byte_order.h

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/*
 * Software License Agreement (BSD License)
 *
 *  Point Cloud Library (PCL) - www.pointclouds.org
 *  Copyright (c) 2007-2012, Ares Lagae
 *  Copyright (c) 2012, Willow Garage, Inc.
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 *  modification, are permitted provided that the following conditions
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 *     disclaimer in the documentation and/or other materials provided
 *     with the distribution.
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 *     from this software without specific prior written permission.
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#pragma once
 
#include <boost/predef/other/endian.h>
 
#include <cstddef>
#include <utility> // for swap
 
namespace pcl
{
  namespace io
  {
    namespace ply
    {
      /** \file byte_order.h
        * defines byte shift operations and endianness.
        * \author Ares Lagae as part of libply, Nizar Sallem
        * \ingroup io
        */
 
      enum byte_order
      {
        little_endian_byte_order,
        big_endian_byte_order,
#if BOOST_ENDIAN_BIG_BYTE
        host_byte_order = big_endian_byte_order,
#elif BOOST_ENDIAN_LITTLE_BYTE
        host_byte_order = little_endian_byte_order,
#else
#error "unable to determine system endianness"
#endif
        network_byte_order = big_endian_byte_order
      };
 
      template <std::size_t N>
      void swap_byte_order (char* bytes);
 
      template <>
      inline void swap_byte_order<1> (char*) {}
 
      template <>
      inline void swap_byte_order<2> (char* bytes)
      {
        std::swap (bytes[0], bytes[1]);
      }
 
      template <>
        inline void swap_byte_order<4> (char* bytes)
      {
        std::swap (bytes[0], bytes[3]);
        std::swap (bytes[1], bytes[2]);
      }
      
      template <>
        inline void swap_byte_order<8> (char* bytes)
      {
        std::swap (bytes[0], bytes[7]);
        std::swap (bytes[1], bytes[6]);
        std::swap (bytes[2], bytes[5]);
        std::swap (bytes[3], bytes[4]);
      }
      
      template <typename T>
      void swap_byte_order (T& value)
      {
        swap_byte_order<sizeof (T)> (reinterpret_cast<char*> (&value));
      }
 
    } // namespace ply
  } // namespace io
} // namespace pcl