text: // ----------------------------------------------------------------------------
  // -                        Open3D: www.open3d.org                            -
  // ----------------------------------------------------------------------------
  // The MIT License (MIT)
  //
  // Copyright (c) 2018 www.open3d.org
  //
  // Permission is hereby granted, free of charge, to any person obtaining a copy
  // of this software and associated documentation files (the "Software"), to deal
  // in the Software without restriction, including without limitation the rights
  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  // copies of the Software, and to permit persons to whom the Software is
  // furnished to do so, subject to the following conditions:
  //
  // The above copyright notice and this permission notice shall be included in
  // all copies or substantial portions of the Software.
  //
  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  // FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  // IN THE SOFTWARE.
  // ----------------------------------------------------------------------------
  
  #include "LineSetIO.h"
  
  #include <unordered_map>
  #include <Core/Utility/Console.h>
  #include <Core/Utility/FileSystem.h>
  
  namespace open3d {
  
  namespace {
  
  static const std::unordered_map<
          std::string,
          std::function<bool(const std::string &, LineSet &)>>
          file_extension_to_lineset_read_function{
                  {"ply", ReadLineSetFromPLY},
          };
  
  static const std::unordered_map<
          std::string,
          std::function<bool(
                  const std::string &, const LineSet &, const bool, const bool)>>
          file_extension_to_lineset_write_function{
                  {"ply", WriteLineSetToPLY},
          };
  }  // unnamed namespace
  
  std::shared_ptr<LineSet> CreateLineSetFromFile(const std::string &filename,
                                                 const std::string &format) {
      auto lineset = std::make_shared<LineSet>();
      ReadLineSet(filename, *lineset, format);
      return lineset;
  }
  
  bool ReadLineSet(const std::string &filename,
                   LineSet &lineset,
                   const std::string &format) {
      std::string filename_ext;
      if (format == "auto") {
          filename_ext = filesystem::GetFileExtensionInLowerCase(filename);
      } else {
          filename_ext = format;
      }
      if (filename_ext.empty()) {
          PrintWarning("Read LineSet failed: unknown file extension.\n");
          return false;
      }
      auto map_itr = file_extension_to_lineset_read_function.find(filename_ext);
      if (map_itr == file_extension_to_lineset_read_function.end()) {
          PrintWarning("Read LineSet failed: unknown file extension.\n");
          return false;
      }
      bool success = map_itr->second(filename, lineset);
      PrintDebug("Read LineSet: %d vertices.\n", (int)lineset.points_.size());
      return success;
  }
  
  bool WriteLineSet(const std::string &filename,
                    const LineSet &lineset,
                    bool write_ascii /* = false*/,
                    bool compressed /* = false*/) {
      std::string filename_ext =
              filesystem::GetFileExtensionInLowerCase(filename);
      if (filename_ext.empty()) {
          PrintWarning("Write LineSet failed: unknown file extension.\n");
          return false;
      }
      auto map_itr = file_extension_to_lineset_write_function.find(filename_ext);
      if (map_itr == file_extension_to_lineset_write_function.end()) {
          PrintWarning("Write LineSet failed: unknown file extension.\n");
          return false;
      }
      bool success = map_itr->second(filename, lineset, write_ascii, compressed);
      PrintDebug("Write LineSet: %d vertices.\n", (int)lineset.points_.size());
      return success;
  }
  
  }  // namespace open3d
  