endian.hpp

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/*
   This file is part of PLYwoot, a header-only PLY parser.
 
   Copyright (C) 2023-2025, Ton van den Heuvel
 
   PLYwoot is free software: you can redistribute it and/or modify
   it under the terms of the GNU 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/>.
*/
 
#ifndef PLYWOOT_ENDIAN_HPP
#define PLYWOOT_ENDIAN_HPP
 
 
#include <type_traits>
#include <utility>
 
namespace plywoot::detail {
 
struct LittleEndian
{
};
 
struct BigEndian
{
};
 
#if defined(_MSC_VER) && !defined(__clang__)
using HostEndian = LittleEndian;
#else
using HostEndian = std::conditional_t<__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__, LittleEndian, BigEndian>;
#endif
 
template<typename T>
T byte_swap(T t)
{
  unsigned char *bytes = reinterpret_cast<unsigned char *>(&t);
 
  if constexpr (sizeof(T) == 2) { std::swap(bytes[0], bytes[1]); }
  else if constexpr (sizeof(T) == 4)
  {
    std::swap(bytes[0], bytes[3]);
    std::swap(bytes[1], bytes[2]);
  }
  else if constexpr (sizeof(T) == 8)
  {
    std::swap(bytes[0], bytes[7]);
    std::swap(bytes[1], bytes[6]);
    std::swap(bytes[2], bytes[5]);
    std::swap(bytes[3], bytes[4]);
  }
 
  return t;
}
 
}
 
#endif