, including any direct, indirect, special, incidental,
   *  or consequential damages of any character arising as a result of this License or
   *  out of the use or inability to use the software (including but not limited to damages
   *  for loss of goodwill, work stoppage, computer failure or malfunction, or any and
   *  all other commercial damages or losses), even if such Contributor has been advised
   *  of the possibility of such damages.
   */
  
  #include "BasicFileSystem.hpp"
  #include "DebugUtilities.hpp"
  #include <algorithm>
  
  Diligent::String BasicFileSystem::m_strWorkingDirectory;
  
  BasicFile::BasicFile(const FileOpenAttribs& OpenAttribs, Diligent::Char SlashSymbol) :
      m_OpenAttribs{OpenAttribs},
      m_Path{BasicFileSystem::GetFullPath(OpenAttribs.strFilePath)}
  {
      BasicFileSystem::CorrectSlashes(m_Path, SlashSymbol);
  
      m_OpenAttribs.strFilePath = m_Path.c_str();
  }
  
  BasicFile::~BasicFile()
  {
  }
  
  Diligent::String BasicFile::GetOpenModeStr()
  {
      std::string OpenModeStr;
      switch (m_OpenAttribs.AccessMode)
      {
          // clang-format off
          case EFileAccessMode::Read:      OpenModeStr += 'r'; break;
          case EFileAccessMode::Overwrite: OpenModeStr += 'w'; break;
          case EFileAccessMode::Append:    OpenModeStr += 'a'; break;
          // clang-format on
          default: break;
      }
  
      // Always open file in binary mode. Text mode is platform-specific
      OpenModeStr += 'b';
  
      return OpenModeStr;
  }
  
  
  std::string BasicFileSystem::GetFullPath(const Diligent::Char* strFilePath)
  {
      std::string FullPath = m_strWorkingDirectory;
      auto        len      = FullPath.length();
      if (len > 0 && FullPath[len - 1] != '\\')
      {
          FullPath += '\\';
      }
      FullPath += strFilePath;
      return FullPath;
  }
  
  BasicFile* BasicFileSystem::OpenFile(FileOpenAttribs& OpenAttribs)
  {
      return nullptr;
  }
  
  void BasicFileSystem::ReleaseFile(BasicFile* pFile)
  {
      if (pFile)
          delete pFile;
  }
  
  bool BasicFileSystem::FileExists(const Diligent::Char* strFilePath)
  {
      return false;
  }
  
  Diligent::Char BasicFileSystem::GetSlashSymbol()
  {
      UNSUPPORTED("Unsupported");
      return 0;
  }
  
  void BasicFileSystem::CorrectSlashes(Diligent::String& Path, Diligent::Char SlashSymbol)
  {
      VERIFY(SlashSymbol == '\\' || SlashSymbol == '/',
             "Incorrect slash symbol");
      Diligent::Char RevSlashSym = (SlashSymbol == '\\') ? '/' : '\\';
      std::replace(Path.begin(), Path.end(), RevSlashSym, SlashSymbol);
  }
  
  void BasicFileSystem::SplitFilePath(const Diligent::String& FullName,
                                      Diligent::String*       Path,
                                      Diligent::String*       Name)
  {
      auto LastSlashPos = FullName.find_last_of("/\\");
      if (Path)
      {
          if (LastSlashPos != Diligent::String::npos)
              *Path = FullName.substr(0, LastSlashPos);
          else
              *Path = "";
      }
  
      if (Name)
      {
          if (LastSlashPos != Diligent::String::npos)
              *Name = FullName.substr(LastSlashPos + 1);
          else
              *Name = FullName;
      }
  }
  
  bool BasicFileSystem::IsPathAbsolute(const Diligent::Char* strPath)
  {
      if (strPath == nullptr || strPath[0] == 0)
          return false;
  
  #if PLATFORM_WIN32 || PLATFORM_UNIVERSAL_WINDOWS
      return strPath[1] == ':' && (strPath[2] == '\\' || strPath[2] == '/');
  #elif PLATFORM_LINUX || PLATFORM_MACOS || PLATFORM_IOS || PLATFORM_TVOS || PLATFORM_ANDROID
      return strPath[0] == '/';
  #else
  #    error Unknown platform.
  #endif
  }
  
  std::string BasicFileSystem::SimplifyPath(const Diligent::Char* Path, Diligent::Char SlashSymbol)
  {
      if (Path == nullptr)
          return "";
  
      auto IsSlash = [](const Diligent::Char c) {
          return c == '/' || c == '\\';
      };
  
      std::vector<std::string> PathComponents;
  
      const auto* c = Path;
      while (*c != '\0')
      {
          while (*c != '\0' && IsSlash(*c))
              ++c;
  
          if (*c == '\0')
          {
              // a/
              break;
          }
  
          std::string PathCmp;
          while (*c != '\0' && !IsSlash(*c))
              PathCmp.push_back(*(c++));
  
          if (PathCmp == ".")
          {
              // Skip /.
              continue;
          }
          else if (PathCmp == ".." && !PathComponents.empty() && PathComponents.back() != "..")
          {
              // Pop previous subdirectory if /.. is found, but only if there is no .. already
              PathComponents.pop_back();
          }
          else
          {
              PathComponents.emplace_back(std::move(PathCmp));
          }
      }
  
      std::string SimplifiedPath;
      for (const auto& Cmp : PathComponents)
      {
          if (!SimplifiedPath.empty())
              SimplifiedPath.push_back(SlashSymbol);
          SimplifiedPath.append(Cmp);
      }
      return SimplifiedPath;
  }
  