#ifndef __BEELIB_ENDIANNESS_H__
#define __BEELIB_ENDIANNESS_H__

/*

Copyright (c) 2007 Andrew Molloy

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 "BeeLib.h"
#include <boost/detail/endian.hpp>
#include <boost/static_assert.hpp>
#include <boost/type_traits/is_arithmetic.hpp>

namespace BeeLib 
{
   enum Endianness
   {
   BigEndian,
   LittleEndian,
#if defined(BOOST_BIG_ENDIAN)
   HostEndianness = BigEndian
#elif defined(BOOST_LITTLE_ENDIAN)
   HostEndianness = LittleEndian
#else
#error BeeLib only supports big and little endian systems.  Sorry, PDP!
#endif
   };

   template<class T> T swapBytes2(T in);
   template<class T> T swapBytes4(T in);
   template<class T> T swapBytes8(T in);

   template<bool, size_t>
   class swapBytes_impl
   {
      template <class T> static T swapBytes_(T in) { return in; }
      template<Endianness, Endianness, class T> friend T swapBytes(T);
   };
    
   // specialize for the cases where a swap is needed
   template<> 
   class swapBytes_impl<false, 2>
   {
      template <class T>
      static T swapBytes_(T in)
      {
         return swapBytes2(in);
      }
      template<Endianness, Endianness, class T> friend T swapBytes(T);
   };

   template<> 
   class swapBytes_impl<false, 4>
   {
      template <class T>
      static T swapBytes_(T in)
      {
         return swapBytes4(in);
      }
      template<Endianness, Endianness, class T> friend T swapBytes(T);
   };
   
   template<> 
   class swapBytes_impl<false, 8>
   {
      template <class T>
      static T swapBytes_(T in)
      {
         return swapBytes8(in);
      }
      template<Endianness, Endianness, class T> friend T swapBytes(T);
   };
    
   // this is what you call.  
   template<Endianness in_endian, Endianness out_endian, class T>
   T swapBytes(T in)
   {
      // make sure we can actually handle this sized data
      BOOST_STATIC_ASSERT(sizeof(T) == 2 || sizeof(T) == 4 || sizeof(T) == 8);
      // Don't try to swap anything except built-in arithmetic types (integers & floats)
      // If you, for some reason, you think your data should be swapped as-is, then you'll
      // need to cast it to the appropriately sized type yourself. You should also reconsider
      // your design, because it's very possibly wrong. Keep in mind, also, that swapping a
      // pointer makes very little sense.
      BOOST_STATIC_ASSERT(boost::is_arithmetic<T>::value);
      
      return swapBytes_impl<in_endian == out_endian, sizeof(T)>::swapBytes_(in);
   }
      
   // some convenience functions
   template<class T>
   T hostToLittle(T in)
   {
      return swapBytes<HostEndianness, LittleEndian>(in);
   }

   template<class T>
   T hostToBig(T in)
   {
      return swapBytes<HostEndianness, BigEndian>(in);
   }

   template<class T>
   T littleToHost(T in)
   {
      return swapBytes<LittleEndian, HostEndianness>(in);
   }

   template<class T>
   T bigToHost(T in)
   {
      return swapBytes<BigEndian, HostEndianness>(in);
   }
}

#if defined(BEELIB_NO_INLINE_ASM)
#include "Endianness.tcc"
#else // defined(BEELIB_NO_INLINE_ASM)

#if defined(__i386__)
#include "Endianness_i686.tcc"
#else
#include "Endianness.tcc"
#endif

#endif // defined(BEELIB_NO_INLINE_ASM)

#endif