SVOWriter.ih

/**
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Lesser General Public License as
 *  published by the Free Software Foundation, either version 3 of the
 *  License, or  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 **/
 
#pragma once
 
/**
 * @file SVOWriter.ih
 * @author Bastien Doignies (bastien.doignies@liris.cnrs.fr)
 * Laboratoire d'InfoRmatique en Image et Systèmes d'information - LIRIS (CNRS, UMR 5205), CNRS, France
 *
 * @date 2025/10/20
 *
 * This file is part of the DGtal library.
 */
 
#include <boost/iostreams/filtering_stream.hpp>
 
namespace DGtal 
{
  template<typename Stream, typename Int>
  static inline void writeBinInt(Stream& stream, Int i) 
  {
    boost::endian::native_to_little_inplace(i); 
    stream.write(reinterpret_cast<const char*>(&i), sizeof(Int));
  }
 
  template<class Space>
  bool SVOWriter<Space>::exportSVO(const std::string& filename, const DigitalSetByOctree<Space>& octree, bool compressed) 
  {
    using Octree = DigitalSetByOctree<Space>;
    
    std::ofstream out(filename.c_str(), std::ios_base::out | std::ios::binary);
    if (!out) {
      trace.error() << "Can't open file '" << filename << "'" << std::endl;
      throw IOException{};
    }
 
    // Header:
    // Even if binary is specified, flux operator writes integer in ascii format.
    out << "Format: SVO\n";
    out << "Version: 1\n";
    out << "Size: " << static_cast<uint64_t>(octree.size()) << '\n';
    out << "Dim: " << Octree::dimension << '\n';
    out << "LowerBound:";
    for (size_t i = 0; i < Space::dimension; ++i)
      out << " " << octree.domain().lowerBound()[i];
    out << '\n';
    out << "UpperBound:";
    for (size_t i = 0; i < Space::dimension; ++i)
      out << " " << octree.domain().upperBound()[i];
    out << "\n";
    out << "State: " << static_cast<uint64_t>(octree.myState) << '\n';
    out << "Compression: " << compressed << '\n';
    out << ".\n";
 
    const auto& nodes = octree.myNodes;
 
    boost::iostreams::filtering_ostream outData;
 
    if (compressed) outData.push(boost::iostreams::zlib_compressor(boost::iostreams::zlib::best_compression));
    outData.push(out);
 
    // Technical data of current implementation
    writeBinInt(outData, static_cast<int64_t>(sizeof(typename Octree::Size)));
    writeBinInt(outData, static_cast<int64_t>(sizeof(typename Octree::CellIndex)));
 
    writeBinInt(outData, (typename Octree::Size)nodes.size());
    for (size_t i = 0; i < nodes.size(); ++i) 
      writeBinInt(outData, (typename Octree::Size)nodes[i].size());
 
    for (size_t i = 0; i < nodes.size(); ++i) 
      for (size_t j = 0; j < nodes[i].size(); ++j) 
        for (size_t k = 0; k < Octree::CELL_COUNT; ++k) 
          writeBinInt(outData, nodes[i][j].children[k]);
 
    return true;
  }
}