endian64.hpp

//    OpenVPN -- An application to securely tunnel IP networks
//               over a single port, with support for SSL/TLS-based
//               session authentication and key exchange,
//               packet encryption, packet authentication, and
//               packet compression.
//
//    Copyright (C) 2012-2021 OpenVPN Inc.
//
//    This program is free software: you can redistribute it and/or modify
//    it under the terms of the GNU Affero General Public License Version 3
//    as published by the Free Software Foundation.
//
//    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 Affero General Public License for more details.
//
//    You should have received a copy of the GNU Affero General Public License
//    along with this program in the COPYING file.
//    If not, see <http://www.gnu.org/licenses/>.

#pragma once

#include <cstdint>

#include <openvpn/common/endian_platform.hpp>

namespace openvpn {
  namespace Endian {
#ifdef __MINGW32__
    inline std::uint64_t mingw_bswap64(const std::uint64_t val)
    {
      return (((val & (uint64_t)0x00000000000000ffULL) << 56) |
              ((val & (uint64_t)0x000000000000ff00ULL) << 40) |
              ((val & (uint64_t)0x0000000000ff0000ULL) << 24) |
              ((val & (uint64_t)0x00000000ff000000ULL) <<  8) |
              ((val & (uint64_t)0x000000ff00000000ULL) >>  8) |
              ((val & (uint64_t)0x0000ff0000000000ULL) >> 24) |
              ((val & (uint64_t)0x00ff000000000000ULL) >> 40) |
              ((val & (uint64_t)0xff00000000000000ULL) >> 56));
    }
#endif
    inline std::uint64_t rev64(const std::uint64_t value)
    {
#ifdef OPENVPN_LITTLE_ENDIAN
#if defined(_MSC_VER)
      return _byteswap_uint64(value);
#elif defined(__MINGW32__)
      return mingw_bswap64(value);
#elif defined(__clang__) || !defined(__GLIBC__)
      return __builtin_bswap64(value);
#else
      return __bswap_constant_64(value);
#endif /* _MSC_VER */
#else
      return value;
#endif /* OPENVPN_LITTLE_ENDIAN */
    }
  }
}